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Sunday, 26 December 2010

Clinical evaluation of dental restorative materials - Part III: FDI criteria

In 2007, recommendations for conducting clinical trials approved by the FDI were published in several peer-reviewed journals. These recommendations not only addressed designing protocols for clinical trials but also challenged the Ryge criteria with an in-depth discussion of  clinical evaluation criteria and suggested a new approach in clinical evaluation of dental restorative materials and operative techniques.

In August 2010, an update of the "FDI clinical criteria for the evaluation of direct and indirect restorations" was published  by Hickel et al. in the Journal of Adhesive Dentistry and Clinical Oral Investigations. A lot of clinical examples were presented in the paper to illustrate various ratings.

The new FDI criteria set a different background for the evaluation of dental restorations by introducing 3 groups of criteria: esthetic, functional and biological. Each of these groups has subgroups with 16 evaluation criteria in total. These are:

Esthetic criteria
  1. Surface luster
  2. Staining: (a) surface and (b) margin
  3. Color match and translucency
  4. Esthetic anatomical form
Functional criteria
  1. Fracture of material and retention
  2. Marginal adaptation
  3. Occlusal contour and wear 
  4. Approximal anatomical form: (a) contact point and (b) contour
  5. Radiographic examination, where applicable
  6. Patient's view
Biological criteria
  1. Postoperative sensitivity and tooth vitality
  2. Recurrence of caries, erosion, abfraction
  3. Tooth integrity
  4. Periodontal response
  5. Adjacent mucosa
  6. Oral and general health
For all three groups, the following gradings are used for evaluation:
  1. Clinically excellent/very good
  2. Clinically good
  3. Clinically sufficient/satisfactory
  4. Clinically unsatisfactory
  5. Clinically poor
When judging a dental restoration using the FDI criteria, the score for each group is dictated by the most severe grading among the criteria for that particular group. Similarly, the overall score is determined by the worst grading among the groups. For example, if the functional criteria are unacceptable, the overall score is unacceptable. Detailed description of each grading is given in the previously mentioned paper: "FDI World Dental Federation - Clinical Criteria for the evaluation of direct and indirect restorations".

It is not mandatory to apply all of the FDI criteria in each study. In each particular study, the examiners should determine which criteria match their intended purposes best.

Gradings for the FDI criteria are substantially more detailed and sensitive than the Cvar and Ryge criteria and their modifications suggested by other authors. These detailed gradings challenge the training and calibration procedure of the examiners. To allow an easier and more efficient training, reduced variability in judgment and greater coherence in multi-centric studies, an online calibration system was established at www.e-calib.info. It is emphasized by the authors of the FDI criteria that the e-calibration system does not replace the clinical setting but shortens clinical training significantly.

Beside their use in clinical trials, the FDI criteria are recommended for quality assessment of restorations by general dental practitioners in their everyday practice and as guidelines whether or not a restoration needs refurbishment, repair or replacement. Refurbishment is a minimal intervention such as polishing or contouring when no additional material is placed. Repair is a minimal intervention which requires additional material to be placed with or without a minimal preparation in the restoration or dental tissues.

Clinical investigators are strongly advised to use the new FDI criteria when designing and conducting clinical trials. However, the criteria are "not indefinitely fixed and defined" so investigators are asked for feedback and encouraged to contribute to the e-calib database with high quality images of clinical cases.

References

Hickel R, Peschke A, Tyas M, Mjör I, Bayne S, Peters M, Hiller KA, Randall R, Vanherle G, Heintze SD. FDI World Dental Federation - clinical criteria for the evaluation of direct and indirect restorations. Update and clinical examples. J Adhes Dent. 2010 Aug;12(4):259-72. doi: 10.3290/j.jad.a19262.

Hickel R, Roulet JF, Bayne S, Heintze SD, Mjör IA, Peters M, Rousson V, Randall R, Schmalz G, Tyas M, Vanherle G. Recommendations for conducting controlled clinical studies of dental restorative materials. Science Committee Project 2/98--FDI World Dental Federation study design (Part I) and criteria for evaluation (Part II) of direct and indirect restorations including onlays and partial crowns. J Adhes Dent. 2007;9 Suppl 1:121-47.

Sunday, 19 December 2010

Clinical evaluation of dental restorative materials - Part II: Modified Ryge criteria

Cvar and Ryge criteria[1] for clinical evaluation of dental restorative materials were first published in 1971 and re-evaluated in 1980 by Ryge.[2] Another post explains the original Cvar and Ryge criteria in greater detail. Also, read about the new FDI criteria in a separate post.

Modified criteria, often called modified Ryge criteria are mostly used in contemporary clinical evaluations of dental restorative materials. Modifications usually depend on the aim of the study i.e. the type(s) of restorations that are being compared. Here are some studies reporting on clinical performance of restorative materials based on modified Ryge criteria.

Gallo et al.[3] conducted a three-year clinical evaluation of two flowable composites, Tetric Flow (Ivoclar Vivadent) and Esthet-X Flow (Dentsply/Caulk) which were used to restore Class I caries lesions. The authors used the original Cvar and Ryge criteria with two additional criteria: (1) retention and (2) polishability. Table 1 presents the codes and descriptions for each criterion. It should be noted that polishability is rated using more than the original 4 codes, introducing subtle differences in rating. This may, however, affect the variability of diagnostic judgement and intra- or inter-examiner reliability as it becomes more difficult to differentiate between e.g. Bravo B-a and B-b or C and D. Also, the term “unacceptable polish” comes as a rather unexpected vague description in contrast to detailed codes A-D and it is unclear what unacceptable means. For some dentists, “Rough and dull or satin, not reflective” may be completely “Unacceptable polish”. An obvious principle adopted by Cvar and Ryge in their original criteria should also be applied when modifying these criteria by introducing new ones – keep it simple.

Table 1. Codes and descriptions of two additional criteria, as used in Gallo et al.
(Click on the table)








Poon et al.[4] conducted a 3.5-year clinical evaluation of a packable (SureFil, Dentsply DeTrey) and a conventional (SpectrumTPH, Dentsply DeTrey) composite used with a self-etch adhesive system. Not only did the authors add more criteria, they also modified the descriptions of the original Cvar and Ryge criteria. Additional criteria were: (1) Retention, (2) Surface texture, (3) Surface staining, (4) Postoperative sensitivity and (5) Gingival bleeding in Class II restorations. All criteria in this study, with the exception of Postoperative sensitivity and Gingival bleeding, were rated as Alfa (A) or Bravo (B), where A was defined as “restorations meet all clinical standards with a range of excellence” and B was “though not ideal, restorations have a range of acceptability”. The rating for Postoperative sensitivity and Gingival Bleeding were “absent” or “present”.

Swift et al.[5] compared the 3-year clinical performance of two-step total-etch adhesives (OptiBond Solo, SDS Kerr and Prime & Bond 2.1, Dentsply Caulk). Their additional criteria were: (1) Retention, codes as in Table 1, (2) Postoperative sensitivity and (3) Other failure. The latter two were rated as “none” or “present”.

Moncada et al.[6] conducted a 3-year clinical trial to compare various treatment options for Class I and II restorations (sealed margins, repair, refurbishment, replacement or no treatment). Unlike previous cited papers, Moncada et al. did not use all of the original Cvar and Ryge criteria but selected only the following: (1) Marginal adaptation, (2) Anatomic form and (3) Caries. Also, they added two new criteria: (1) Surface roughness and (2) Luster, described in Table 2.

Table 2. Codes and descriptions of two additional criteria, as used in Moncada et al.
(Click on the table)















Kihn and Barnes[7] investigated clinical longevity of porcelain veneers after 4 years. They substituted Anatomic form from the original Cvar and Ryge criteria with Postoperative sensitivity which was rates “absent” or “present”.

Hamilton et al.[8] used modified Ryge criteria to evaluate pit and fissure restorations after 1 year of clinical service. Instead of the original Caries criterion, the authors added Surface smoothness which was rated as follows:

A - As smooth as natural adjacent tooth structure
B - Not as smooth as natural tooth structure but not pitted
C - Not as smooth as natural tooth structure and pitted

Hamilton et al.[8] also modified Margin discoloration and Margin adaptation to include subrating as described in Table 3. Quantification of discoloration along the margin was used and restorations rated as B1 for less than 50% of exposed margin or B2 for greater than 50% of exposed margin. A subtle one-way catch with an explorer during the assessment of margin adaptation was tolerated and rated as A2 instead of B. Also, code D for margin adaptation (Restoration mobile, fractured or missing in part of the tooth) was not taken into account, most likely because none was found.

Table 3. Modifications of the original Cvar and Ryge criteria by Hamilton et al.
(Click on the table)










Conclusions

Based on this short literature review, it is apparent that in contemporary clinical evaluation of restorative materials and treatment modalities, the original Cvar and Ryge criteria are modified in some way based on study objectives. These modifications include:

(1) Additional criteria are introduced: Retention, Polishability, Postoperative sensitivity, Surface roughness, Surface staining, Luster, Gingival bleeding; 

(2) Not all of the original Cvar and Ryge criteria are used; 

(3) Subrating are introduced to increase the precision of clinical judgment or the quality of the original criteria is reduced either through poorer description of rating or by excluding rating.

Despite the limitations, Cvar and Ryge rating scales, with or without modifications, remain the most frequently used method of clinical evaluation of dental restorative materials and operative techniques.

References
1. Cvar and Ryge criteria for the clinical evaluation of dental restorative materials. First published in U.S. Department of Health, Education, and Welfare, U.S. Public Health Service 790244, San Francisco Printing Office 1971:1–42. Reprinted in Clinical Oral Investigations 2005;9:215–232.
2. Ryge G. Clinical criteria. Int Dent J 1980;30:347-58
3. Gallo JR, Burgess JO, Ripps AH, Walker RS, Maltezos MB, Mercante DE, Davidson JM. Three-year clinical evaluation of two flowable composites. Quintessence Int. 2010 Jun;41(6):497-503.
4. Poon EC, Smales RJ, Yip KH. Clinical evaluation of packable and conventional hybrid posterior resin-based composites: results at 3.5 years. J Am Dent Assoc. 2005 Nov;136(11):1533-40.
5. Swift EJ Jr, Perdigão J, Wilder AD Jr, Heymann HO, Sturdevant JR, Bayne SC. Clinical evaluation of two one-bottle dentin adhesives at three years. J Am Dent Assoc. 2001 Aug;132(8):1117-23.
6. Moncada G, Martin J, Fernández E, Hempel MC, Mjör IA, Gordan VV. Sealing, refurbishment and repair of Class I and Class II defective restorations: a three-year clinical trial. J Am Dent Assoc. 2009 Apr;140(4):425-32.
7. Kihn PW, Barnes DM. The clinical longevity of porcelain veneers: a 48-month clinical evaluation. J Am Dent Assoc. 1998 Jun;129(6):747-52.
8. Hamilton JC, Dennison JB, Stoffers KW, Welch KB. A clinical evaluation of air-abrasion treatment of questionable carious lesions. A 12-month report. J Am Dent Assoc. 2001 Jun;132(6):762-9.

Monday, 13 December 2010

Clinical evaluation of dental restorative materials - Part I: Cvar and Ryge criteria

Nearly 40 years ago John F. Cvar and Gunnar Ryge wrote that, although mechanical properties of the available dental restorative materials were well known, clinical scientific data were scarce. The lack of evidence-based studies was the result of the lack of well-defined measures to evaluate the clinical performance of dental materials. As a fast and relatively reliable solution, Cvar and Ryge developed the rating scales which assess five characteristics of dental restorative materials indicative of their aesthetics and functionality.(1) With some modifications, these criteria are still used in clinical evaluation of dental materials and operative techniques. Read about modified criteria and the new FDI criteria in separate posts.

The original Cvar and Ryge criteria or characteristics used for material clinical evaluation are color match, cavo-surface marginal discoloration, anatomic form, marginal adaptation and caries. Codes Alfa, Bravo, Charlie and Delta are used to rate the restorations according to the assigned descriptive values for each characteristic (Table 1). The rating is conducted in a clinical setting, usually by two examiners (dentists) and a recorder (e.g. dental assistant), by visual inspection of the restoration with the use of a mirror if necessary. In addition, an explorer is used to rate marginal adaptation and the presence of caries.

In 1980, Ryge published another paper on clinical criteria in which he systematically set out an approach in clinical assessment of restorative materials using the original Cvar and Ryge criteria.(2) In addition to the previously developed rating scales, Ryge introduced a classification of restorations. The four categories are:
  1. Restorations within a range of excellence,
  2. Restorations which are acceptable although showing minor deviations from the ideal,
  3. Restoration which should be replaced for preventive reasons to avoid the likelihood of future damage and
  4. Restorations which require immediate replacement.

Table 1. Original Cvar and Ryge criteria used to evaluate non-metallic restorations. (Click on the table)























References

1. Cvar and Ryge criteria for the clinical evaluation of dental restorative materials. First published in U.S. Department of Health, Education, and Welfare, U.S. Public Health Service 790244, San Francisco Printing Office 1971:1–42. Reprinted in Clinical Oral Investigations 2005;9:215–232.

2. Ryge G. Clinical criteria. Int Dent J 1980;30:347-58

Tuesday, 30 November 2010

ADA: WHO releases report on dental materials, amalgam

American Dental Association - WHO releases report on dental materials, amalgam

Dental amalgam is rapidly fading out from dental practice due to the increased use of aesthetic restorative materials, particularly resin-based composites, for restorations in posterior teeth. However, the debate about the safety of dental amalgam seems to be a never-ending subject. Amalgam opponents go as far as to request this material to be banned due to the toxicity and health issues associated with mercury (oral lesions, autoimmune disorders, chronic illnesses etc.)

In a recent report, the World Health Organization (WHO) states that dental amalgam remains a dental restorative material of choice reaffirming the safety of this material. Nevertheless, the WHO report emphasizes that alternative materials and preventive measures should be further improved and implemented.

In 2009, ADA and FDA agreed that dental amalgam should not be restricted from dental practice since the scientific literature supports amalgam as "a valuable, viable and safe choice for dental patients". Read more about this in another post.

It seems that amalgam will eventually cease to be used in dentistry not because of its safety issues but because of considerable improvements of aesthetic materials.

Monday, 15 November 2010

Mineral Trioxide Aggregate (MTA): Free full text articles II

To see previously published list of free full text articles on MTA (part I), please click here.

Endodontics - Case reports

Unal GC, Maden M, Isidan T. Repair of Furcal Iatrogenic Perforation with Mineral Trioxide Aggregate: Two Years Follow-up of Two Cases. Eur J Dent. 2010 Oct;4(4):475-81.  

Yildirim T, Gencoglu N. Use of mineral trioxide aggregate in the treatment of large periapical lesions: reports of three cases. Eur J Dent. 2010 Oct;4(4):468-74.

Abarajithan M, Velmurugan N, Kandaswamy D. Management of recently traumatized maxillary central incisors by partial pulpotomy using MTA: Case reports with two-year follow-up. J Conserv Dent. 2010 Apr;13(2):110-3.

Chhabra N, Singbal KP, Kamat S. Successful apexification with resolution of the periapical lesion using mineral trioxide aggregate and demineralized freeze-dried bone allograft. J Conserv Dent. 2010 Apr;13(2):106-9.

Adiga S, Ataide I, Fernandes M, Adiga S. Nonsurgical approach for strip perforation repair using mineral trioxide aggregate. J Conserv Dent. 2010 Apr;13(2):97-101.

Ozbas H, Subay RK, Ordulu M. Surgical retreatment of an invaginated maxillary central incisor following overfilled endodontic treatment: a case report. Eur J Dent. 2010 Jul;4(3):324-8.

Araújo RA, Silveira CF, Cunha RS, De Martin AS, Fontana CE, Bueno CE. Single-session use of mineral trioxide aggregate as an apical barrier in a case of external root resorption. J Oral Sci. 2010;52(2):325-8.

Khatavkar RA, Hegde VS. Use of a matrix for apexification procedure with mineral trioxide aggregate. J Conserv Dent. 2010 Jan;13(1):54-7.

Mirikar P, Shenoy A, Mallikarjun GK. Nonsurgical management of endodontic mishaps in a case of radix entomolaris. J Conserv Dent. 2009 Oct;12(4):169-74.

Endodontics - scientific articles
Orosco FA, Bramante CM, Garcia RB, Bernardineli N, de Moraes IG. Sealing ability, marginal adaptation and their correlation using three root-end filling materials as apical plugs. J Appl Oral Sci. 2010 Mar-Apr;18(2):127-34.

Biocompatibility
Lessa FC, Aranha AM, Hebling J, Costa CA. Cytotoxic effects of White-MTA and MTA-Bio cements on odontoblast-like cells (MDPC-23). Braz Dent J. 2010 Jan;21(1):24-31.

Cintra LT, Bernabé PF, de Moraes IG, Gomes-Filho JE, Okamoto T, Consolaro A, Pinheiro TN. Evaluation of subcutaneous and alveolar implantation surgical sites in the study of the biological properties of root-end filling endodontic materials. J Appl Oral Sci. 2010 Feb;18(1):75-82.

Chemical analysis

Han L, Okiji T, Okawa S. Morphological and chemical analysis of different precipitates on mineral trioxide aggregate immersed in different fluids. Dent Mater J. 2010 Oct 14;29(5):512-7.

Thursday, 11 November 2010

Silorane technology in restorative dentistry - material properties and clinical application

I recently published a review article in the Serbian professional journal "Stomatolog" ["Dentist"] on Filtek Silorane material properties and clinical application steps. The article is in Serbian but I would be happy to translate it to English for interested colleagues. Contact me at vesna.miletic@gmail.com

Abstract

Polymerization shrinkage remains one of the main weaknesses of composite materials. Silorane technology significantly reduces material shrinkage compared to methacrylate composites. This review article compares chemical composition and polymerization process of methacrylate- and silorane-based composites. Systematically are reviewed studies on mechanical, aesthetic, antibacterial and chemical properties of Filtek Silorane, as well as its interaction with tooth tissues. Lower polymerization shrinkage and microbial adherence and comparable mechanical properties have been reported for Filtek Silorane compared to methacrylate-based composites. In the only clinical study that has been published so far, marginal adaptation of Filtek Silorane was found to be inferior than the nanocomposite Ceram.X  However, low inter-examiner reliability questions the results of this clinical study and scientific literature lacks more information on clinical performance of Filtek Silorane. 

Wednesday, 13 October 2010

Monomer elution from a dental composite

Recently, I started a series of studies on monomer elution from composites with colleagues from University of Belgrade School of Dentistry and Faculty of Technology and Metallurgy. One of these experiments was presented a month ago at an international material science and engineering conference YUCOMAT.

The nano-hybrid composite Filtek Z250 (3M ESPE) was used to study elution kinetics of monomers UDMA and HEMA over 28 days post-immersion in either distilled water or 75% ethanol. Kinetic models were proposed and it was shown that monomer elution followed the first order law for both UDMA and HEMA irrespective of the medium. However, there were some differences in that UDMA eluted more rapidly during the first 24 h and then much more slowly over the 28-day period. This indicates that during the first 24 h elution from the sample surface occurred whereas the slow phase corresponds to monomer elution from inside the polymer. On the other hand, HEMA did not start to elute immediately, but only after 24 h and the eluted concentrations increased over the 28 days. Though HEMA is not a genuine ingredient of the studied composite, its slow elution and small eluted amounts seem to support a previous statement by other authors that HEMA could elute as a product of degradation of UDMA. (We are currently investigating this hypothesis.)

Monday, 4 October 2010

Dental Materials Blog: Year 1

It has been a year since I started writing on this blog. During this first year, nearly 6700 visits and 12000 pageviews have been made by more than 5300 unique visitors. The average number of visits per day has been increasing constantly and currently is 17.70. What I am particularly proud is that one fifth of all visitors have returned and visited the blog more than once. Another important figure is that visitors come from more than 120 countries in the world (Figure 1.). The importance of this information is not so much related to the blog itself, but shows that in almost every corner of the Earth people search for dental information and want to expand their knowledge.
Figure 1. Map overlay

The most frequently visited posts are related to MTA in endodontics and the list of free full texts, self-adhering composite Vertise Flow and nano-filled, resin-modified glass ionomer Ketac N100. Likewise, the most frequently used keywords are "dental materials", ""MTA dental material", ""MTA dental", "mineral trioxide aggregate",  "Vertise Flow"...

Comments were disabled for most of the year, because I haven't noticed there was a problem, but a visitor drew my attention to it. Comments are now fixed and those received so far are all very positive.

I would like to encourage fellow researchers and clinicians to contribute to the Dental Materials Blog with their own posts, it is free and the choice of topics is entirely up to the authors.

Sunday, 12 September 2010

Journal of Esthetic and Restorative Dentistry gets its first impact factor

A Miletic et al. study among the top 5 cited papers

In the latest list of SCI Journal Impact Factors 2009 published by Thomson Reuters, Journal of Esthetic and Restorative Dentistry is listed with the impact factor of 0.797. The Journal thanks all authors, reviewers and readers and allows free access to the top cited articles. Easy online submissions through ScholarOne Manuscripts are encouraged as this speeds up the review process. Hopefully, the Journal will maintain a growing influence in the scientific literature and increase its impact factor in the future.


It was a pleasure to see that one of the papers I did with my colleagues at the University of Belgrade School of Dentistry was among the top 5 cited articles in the Journal of Esthetic and Restorative Dentistry.

Miletic V, Ivanovic V, Dzeletovic B, Lezaja M.
Temperature Changes in Silorane-, Ormocer-, and Dimethacrylate-Based Composites and Pulp Chamber Roof during Light-Curing.

I look forward to submitting the results of my current studies to the Journal of Esthetic and Restorative Dentistry.

Tuesday, 7 September 2010

Recent books on dental materials II

The previous "Recent books" list on this blog is updated with, according to some scholars, the best book in this field.

Now in its ninth edition, Materials Science for Dentistry by Professor Brian W. Darvell (2009, 688 pages) continues its reputation as the most authoritative available reference for students of dentistry. It is also a valuable resource for academics and practitioners in the field. 


For more information about the book and the author, please visit publisher's website

Wednesday, 1 September 2010

News from jobs.ac.uk

University of Birmingham - School of Dentistry

Fixed Term for 12 months

The main purpose of the post will be to undertake a series of activities that have been identified which will contribute to the creation of a mechanistic understanding of how polymer adhesives interact with ceramic surface defects and confer reinforcement. Innovative steps will be made to optimise ceramic reinforcement ultimately leading to novel solutions to prevent the fracture of dental ceramic restorations in service.

The candidate should have a degree in Materials Science, Engineering or Chemical Engineering and hold a PhD or be near completion of a PhD.

Salary from £27,319 to £35,646 a year, with potential progression to £37,839 a year. Maximum starting salary £27,319 a year

Closing date: 10th September 2010

Friday, 23 July 2010

Tooth bleaching techniques - clinical steps

Take a look at the clinical steps of tooth bleaching presented by my dear colleague and friend, Tatjana Savic Stankovic BDS, MSc from University of Belgrade School of Dentistry. For more information, contact Dr Savic Stankovic by email tanjeze@gmail.com


If you can't see this presentation, you should download Adobe Flash Player. It's free. Click here.

Monday, 19 July 2010

88th IADR General Session (Barcelona, 2010)

Effect of Preparation and Storage on Adhesive Monomer Conversion

V. MILETIC,  University of Belgrade, Belgrade, Serbia,  
A. SANTINI, The University of Edinburgh, Edinburgh, United Kingdom
Objectives: To study the effect of sample preparation and storage conditions on the degree of conversion (DC) of two adhesive systems using micro-Raman spectroscopy.  
Methods: Sixty samples each of an etch-and-rinse (Excite) and a self-etch (Clearfil 3S) adhesive were prepared on glass slides and allocated to groups G1-G6 (n=10). Thirty samples of each adhesive were prepared on dentine discs according to manufacturer's instructions and allocated to groups D1-D6 (n=5). In groups G1 and D1, each sample was covered with a Mylar strip and cured for 10 s with a bluephase LED unit. In groups G2 and D2, samples were cured without the Mylar strip. Micro-Raman spectra were taken 5 min post-curing. Groups G3-G6 and D3-D6 were covered with Mylar strips, cured according to the same protocol and stored for 24 h: G3 and D3 at 22±2ºC and 45±3% humidity; G4 and D4 at 37±1ºC and 90±2% humidity; G5 and D5 in distilled water at 37±1ºC; G6 and D6 in buffered incubation medium at 37±1ºC. Micro-Raman spectra were taken 5 min post-curing and after storage. Data were analyzed using t-tests and repeated measures ANOVA and the level of significance was α=0.05.
Results: Higher DC values were found on dentine than glass for both adhesives (p<0.05). Higher DC values were found for both adhesives when cured on dentine with than without Mylar strips (p<0.05). Higher DC values were found for Excite cured on glass with than without Mylar strips (p<0.05), but there was no difference for Clearfil 3S (p>0.05). Both adhesives cured on dentine gave higher DC after 24 h storage irrespective of the medium (p<0.05). Excite G3 group and Clearfil 3S G3 and G4 groups showed higher DC values after storage (p<0.05).
Conclusions: Sample preparation methods and storage conditions significantly affected the DC of Excite and Clearfil 3S.


If you can't see this presentation, you should download Adobe Flash Player. It's free. Click here.

Wednesday, 7 July 2010

Current status of visible light activation units and the curing of light-activated resin-based composite materials - review by professor Ario Santini in Dental Update

Abstract
Light activation units are standard items of equipment in dental practice. It is essential to understand the many factors which affect the polymerization of light-activated resin composite materials and the choice of a light curing unit. In this respect, the development of high-intensity halogen and light-emitting diode (LED) light curing units (LCUs), many with multiple curing modes, has revolutionized light curing techniques. This article reviews visible light activation unit design and development. Factors influencing the effective use of LCUs and polymerization of resin-based composite materials are discussed, as are the steps which should be taken to maintain the efficiency of units in clinical use.
CLINICAL RELEVANCE: Many LCUs produce lower output intensities than stated by the manufacturer. Newer high power LEDs may present as much of a heat problem as high power quartz tungsten halogen lamps (QTHs). The manufacturer's data should be followed to ensure that the emission spectra of the unit are compatible with the photo-initiator in the resin-based composite material.

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Professor Ario Santini is the Director for Biomaterials Research at the Edinburgh Postgraduate Dental Institute, Chair Research at Faculty of General Dental Practice (UK), Professor at Faculty of Medicine and Surgery, University of Sassari (Italy), Visiting Professor at the University of Belgrade (Serbia) and Fellow of the Academy of Dental Materials. Professor Santini's research interests are dental material sciences, dental resin-based composites and adhesives, Raman spectroscopy, high performance liquid chromatography, pulp biology and research methodology. He has published numerous articles in international, peer-reviewed journals indexed in Thomson's Science Citation Index. Browse for more articles by professor Santini at http://www.santinimiletic.com/

Dental Update is the leading dental journal of continuing professional development (CPD) in the United Kingdom. By reading the appropriate peer reviewed articles and then answering the questions in each issue of the journal, one can earn up to 40 hours of verifiable CPD per year.

Tuesday, 25 May 2010

Free live dental webcast/webinar @ Pentron

A Science-based Protocol for Direct and Indirect Restorations that will End Post-Operative Sensitivity In Your Practice for Good!
Presenter Dr. Jeffrey Blank, D.M.D.
Thursday 27 May 2010 at 7 pm ET (midnight GMT 28 May 2010)
This webinar is CE accredited (1 CE point)|

It is essential to create a free account at http://pentron.vivalearning.com/  to register a seat. There are about 126 seats left at this moment.

From Pentron and J. Blank:  "
Reliably bonding direct and indirect restorations to both enamel and dentin is the single most important scientific discipline in modern dentistry. Over the past 18 years, adhesion has increased in effectiveness and predictability, but in turn has become complex and confusing. This CE presentation will address proper product selection, proper use of products and the variables that control the post-operative outcome."

Wednesday, 19 May 2010

Mineral Trioxide Aggregate (MTA) and direct pulp capping

Two papers have been published recently on the use of mineral trioxide aggregate (MTA) for direct pulp capping.

A large clinical trial was conducted between 2001 and 2006 at Ruprecht-Karls-University of Heidelberg, Germany (1). Direct pulp capping with either MTA or Calcium hydroxide was done in 167 teeth of 149 patients. Treatment outcome was evaluated clinically and radiographically by calibrated examiners 12-80 months post-treatment. The authors reported a high recall rate of more than 70% and based the statistical analysis on 108 patients and 122 treated teeth. A significantly greater success rate was found for MTA (78% of teeth) than Calcium hydroxide (60% of teeth). It seems critical to restore such teeth permanently as soon as possible after pulp capping. This study showed that teeth permanently restored ≥2 days after capping had a significantly worse prognosis irrespective of the capping material. The authors concluded that "MTA appears to be more effective than calcium hydroxide for maintaining long-term pulp vitality after direct pulp capping".

Another study is an immunohistological study on Wistar rats (2). It compared the proliferation of pulp cells 1, 3, and 7 days after direct pulp capping with either MTA or Calcium hydroxide. After 3 days, the number of proliferating cells (fibroblasts, endothelial cells and Hoell's cells) was significantly greater when capping was performed irrespective of the material compared to the control group with no capping. After 7 days, however, there were no differences between MTA and Calcium hydroxide groups and the control group. The authors concluded that "Immunohistologic analysis demonstrated that MTA showed similar results when compared with Calcium hydroxide within the first week after direct pulp capping".

(1) Mente J, Geletneky B, Ohle M, Koch MJ, Friedrich Ding PG, Wolff D, Dreyhaupt J, Martin N, Staehle HJ and Pfefferle T. Mineral trioxide aggregate or calcium hydroxide direct pulp capping: an analysis of the clinical treatment outcome. J Endod 2010;36:806-13.

(2) Dammaschke T, Stratmann U, Wolff P, Sagheri D and Schafer E. Direct pulp capping with mineral trioxide aggregate: an immunohistologic comparison with calcium hydroxide in rodents. J Endod 2010;36:814-9.

Reprints of both studies should be available from the authors: (1) johannes.mente@med.uni-heidelberg.de
and (2) tillda@uni-muenster.de

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Friday, 14 May 2010

Research Methodology in Dentistry seminar

It will be my great honour to lecture again along side my supervisor, Dr Ario Santini, at a seminar on Research Methodology in Dentistry. The seminar will take place at Belgrade University School of Dentistry on Thursday, June 10 (9am-1pm). The seminar is accredited by the Serbian Health Council and each attendee gets 4 CE points.



Programme:

9-9.15 Opening remarks
9.15-9.45 Dr Vesna Miletic: Literature search (MEDLINE and KoBSON)
9.45-10.45 Dr Ario Santini: Designing a study protocol
10.45-11 Break
11-12 Dr Ario Santini: Writing a scientific article
12-12.30 Dr Vesna Miletic: Managing references with EndNote
12.30-1 pm Discussion and practical work

The seminar is free for professors and clinical lecturers of Belgrade School of Dentistry. Contact me at vesna.miletic@gmail.com  to reserve a seat.

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Thursday, 29 April 2010

News from Esstech, Inc.

Esstech, Inc. develops and manufactures advanced materials for many biomedical fields including dental materials. In their range of products are various monomers, initiators, silanated glass etc. for resin-based composites and adhesive systems. The latest research by or using Esstech's products includes studies on physical properties of new low shrink resin , optimizing the degee of conversion and certain physical properties of various BisGMA/BisEMA/TEGDMA formulations , optimizing silanated glass , developing a high molecular mass monomer to substitute HEMA etc.

For more information, check out their website and blog.

Esstech, Inc. will be present at the IADR/AADR General Session in Barcelona, Spain (14-17 July 2010) and I really look forward to meeting their representatives, hoping that we could establish scientific collaboration.

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Sunday, 21 March 2010

Filtek Silorane composite: temperature changes during light-curing

Some time ago, my colleagues and I published a paper on temperature changes during curing of Filtek Silorane, Admira (ormocer) and Herculite XRV (microhybrid, control) composites. It was interesting to notice substantially higher temperature rise in Filtek Silorane compared to the other two materials. However, there was no difference in the temperature rise inside the pulp chamber, probably due to the insulating effect of the remaining dentine.

The abstract of this paper may be found on MEDLINE and I will be happy to email the full text to anyone interested in this subject. Feel free to contact me at vesna.miletic@gmail.com

J Esthet Restor Dent 2009;21(2):122-31.
Temperature changes in silorane-, ormocer-, and dimethacrylate-based composites and pulp chamber roof during light-curing.
Miletic V, Ivanovic V, Dzeletovic B, Lezaja M.

STATEMENT OF THE PROBLEM: Light-curing of resin-based composites (RBCs) is associated with temperature increase in the pulp chamber, which may have a detrimental effect on the vital pulp.
PURPOSE: The purpose of the study was to evaluate temperature changes of silorane-, ormocer-, and dimethacrylate-based RBCs at the bottom surface of the RBC and in the pulp chamber roof dentin (PCRD) during curing.  
MATERIALS AND METHODS: In part A, temperatures were measured for Filtek LS (3M ESPE, St. Paul, MN, USA), Admira (Voco GmbH, Cuxhaven, Germany), and Herculite XRV (Kerr Corp., Orange, CA, USA) with a high-power light-emitting diode (LED) unit by placing thermocouples in contact with the bottom surface of the material in standardized acrylic molds. In part B, temperature changes in PCRD were measured in extracted molars during light-curing of adhesives and RBCs in 2-mm-deep cavities with a remaining dentin thickness (RDT) of 1 mm.
RESULTS: Filtek LS showed a different temperature curve compared with Admira and Herculite XRV. Significantly higher temperatures were recorded for Filtek LS (p < 0.001) than for Admira and Herculite XRV in acrylic molds. Temperature rises recorded in PCRD for adhesives and RBCs were between 4.1 and 6.4 degrees C. No significant differences in PCRD temperatures were found between the three groups during adhesive curing and RBC curing (p > 0.05).  
CONCLUSIONS: Filtek LS showed a different heat-generation pattern from and significantly higher temperatures than Admira and Herculite XRV when the materials were tested in acrylic molds. Similar temperatures were recorded in the PCRD during curing of adhesives and RBCs.
CLINICAL SIGNIFICANCE: Although a substantial temperature rise in the bulk material occurred during light-curing of the three resin-based composites, a remaining dentin thickness of 1 mm caused a significant reduction in pulp chamber roof dentin temperatures. Temperatures measured in the pulp chamber roof dentin corresponding to the zone occupied by the postmitotic odontoblast layer were not statistically different for the three types of resin-based composites.

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Wednesday, 17 March 2010

Free live dental webinar @ GC Learning

Glass Ionomers: A Therapeutic Alternative to Direct Composite Restorations
Presenter: Dr Daniel Ward, D.D.S.
Time: 23-March-2010. 7:00 pm ET (midnight, 12 am GMT, 24-March-2010)

This webinar is credited with 1 CE credit.
Prior to entering the class, you have to create an account for free.

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Sunday, 14 March 2010

News from jobs.ac.uk

Reader in Biomaterials
The University of Manchester - School of Materials

Salary: £46,510 - £60,685 p.a.
Application deadline: 23 - March - 2010
Click here for more information.

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Friday, 12 March 2010

Refractive Index of Methacrylate Monomers & Polymers

It is my pleasure to share this post originally published by Esstech, Inc. www.esstechinc.com
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TECHNICAL BULLETIN:  Refractive Index of Monomers and Their Respective Polymers

The refractive index (RI) of photopolymers is an essential property for many applications.  For optical and coating applications, the RI can be related to the resultant gloss or clarity upon cure.  Within the dental industry, the refractive index of the organic polymer matrix, must match that of the inorganic filler and substrate in order to avoid obvious “lines” where the product is applied.

Various factors affect refractive index values.  The presence of conjugated ring structures contributes to increasing RI.  In general, larger molecular weight monomers have a tendency to possess a higher RI in comparison to their lower molecular weight counterparts.  Similar to this trend, high molecular weight functional groups like methacrylates have higher RI than their acrylate counterparts. Higher atomic weight atoms also seem to be predisposed to having higher RI.

Recognizing the importance of refractive index to our customers, Esstech has assembled RI data for a portion of our existing monomer products as well as their corresponding homopolymers.


Maintaining its position as an industry innovator, Esstech has also created functional, high refractive index materials.  Contact us to learn more about these novel materials and how Esstech can make a material to match your application.

 (P) 800-245-3800 / (P) 610-521-3800 / techsupport@esstechinc.com / www.esstechinc.com

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Saturday, 27 February 2010

The effect of light source on monomer conversion of dental adhesives

The most recent paper by Santini Miletic research group will be published in Journal of Adhesive Dentistry, hopefully in the next issue. The abstract is available on PubMed/MEDLINE.

J Adhes Dent. 2009 Nov 27. doi: 10.3290/j.jad.a17855. [Epub ahead of print]

Micro-Raman Assessment of the Ratio of Carbon-Carbon Double Bonds of Two Adhesive Systems Cured with LED or Halogen Light-curing Units.

Miletic V, Santini A.

Purpose: The purpose of the study was to compare the ratio of carbon-carbon double bonds (RDB) of two adhesive systems cured by five different light-curing units (LCUs) using micro-Raman spectroscopy.
Materials and Methods: Ten samples of an etch-and-rinse (Excite), a two-step self-etching adhesive system (AdheSE) - ie, primer and bond mixed - and AdheSE Bond only were prepared and cured with one of the following LEDs: Elipar Freelight2; Bluephase; SmartLite; Coltolux, each for 10 s; or a conventional halogen Prismetics Lite for 10 s or 20 s. Micro-Raman spectra were obtained from uncured and cured samples of all three groups to calculate the RDB. Data were statistically analyzed using ANOVA.  
Results: The mean RDB values were 62% to 76% (Excite), 36% to 50% (AdheSE Primer+Bond) and 58% to 63% (AdheSE Bond). At 20 s, Prismetics Lite produced significantly higher RDB in Excite than the other LCUs and Prismetics Lite at 10 s (p < 0.05). Prismetics Lite at 20 s and Elipar produced comparable RDB values of AdheSE Bond and AdheSE Primer+Bond (p > 0.05). Excite showed significantly higher RDB values than AdheSE (p < 0.05) whilst AdheSE Bond showed significantly higher RDB than AdheSE Primer+Bond (p < 0.05).  
Conclusion: The etch-and-rinse adhesive cured with the halogen LCU for 20 s gave higher conversion than LED LCUs or halogen for 10 s curing time. The highest intensity LED [Elipar] produced higher or comparable conversion compared to the lower intensity LED LCUs for the same curing time. The etch-and-rinse adhesive showed higher RDB than the self-etching adhesive system. The presence of the primer in the self-etching adhesive compromised polymerisation.

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Thursday, 18 February 2010

News from jobs.ac.uk

PhD Studentship in Biophysical Chemistry
University of Bristol - Department of Oral & Dental Science 
Deadline: February 25, 2010
Salary: around £13,000  plus tuition fees paid.
NB: Applicants should be from the UK or EU. They are unable to support applications from outside the EU.

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Monday, 8 February 2010

Statistics in dental materials research: 2 things to plan ahead

A couple of statistical issues should be considered when designing a study in dental materials science.

(1) What statistical test(s) will be used to test the null hypothesis/hypotheses?

It is recommended to design the experiment in such a way that it is possible to test the data using one “global” test such as analysis of variance (ANOVA). The effect of one independent factor on one response variable is tested using one-way ANOVA in many papers on dental materials. Such study design includes e.g. the comparison of the degree of conversion (DC) of several materials cured under the same curing conditions (light, intensity, time, distance). The null hypothesis would be that there is no difference between the means for different materials. So, the independent factor is ‘material’ and the response variable is ‘DC’.

Two-way ANOVA is used to test the effect of two independent factors, e.g. material and light-curing unit (e.g. 3 materials are cured with either a halogen or an LED light-curing unit). Testing for interaction between the two factors shows whether or not the differences caused by one factor are consistent on different levels of the other factor. If so, the interaction is not significant (e.g. the DC may be higher in each material when cured with a halogen unit than an LED unit). Alternatively, if these differences are not consistent, then the interaction is significant (the DC may be higher in some materials when cured with a halogen and in others when cured with an LED unit). In this case, a series of one-way ANOVA must be used to examine this interaction more closely. This will, however, result in multiple testing which by default increases the chance of making the Type I Error (rejecting the null hypothesis when it is true) and some sort of correction is necessary to keep the overall significance level at the usual alpha=0.05. This correction most often means a decrease in the individual alpha value which also reduces the power of the statistical test.

Three-way ANOVA is sometimes used in dental materials science to study the effect of three independent factors on a particular response variable (e.g. the effect of material, light-curing unit and curing time on the DC of resin-based composites). Researchers are often tempted to test more and more factors in order to make their experiments robust. However, one has to keep in mind that the interpretation of three-way ANOVA is more difficult that that of two-way ANOVA and the post-test corrections may significantly reduce the power of the test. These are by no means the only tests used and are only an indication of the type of studies carried out in dental materials science.

(2) Power and sample size – power is the probability of not making Type II Error (failing to reject the null hypothesis when is false) i.e. power is the probability of correctly rejecting the null hypothesis when the difference between the groups truely exists. In sample size calculation prior to an experiment, the power of 80% is generally used as the cut-off point. So, when calculating the number of samples for each group, we need to know the following: number of levels (groups) that we will be comparing; significance level; power; estimated standard deviation (determined in a pilot study or taken from the literature) and the difference between the groups that we consider clinically relevant and don’t want to miss in our statistical testing. This last one may be tricky, because we often don’t know what difference between the groups is clinically relevant in a way that might affect the clinical performance of the tested materials. In this case, we may base our decision on the literature data or we can do a pilot study to find out the likely difference in the response variable between our groups which we would then use in the sample size calculations. Alternatively, if we already have a pre-determined number of samples in each group, we may be able to determine the power of our statistical test (i.e. how certain we are that our conclusion is correct).

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Thursday, 4 February 2010

Free live dental webcast/webinar @ 3M ESPE Espertise

Stress Free Predictable Restorations
Presenter: Dr. George Warga, D.D.S.

Wednesday, February 17th, 2010
Time: 8:00 ET (1 am GMT on Feb. 18)
CE Credits: 1

About 180 seats still available.

From 3M ESPE Espertise (http://www.espertiseinteractivelearning.com/):
"Dr. Warga will introduce the product, the unique technology behind the Lava™ Chairside Oral Scanner C.O.S. and how it has benefitted his practice. He will discuss the advantages for the “single crown” dentist and will then proceed to discuss the use of the Lava C.O.S. on multiple prep restorations. Dr. Warga will share clinical case photos, and how he integrates the Lava C.O.S. into his other processes to produce consistently accurate and sophisticated restorations."

You have to create an account on 3M ESPE Espertise Interactive Learning site in order to claim a seat.

If you're unable to join live due to the time difference in your part of the world, this webcast will be available as one of On-Demand Classes. Unfortunately, there will be no possibility to interact with the presenter and ask questions.

Also, there are two more free webcasts on caries risk assessment. Click here for more information.

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Wednesday, 3 February 2010

Poll: What kind of dental information are you searching on the internet?

With the rapid expansion of the internet, there are all sorts of information available.

What is it that you are looking for most of the time?

Please, take a moment to vote and select one or more answers.



Thank you for voting :-)
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Tuesday, 2 February 2010

News from jobs.ac.uk

Postdoctoral Research Assistant

Centre for Oral Growth & Development
Barts and The London - Institute of Dentistry

Salary: £30,229 to £35,532

Application deadline: 26-February-2010.

Click here for more information.

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Monday, 1 February 2010

Statistics in dental research: A book review

In a addition to the previous post on statistics in dental research, I'd like to mention that Medical Statistics at a Glance is the best book on the subject I've seen. It contains all the basic things a dental materials scientist needs to know, from study designs, types of data and descriptive statistics to hypothesis testing, correlation and regression, survival analysis and Bayesian methods. The book is written in an exceptionally succinct and reader-friendly way, understandable to researchers with very little previous knowledge on statistics.

Theory is only given in the amount which is necessary to understand each concept. A very good feature of the book is that it explains most commonly used statistical tests in dental research: t-tests, analysis of variance (ANOVA), the non-parametric Mann-Whitney and Kruskal-Wallis test, chi-squared and McNemar's test. The assumptions for these tests are given but situations with departures from these assumptions are mentioned in terms of their effect and possible solutions.

Also, statistics for some more complex study designs is also presented, such as generalized linear models, multiple linear regression or methods for clustered data.

Medical Statistics at a Glance also serves as a fantastic reminder with an informative glossary and a detailed index of terms. It is an excellent value for money. I bought a new copy on eBay for about £20 but I'm sure it can be found elsewhere on the internet.

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Wednesday, 27 January 2010

Statistics in dental research: A challenge for a dental materials scientist

Dental research relies heavily on statistics and in the majority of studies some sort of statistics is necessary. This goes beyond the descriptive statistics (the measures of central tendency and spread) and includes hypothesis testing using parametric or non-parametric tests. Sometimes other tests are used depending on the research question and the hypothesis. As far as I can remember, the only type of research where I haven't seen any statistics done in dental materials science is finite element analysis which involves computer simulation of stresses and strains on bone and/or tooth models. This approach does not require sampling and therefore no statistics is performed.

The validity of results and conclusions depends, among other things, on the appropriate statistical test(s). I'm pretty sure dentists and material scientists who conduct research but are not familiar with statistics feel this may be their main weekness. In all research methodology courses, it is strongly advised to consult a statistician prior to conducting a study because even in the planning stage of the study, statistics is unavoidable as it is necessary to perform sample size and power calculation. However, consulting a statistician is easier said than done simply because there are not very many statistians out there available for quick (and free of charge) consultations. It seems to be a matter of personal initiative to establish some contacts since many academic institutions don't have statisticians among their employees.

Having said that, I can't help asking myself the following when I read scientific papers: how did these authors perform statistical analysis? Did they consult a statistician? Did they do statistics themselves? What's their knowledge on this subject and did they test the hypothesis based on the correct assumptions? Did they just copy the same test from a similar paper published previously? These questions arise because in many papers only the applied test and the p value are stated. Very little or nothing is known about the assumptions for parametric testing, how the departure of the required assumptions were dealt with, possible outliers and their effect on the results, correction in multiple testing etc.

I would appreciate some input from fellow scientists so please feel free to comment on this and write your opinion. Your own or other people's experience is welcome.

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Thursday, 21 January 2010

IADR/Heraeus Travel Award

Supported by Heraeus
Deadline: February 5, 2010


The IADR is inviting applications from young investigators who have submitted an abstract which has a dental materials component for a travel award to support their attendance at the IADR General Session in 2010.

Young investigators (up to five years post-graduation from dental, material science, specialty training, or pre-PhD) are eligible to apply for a travel award. Applicants must be IADR members.

In 2010, five (5) awards will be granted—one person from each of the following regions: North America, Latin America, Europe, Africa/Middle East; and the Asia/Pacific Region. The winner of each award will receive US $2,500 for expenses to attend the IADR General Session & Exhibition in Barcelona, Spain, July 14-17, 2010.

Interested? Click HERE for more details on the application and peer-review process.

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Wednesday, 13 January 2010

Vertise Flow: the first self-adhering composite (flowable, though)


A long time ago, Michael Buonocore, one of the pioneers of adhesive dentistry, suggested four approaches to overcome the lack of adhesion between filling materials and dental tissues:
"(1) the development of new resin materials with adhesive properties;
(2) modification of present materials to make them adhesive;
(3) the use of coatings as adhesive interface materials between filling and tooth and
(4) the alteration of the tooth surface by chemical treatment to produce a new surface to which present materials might adhere." (Buonocore 1955)

In many respects, this was not only a suggestion but a visionary prediction for modern adhesive dentistry. We now know that all 4 of Buonocore's suggestions have been addressed by dental science which has led to the development of composite resins, adhesive systems and glass ionomer cements. These are three major groups of materials in adhesive dentistry today but there is a number of modifications and subgroups within each of them.

The latest news in adhesive dentistry is the development of self-adhering flowable composite, Vertise Flow by Kerr. Vertise Flow comes as a result of ongoing efforts to rationalize clinical treatment, currently including the use of adhesive systems and resin-based composites to create popular "white" fillings. Although a flowable composite, Vertise Flow clearly indicates the direction of current research by Kerr - the creation of the ultimate self-adhering composite for posterior teeth.

The manufacturer claims that Vertise Flow is based on Optibond technology which utilizes GPDM (glycero-phosphate dimethacrylate), a functional monomer, to obtain etching of enamel and dentine and HEMA, another functional monomer, most commonly used in dental adhesives to enhance wetting and resin penetration in dentine. It has been stated in many scientific papers that BisGMA is the main resin component of Optibond adhesives, though not clearly stated in manufacturer's safety data sheet. It can be expected that Vertise Flow contains BisGMA as the main cross-linking monomer as well.

One of the main questions that a dental material scientist would ask is: How does this material overcome the hydrophobic-hydrophilic mismatch between composite resins and human dentine to produce an interface that would ensure optimal bonding for long-term clinical success? This is currently achieved by the use of adhesive systems as an intermediary layer that is supposed to bridge hydrophobic composite and hydrophilic dentine.

Manufacturer's data suggest that the shear bond strength of Vertise Flow to enamel and dentine is comparable to self-etch adhesive systems. Furthermore, it is suggested that the tooth-restoration interface prevents microleakage, the passage of fluids, bacteria, molecules and ions between the restoration and cavity walls. This phenomenon has been proved to exist for all current resin-based materials due to polymerization contraction of composite resins.

Undoubtedly, Vertise Flow will soon be subjected to a vast array of studies by independent researchers that will address various properties of this material and compare it with other materials on the market. Independent evidence-based results, if in favor of this material, will be the best marketing for Vertise Flow. As always, the last word lies upon the dental practice.

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Click here to read the latest post on water sorption, solubility and dimensional changes of resin-based composites including Vertise Flow.

Free live dental webcast/webinar @ GC America Online Learning

GC I.Q.One Body Concept: The Fusion of Esthetics and Production
Presenter: Mr. Rick Sonntag, RDT

19-Jan-2010 7 pm ET (12 pm GMT)
About 150 seats available

Rick Sonntag RDT will show how production laboratories can reach their esthetic potential and how boutique labs can maximize their production potential. Viewers will also see the flexibility of the system that can be adapted to conventional layering techniques, micro-layering techniques, or internal stain techniques, on metal and zirconia.

Prior to claiming a seat for this webinar, you must create a free account at GC America Online Learning HERE.

Also, check out other free webcasts @ Pentron and Kerr
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Tuesday, 12 January 2010

Mineral Trioxide Aggregate (MTA): Free Full Text Articles I

This is the list of scientific articles on mineral trioxide aggregate (MTA) available in full text. All articles can be downloaded following the links on MEDLINE. You may also be interested in other posts on MTA. Click here for part II of the list of free full text articles on MTA.

Pulp capping

1. Bogen G, Kim JS, Bakland LK. Direct pulp capping with mineral trioxide aggregate: an observational study. J Am Dent Assoc. 2008 Mar;139(3):305-15; quiz 305-15.

2. Ford TR, Torabinejad M, Abedi HR, Bakland LK, Kariyawasam SP. Using mineral trioxide aggregate as a pulp-capping material. J Am Dent Assoc. 1996 Oct;127(10):1491-4.

Endodontics

3. Ghaziani P, Aghasizadeh N, Sheikh-Nezami M. Endodontic treatment with MTA apical plugs: a case report. J Oral Sci. 2007 Dec;49(4):325-9.

4. Winik R, Araki AT, Negrão JA, Bello-Silva MS, Lage-Marques JL. Sealer penetration and marginal permeability after apicoectomy varying retrocavity preparation and retrofilling material. Braz Dent J. 2006;17(4):323-7.

5. Witherspoon DE, Small JC, Harris GZ. Mineral trioxide aggregate pulpotomies: a case series outcomes assessment. J Am Dent Assoc. 2006 May;137(5):610-8.

6. Silberman A, Cohenca N, Simon JH. Anatomical redesign for the treatment of dens invaginatus type III with open apexes: a literature review and case presentation. J Am Dent Assoc. 2006 Feb;137(2):180-5. Review.


7. Schwartz RS, Mauger M, Clement DJ, Walker WA 3rd. Mineral trioxide aggregate: a new material for endodontics. J Am Dent Assoc. 1999 Jul;130(7):967-75. Review.

Chemical analysis

8. Oliveira MG, Xavier CB, Demarco FF, Pinheiro AL, Costa AT, Pozza DH. Comparative chemical study of MTA and Portland cements. Braz Dent J. 2007;18(1):3-7.

(The link to each article is in the top right corner as shown in this image. Click to enlarge.)


The following articles are available from PubMed Central.

Immunology

9. Taia Maria Berto Rezende, Leda Quercia Vieira, Antônio Paulino Ribeiro Sobrinho, Ricardo Reis Oliveira, Martin A. Taubman, and Toshihisa Kawai. The influence of Mineral Trioxide Aggregate (MTA) on adaptive immune responses to endodontic pathogens in mice. J Endod. 2008 September; 34(9): 1066–1071.

Tissue engineering (Genetics)

10. Paul C Edwards and James M Mason. Gene-enhanced tissue engineering for dental hard tissue regeneration: (2) dentin-pulp and periodontal regeneration. Head Face Med. 2006; 2: 16.

11. Rebecca S. Prescott, Rajaa Alsanea, Mohamed I. Fayad, Bradford R. Johnson, Christopher S. Wenckus, Jianjun Hao, Asha S. John, and Anne George. In-vivo Generation of Dental Pulp-Like Tissue Using Human Pulpal Stem Cells, a Collagen Scaffold and Dentin Matrix Protein 1 Following Subcutaneous Transplantation in Mice. J Endod. 2008 April; 34(4): 421–426.

(The link is shown in the image below. Click to enlarge.)


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Monday, 11 January 2010

Free live dental webcast/webinar @ Pentron Clinical Technologies

How, When and Why of Restorative Posts Cores
Presenter: Dr. Gregori Kurtzman, D.D.S.
Thursday 14 - Jan - 2010 at 6:00 pm ET (11 pm GMT)
About 150 seats left.Prior to claiming a seat, you must create a free account at Pentron Clinical Technologies HERE. This course is CE approved (1 CE credit). Instructions how to enter this virtual class are on the Pentron website.

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Saturday, 9 January 2010

Free live dental webcasts/webinars @ Kerr Learning Source

Register for upcoming live webcasts at Kerr Learning Source

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(1) Simplifying the Placement of Exquisite Direct Resin Restorations
Presenter: Dr. Bob Lowe

Wed 13-Jan-2010 at 7 pm ET (14-Jan-2010 midnight GMT)
About 20 seats left !!!

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(2) Simplifying Restorative Dentistry Using Self Adhesive Flowable Composites
Presenter: Dr. Martin Jablow

Wed 10-Feb-2010 at 7 pm ET (11-Feb-2010 midnight GMT)
About 170 seats left.

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Prior to claiming a seat, it is essential to create an account for free at Kerr Learning Source HERE.

Both webcasts are CE accredited (1 CE credit). All instructions on how to enter the virtual classroom and attend these live course are given on the Kerr Learning Source website.

Both webcasts are supported by Kerr Dental.

Dental materials in practice

Endodontic treatment (obturation phase): lower premolar with 3 roots by Dr Lang

Wednesday, 6 January 2010

Dental materials - online learning resources

Dental materials lectures by professors Stephen C. Bayne and Jeffrey Y. Thompson for UNC and Michigan DDS students. Other users need special permission but the files can be accessed and viewed free of charge. The lectures cover topics from operative dentistry (pulpal capping, adhesives, composites, amalgam, glass-ionomer cements), fixed prosthodontics (impression materials, waxes, alloys, ceramics) and removable prosthodontics (alloys, bases and teeth). The files are in the form of PDF and PPT handouts, self-study modules and audio files and include study and discussion questions.

University of Berkley webcasts - Structural Aspects of Biomaterials , Instructor Lisa Pruitt. Tooth and bone tissues are addressed in a basic manner necessary to understand the interaction with materials. Dental materials (filling materials, implants) are discussed in terms of mechanical and structural aspects. Mechanical design for longevity includes topics of fatigue, wear, and fracture. Very well explained and understandable to dentists without almost any previous engineering knowledge. This webcast is free to view but cannot be downloaded.

Dental materials webinars by various speakers at dentallearning.com. There are 13 webinars covering topics such as contemporary adhesives, dentine bonding , anterior and posterior composite restorations, sealants and glass ionomers, zirconia, impression materials, CEREC restorations. Among the speakers are renowned lecturers Dr David Pashley and Dr Jorge Perdigao who address the advances in adhesive dentistry and explore the science of dentine bonding. The cost of webinars by Drs Pashley and Perdigao is USD$35 whereas most other webinars direct you to Kerr Learning source where they can be viewed but registration (free) is required. There are even more free webinars at Kerr Learning. All these webinars are CE approved.

Dental ED live lectures and online courses - cost from USD$50 to USD$260. Online courses include composite restorations, endodontic obturation, dental implants, porcelain building techniques, shade selection, direct laminate veneers, zirconica restorations. Upcoming live lectures can be viewed at Dental ED website. Basically, all lectures and courses are audio-visual presentations with more or less theoretical background but with excellent clinical cases.

Sunday, 3 January 2010

Scientific journals focusing on dental materials

Two journals in the Science Citation Index (SCI) database focus exclusively on dental materials: (1) Dental Materials and (2) Dental Materials Journal.

Dental Materials is published monthly by the Academy of Dental Materials and is currently ranked 4/55 in the Dentistry, Oral Surgery & Medicine discipline and 5/19 in the Materials Science, Biomaterials discipline. Its impact factor for 2008 is 2.941. It is available through ScienceDirect but requires personal or institutional subscription for full text access. Abstracts can be accessed for free. January 2010 issue of Dental Materials is a free sample and full texts can be downloaded as PDF files. This issue is available HERE.


Dental Materials Journal is published bi-monthly by the Japanese Society for Dental Materials and Devices and is currently ranked 51/55 in the Dentistry, Oral Surgery & Medicine discipline and 15/19 in the Materials Science & Biomaterials discipline. Its impact factor for 2008 is 0.713. Dental Materials Journal is available through FreeMedical journals or at publisher's website HERE. All issues are free and full texts can be downloaded as PDF files.

Though I access full texts in most dental journals through my University online library, occasionally there are articles which cannot be obtained this way. Another way of obtaining an article in its entirety is to send a reprint request to the corresponding author. Fortunately, there is an email address attached to most abstracts on PubMed/MEDLINE. I have been able to obtain almost all articles from the authors whom I sent reprint requests. The only problem may arise when the provided email address becomes inactive. This often happens when an author changes institutions and institutional email addresses. This is why I, for example, always provide my gmail address for correspondence when submitting an article for publication.