12 Years of Repair of Amalgam and Composite Resins: A Clinical Study.

OBJECTIVE: The objective of this study was to clinically evaluate repaired posterior amalgam and composite restorations over a 12 year period, investigate the influence of repair in the survival of restorations, and compare their behavior with respect to controls. METHODS: Thirty-four patients, 18 to 80 years of age with 167 restorations, 67 composite resin (RC), and 100 amalgam (AM) restorations, participated. Restorations with localized, marginal, anatomical deficiencies and/or secondary caries, and "clinically judged" suitable for repair or replacement according to US Public Health Service (USPHS) criteria, were randomly assigned to four groups: repair (n=35, 20 AM, 15 RC), replacement (n=43, 21 AM, 22 RC), positive control (n=71, 49 AM, 22 RC), or negative control (n=18, 10 AM, 8 RC). The quality of the restorations was blind scored according to the modified USPHS criteria. Two examiners scored them at initial status (κ=0.74) and after one to five, 10, and 12 years (κ=0.88). Wilcoxon and Mann-Whitney tests provided for comparisons within the same group and between years, respectively. RESULTS: After 12 years, all groups behaved similarly in marginal adaptation, marginal stain, teeth sensitivity, anatomic form, and luster ( p≥0.05). Better behavior in roughness was observed in replaced RC ( p=0.049). CONCLUSIONS: Given that most clinical parameters investigated were similar between all groups during the follow-up, the repair of RC and AM restorations is a good clinical option because it is minimally invasive and can consistently increase the longevity of restorations.

Effect of Refurbishing Amalgam and Resin Composite Restorations After 12 Years: Controlled Clinical Trial.

OBJECTIVES: The aim of this study was to clinically evaluate posterior amalgam and resin composite restorations refurbished over a period of 12 years by investigating the influence of refurbishing on the survival of restorations and comparing their behaviors with respect to controls. METHODS AND MATERIALS: Thirty-four patients were enrolled, ages 18 to 80 years, with 174 restorations, 48 restorations of resin composite (RC), and 126 restorations of amalgam (AM). Restorations with localized defects in anatomy, roughness, luster, or marginal staining that were clinically judged as suitable for refurbishing according to US Public Health Service (USPHS) Ryge criteria were assigned to group A-refurbishing (n=85; 67 AM, 18 RC)-or group B-control (n=89; 59 AM, 30 RC); the quality of the restorations was evaluated blindly according to the modified USPHS criteria. Two observers conducted evaluations at the initial state (k=0.74) and after one to five, 10, and 12 years (k=0.88). Wilcoxon, Friedman, and Mantel-Cox tests were performed to compare the groups, respectively. RESULTS: After 12 years, both groups experienced a similar decline, except for an evidently better performance in marginal adaptation in RC control (p=0.043) and in anatomy in AM refurbished (p=0.032). CONCLUSIONS: After 12 years, no difference was found in the clinical condition and longevity of the refurbished restorations compared to the control group.

Seal, replacement or monitoring amalgam restorations with occlusal marginal defects? Results of a 10-year clinical trial.

The aim of this prospective and blind clinical trial was to assess the effectiveness of sealing localized marginal defects of amalgam restoration that were initially scheduled to be replaced. A cohort of twenty six patients with 60 amalgam restorations (n=44Class I and n=16Class II), that presented marginal defects deviating from ideal (Bravo) according to USPHS criteria, were assigned to either sealing or replacement groups: A: sealing n=20, Replacement n=20, and no treatment (n=20). Two blind examiners evaluated the restorations at baseline (K=0.74) and after ten years (K=0.84) according with USPHS criteria, in four parameters: marginal adaptation (MA), secondary caries (SC), marginal staining (MS) and teeth sensitivity (TS). Multiple comparison of restorations degradation/upgrade was analyzed by Friedman test and the comparisons within groups were performed by Wilcoxon test. After 10 years, 44 restorations were assessed (73.3%), Group A: n=14 and Group B: n=16; and Group C: n=14 sealing and replacement amalgam restorations presented similar level of quality in MA (p=0.76), SC (p=0.25) and TS (p=0.52), while in MS (p=0.007) presented better performance in replacement group after 10-years. Most of the occlusal amalgam restorations with marginal gaps showed similar long term outcomes than the restorations were sealed, replaced, or not treated over a 10-year period. Most of the restorations of the three groups were clinically acceptable, under the studied parameters. All restorations had the tendency to present downgrade/deterioration over time.

Longitudinal results of a 10-year clinical trial of repair of amalgam restorations.

The aim of this prospective, blind, and randomized clinical trial was to assess the effectiveness of repair of localized clinical defects in amalgam restorations that were initially scheduled for replacement. A cohort of 20 patients with 40 (Class I and Class II) amalgam restorations that presented one or more clinical features that deviated from the ideal (Bravo or Charlie) according to US Public Health Service criteria, were randomly assigned to either the repair or the replacement group-A: repair, n = 19; and B: replacement, n = 21. Two examiners who had calibration expertise evaluated the restorations at baseline and 10 years after according to seven parameters: marginal occlusal adaptation, anatomic form, surface roughness, marginal staining, contact, secondary caries, and luster. After 10 years, 30 restorations (75%) were evaluated (Group A: n = 17; Group B: n = 13). Repaired and replaced amalgam restorations showed similar survival outcomes regarding marginal defects and secondary caries in patients with low and medium caries risk, and most of the restorations were considered clinically acceptable after 10 years. Repair treatment increased the potential for tooth longevity, using a minimally interventional procedure. All restorations trend to downgrade over time.

Minimal invasive treatment for defective restorations: five-year results using sealants.

Replacement of dental restorations has been the traditional treatment for restorations that are defective. In this five-year randomized clinical trial, restorations with localized marginal defects were treated with sealants. Thirty-two patients (mean age, 26.8 years) with 126 Class I and Class II restorations with defective margins (amalgam n=69 and resin-based composite n=57) were recruited. Treatment was seal with pit and fissure sealant on localized marginal defects (group A: n=43) and was compared with total restoration replacement (group B: n=40) and untreated restorations (group C: n=43) as negative and positive controls. Restorations were assessed by two examiners using the modified US Public Health Service criteria, observing five clinical parameters: marginal adaptation, roughness, marginal stain, teeth sensitivity, and secondary caries at baseline and at five years after treatment. At the five-year recall examination, 23 patients with 90 restorations (71.4% recall rate) were examined. A significant improvement was observed in the marginal adaptation of the restorations in group A compared with group B. None of the treated group showed trends to downgrade in any parameter. Tooth sensitivity and secondary caries showed a low frequency in all groups. No significant difference in marginal adaptation of the restorations was found between amalgam and resin-based composite restorations (p=0.191). This study demonstrated that marginal sealing of restorations is a minimally invasive treatment that may be used instead of the replacement of restorations with localized marginal defects.

Repair of dimethacrylate-based composite restorations by a silorane-based composite: a one-year randomized clinical trial.

PURPOSE: To investigate clinical performance of a low-shrinkage silorane-based composite resin when used for repairing conventional dimethacrylate-based composite restorations. BACKGROUND: Despite the continued development of resin-based materials, polymerization shrinkage and shrinkage stress still require improvement. A silorane-based monomer system was recently made available for dental restorations. This report refers to the use of this material for making repairs and evaluates the clinical performance of this alternative treatment. MATERIALS AND METHODS: One operator repaired the defective dimethacrylate-based composite resin restorations that were randomly assigned to one of two treatment groups: control (n=50) repair with Adper SE Plus (3M/ESPE) and Filtek P60 Posterior Restorative (3M/ESPE), and test (n=50) repair with P90 System Adhesive Self-Etch Primer and Bond (3M/ESPE) and Filtek P90 Low Shrink Posterior Restorative (3M/ESPE). After one week, restorations were finished and polished. Two calibrated examiners (Kw≥0.78) evaluated all repaired restorations, blindly and independently, at baseline and one year. The parameters examined were marginal adaptation, anatomic form, surface roughness, marginal discoloration, postoperative sensitivity, and secondary caries. The restorations were classified as Alpha, Bravo, or Charlie, according to modified US Public Health Service criteria. Mann-Whitney and Wilcoxon tests were used to compare the groups. RESULTS: Of the 100 restorations repaired in this study, 93 were reexamined at baseline. Dropout from baseline to one-year recall was 11%. No statistically significant differences were found between the materials for all clinical criteria, at baseline or at one-year recall (p>0.05). No statistically significant differences were registered (p>0.05) for each material when compared for all clinical criteria at baseline and at one-year recall. CONCLUSIONS: The hypothesis tested in this randomized controlled clinical trial was accepted. After the one-year evaluations, the silorane-based composite exhibited a similar performance compared with dimethacrylate-based composite when used to make repairs.

Minimum requirements for new dental materials.

A brief review of the development of standards for testing and certification of dental materials is presented. The tests employed in the standards are not correlated for the clinical use of the materials, nor to the reasons for failures of the materials. They are, therefore, of limited value for the selection of materials to be used in practice but they are important for quality control of the manufacture of the materials. Previous certification programmes are being discontinued. The responsibility for selecting safe and efficient materials is transferred to the clinicians whereas making safe and efficient materials still is the responsibility of the manufacturers.

Practice-based dental research.

Practice-based research networks have existed in medicine for many years, but they are relatively new in dentistry. Practice-based dental research is carried out in the 'real world' setting of dental practice. It encounters many problems, especially related to the clinicians' treatment decisions and their variations in assessments of clinical quality. Practice-based dental research networks have been active in Europe for the last 10-15 years and new practice-based dental research networks have recently been funded in the USA. They have been charged with the establishment of networks to carry out short-term clinical studies that have been proposed by clinicians to solve the problems they encounter in daily clinical practice. Data sharing and communication within and among the networks and with the dental community at large are a primary goal to become successful and optimally serve dental practice. A secondary goal is to conduct chart reviews on disease and treatment patterns and obtain estimates of the prevalence of less common conditions. An outline of a possible establishment of a research network is presented and the potential to institute a programme for practice-based testing of dental materials and procedures is suggested.

Recommendations for conducting controlled clinical studies of dental restorative materials.

About 35 years ago, Ryge provided a practical approach to evaluation of clinical performance of restorative materials. This systematic approach was soon universally accepted. While that methodology has served us well, a large number of scientific methodologies and more detailed questions have arisen that require more rigor. Current restorative materials have vastly improved clinical performance and any changes over time are not easily detected by the limited sensitivity of the Ryge criteria in short term clinical investigations. However, the clinical evaluation of restorations not only involves the restorative material per se but also different operative techniques. For instance, a composite resin may show good longevity data when applied in conventional cavities but not in modified operative approaches. Insensitivity, combined with the continually evolving and non-standard investigator modifications of the categories, scales, and reporting methods, has created a body of literature that is extremely difficult to meaningfully interpret. In many cases, the insensitivity of the original Ryge methods is misinterpreted as good clinical performance. While there are many good features of the original system, it is now time to move to a more contemporary one. The current review approaches this challenge in two ways: (1) a proposal for a modern clinical testing protocol for controlled clinical trials, and (2) an in-depth discussion of relevant clinical evaluation parameters, providing 84 references that are primarily related to issues or problems for clinical research trials. Together, these two parts offer a standard for the clinical testing of restorative materials/procedures and provide significant guidance for research teams in the design and conduct of contemporary clinical trials. Part 1 of the review considers the recruitment of subjects, restorations per subject, clinical events, validity versus bias, legal and regulatory aspects, rationales for clinical trial designs, guidelines for design, randomization, number of subjects, characteristics of participants, clinical assessment, standards and calibration, categories for assessment, criteria for evaluation, and supplemental documentation. Part 2 of the review considers categories of assessment for esthetic evaluation, functional assessment, biological responses to restorative materials, and statistical analysis of results. The overall review represents a considerable effort to include a range of clinical research interests over the past years. As part of the recognition of the importance of these suggestions, the review is being published simultaneously in identical form in both the "Journal of Adhesive Dentistry" and the "Clinical Oral Investigations." Additionally an extended abstract will be published in the "International Dental Journal" giving a link to the web full version. This should help to introduce these considerations more quickly to the scientific community.

Resin composite reinforcement of undermined enamel.

Studies have suggested that fracture resistance of undermined enamel increases when supported by a layer of bonded composite. Composite to reinforce enamel must have a secure foundation in dentin and/or enamel that is supported by dentin to perform optimally. A restorative technique is presented using resin composite material to support and reinforce undermined enamel that lacks dentinal support in traditional amalgam restorations. This technique is intended to conserve unsupported enamel cavity walls and weakened cusps in extensive Class I and II preparations.

Remaining dentine thickness and human pulp responses.

AIM: To evaluate pulp responses as a function of remaining dentine thickness (RDT) of 98 class V cavity preparations in 49 teeth of 31 patients aged 10-16 years. METHODOLOGY: Shallow cavities were restored with amalgam, deeper cavities or pulp exposures were restored with amalgam lined with calcium hydroxide or with zinc oxide eugenol. Teeth were extracted after 3-89 days for orthodontic reasons. Following processing for light microscope analysis, the number of odontoblasts, pulp inflammation, and repair was recorded. RESULTS: In comparison with independent odontoblasts, the numbers of odontoblasts were reduced by 13.6% beneath a RDT of 2.5-0.5 mm, 33.7% beneath a RDT of 0.5-0.01 mm and 99.0% beneath pulp-exposed cavities. Reparative dentine was observed following pulp exposure and reactionary dentine was observed with a mean RDT of 0.77 mm (2.5-0.01 mm). Reactionary dentine secretion was influenced by RDT and restorative materials. Pulp inflammation was not influenced by RDT in the present study. CONCLUSIONS: Cavity RDT mediates a powerful influence on underlying pulp tissue vitality but it has little effect on reactionary dentine secretion and inflammatory activity. Gross tissue injury explains the poor pulp capping prognosis following exposure and underlies the need to avoid this type of injury. Following restoration, a RDT of 0.5 mm or greater is necessary to avoid evidence of pulp injury.

The repair of direct composite restorations: an international survey of the teaching of operative techniques and materials.

This article reports the findings of a study on the aspects of the teaching of repair as a conservative alternative to the replacement of failing direct composite restorations (DCRs) in primary dental degree curricula in the UK and Ireland, Germany and Scandinavia. Data on teaching, including operative techniques applied in the repair of DCRs, were collected by means of a questionnaire sent to 58 dental schools in the surveyed countries. Based on the overall response rate of 83%, the findings indicate that the majority (59%) of the schools in the countries surveyed may be found to teach the repair of DCRs. However, marked variations were observed in respect of this teaching and the expected longevity of repaired DCRs. Where the repair of DCRs was not taught, views differed as to the intentions, if any, to include this teaching in the curriculum. It is concluded that the teaching of DCRs may be found to be widespread in dental schools in the UK and Ireland, Germany and Scandinavia, with this teaching being subjected to considerable variation within and between countries.

Failure, repair, refurbishing and longevity of restorations.

The clinical diagnosis of secondary caries is the main reason for replacement of all types of directly-placed restorations. This is an ill-defined clinical diagnosis both in teaching programs and in general practice. The criteria for the diagnosis must be improved and come in line with those for primary caries. Secondary caries are usually localized and delineated lesions and should be differentiated from stained and ditched margins. Small defects of secondary caries, stained and degraded margins may be removed by refurbishing/refinishing procedures. Larger defects may be explored by removing part of the restoration to access the defective margin. By removing part of the restoration to the full depth, a firm diagnosis can be made regarding the extent of the lesion, as the defects are often well delineated. Provided the main part of the restoration is satisfactory, the "exploratory" cavity preparation can then be filled with an appropriate material. These approaches will save tooth structure and be cost-effective. However, longevity data are lacking with such studies in progress.

Influence of the method of funding on the age of failed restorations in general dental practice in the UK.

OBJECTIVE: This study examined the effect of the method of funding treatment on the age of restorations at the time of replacement. METHOD: A group of general dental practitioners were recruited to take part in the study. Each participant was asked to record the reason for placement and replacement of restorations. The age and class of the restoration being replaced was also recorded, together with details of the material being used and the material being replaced. Details of the method of payment of the failed restoration were recorded. RESULTS: Details of the reason for placement/replacement were received for 3,196 restorations from 32 GDPs. Of the restorations placed, 54% were amalgam, 32% composite, 8% compomer and 7% glass ionomer. The age of restorations at the time of replacement was significantly associated with the method of payment for the restoration, with restorations placed in the Armed Forces having been in service significantly longer at the time of their replacement than restorations placed under NHS regulations. CONCLUSION: Statistical analysis indicated that restorations placed within the NHS regulations were replaced at a significantly lower age than restorations placed under the other funding arrangements investigated.

Placement and replacement of restorations in general dental practice in Iceland.

Ninety-one Icelandic practicing dentists (51% response rate) provided information related to the reasons for placement and replacement of 8,395 restorations and 741 sealants in 5,997 patients. Information included the patient's gender and age, the clinician's gender and experience in years since graduation, the defined criteria for replacement of restorations, the estimated past use of material in five-year increments and the records of 100 consecutively placed restorations. The materials used include composite (52.7%), amalgam (29.2%), glass ionomer (9.5%), resin-modified glass ionomer (7.1%) and other materials (1.4%). Although material selection was independent of the clinician's gender, female patients received more composite and fewer amalgam restorations than their male counterparts. Reasons for placing restorations comprised replacement of failed restorations (47.2%), primary caries (45.3%) and non-carious defects (7.5%). Secondary caries was the main reason for replacement for all types of restorations. Chi square analysis related to the dependence between the reasons for replacement and clinician's experience showed that more experienced clinicians recorded a lower frequency of secondary caries than less experienced ones (p<0.0001), while the diagnoses of discoloration and fracture of restorations increased with the clinicians' experience (p<0.0001).

The teaching of Class I and II restorations in primary molars: a survey of North American dental schools.

PURPOSE: The purpose of this study was to obtain an overview of materials and restoratives techniques taught for Class I and Class II restorations in primary molars in different pediatric dentistry departments in North America. METHODS: A form with response alternatives was mailed to 63 dental schools in the United States and Canada. The forms were addressed to the chairman/undergraduate program director of the department of pediatric dentistry. Questions regarding the restorative materials taught, indications and contraindications for the use of tooth-colored materials and the type of cavity preparation indicated for those materials were among the topics assessed. RESULTS: Eighty-six percent of the dental schools responded to the survey. Amalgam continues to be the material of choice for Class I and II restorations in primary molars, although hybrid composites and compomers are gaining some popularity. When tooth-colored materials were indicated, the slot-type of cavity preparation was the preferred one. CONCLUSIONS: The diversity in teaching may reflect uncertainty related to requirements for optimal restorations of primary teeth. Data from dental schools of other countries may be important to obtain to establish universally accepted criteria and standards for restorative techniques of primary teeth.

Pulp-dentin biology in restorative dentistry. Part 4: Dental caries--characteristics of lesions and pulpal reactions.

The infectious disease dental caries results in lesions that may affect enamel, dentin, pulp, and cementum. If a caries lesion has progressed to the stage at which it requires restorative intervention, it is important that the clinician understand the tissue changes in the dentin that are likely to have taken place during lesion development. Until the present, no major distinction between the restorative treatment of active (rapidly progressing) and arrested (slowly progressing) lesions has been made, despite the fact that the two conditions exhibit major differences in tissue changes in the pulp-dentin complex. Intratubular changes and tertiary dentin formation will affect the outcome of the restorative treatment. In unaffected dentin and in rapidly progressing lesions, permeable tubules persist, and when the preparation of carious teeth results in the opening of unaffected dentin, greater care must be taken in all phases of the restorative procedures than if the dentin is impermeable. An active, deep lesion can be changed to an arrested lesion by a two-step excavation approach. Optimal assessment of the prevailing clinical conditions can only be made on the basis of thorough knowledge of the biology of the pulp-dentin organ.

Current teaching of cariology in North American dental schools.

All 65 dental schools in the United States and Canada were contacted to obtain information relevant to their cariology teaching effort, the caries management philosophy, the diagnostic threshold for surgical intervention and the non-surgical treatment alternatives implemented. Forty-three schools (66%) responded to the request for information. Marked variations in the teaching of cariology and the implementation of modern diagnostic and treatment modalities were noted. The results indicate that with exceptions, efforts to increase curricular time and make organizational changes that would promote cariology as an important academic and clinical endeavor have fallen far short of predictions made more than 20 years ago for North America. Many cariology programs in North American dental schools lack the detail and depth expected for this important area of clinical dentistry.