Research in general dental practice

Performance of resin composite restorations in the primary dentition: a retrospective university-based study

BACKGROUND

Limited data is available on variables influencing the survival of composite restorations in primary teeth.

AIM

This retrospective university-based study assessed the survival and risk factors associated with failures of resin composite restorations performed in primary teeth.

DESIGN

The sample was composed of 961 restorations from records of 337 patients (178 girls and 159 boys) attended in a university dental clinic. The restorations' longevity up to 48 months of follow-up was assessed using the Kaplan-Meier survival test. Multivariate Cox regression analysis with shared frailty was used to evaluate the factors associated with failures (P < 0.05).

RESULTS

Mean survival time was 41.5 months (95% CI: 39.7-43.3), with 70.6% of the restorations surviving after 48 months of evaluation. The overall annual failure rate up to 48 months follow-up was 8.3%. Restorations placed in lower arch had lower survival rate than those in upper arch (HR: 1.82, 95% CI: 1.02-3.28). Restorations involving two or more surfaces had more risk of failure than restorations placed in cavities involving only one surface (HR: 2.55 95% CI: 1.34- 4.83). Girls had less risk of failure in their restorations (HR: 0.43, 95% CI: 0.19-0.96).

CONCLUSION

Individual and dental variables such as gender, arch type and number of restored surfaces were associated with failure of composite restorations performed in children under daily life clinical environment.

Creating research and development awareness among dental care professionals by use of strategic communication: a 12-year intervention study

Background

Despite the availability of contemporary research advances, only a limited fraction is implemented into dental practice. One possible way to facilitate this process is to stimulate the research and development (R&D) awareness and interest with aid of strategic communication.

Methods

The aim of the study was to analyse the role of a strategic communication in R&D awareness and interest among dental care professionals (DCP) over a 12-year period. A second aim was to compare the findings with those from primary care professionals (PCP). The project had a prospective design and the intervention was conducted through established oral, written and digital channels. The outcome was captured by two validated questionnaires submitted after 7 and 12 years, respectively. An additional Questionnaire file shows the details [see Additional file 1]. The material consisted of 599 health care professionals (205 DCP; 394 PCP) that responded to the first questionnaire and 526 individuals (195 DCP; 331 PCP) who responded to the second. All were employed by the primary care organization of Region Halland located in southwest of Sweden. The majority were women (≥ 85%) and the mean age at the first questionnaire was 49 years (SD 8.5). Longitudinal analyses were applied to those individuals that responded to both surveys after 7 and 12 years (n = 248). Comparisons between DCP’s and PCP’s were processed with Chi-square and Fischer’s exact tests.

Results

Strategic communication contributed to increase the R&D awareness and interest among the dental personnel. The created interest was reported stronger among the DCP when compared with PCP at both surveys (p < 0.05). The longitudinal findings confirmed a long-term interest among the DCP’s. Direct and indirect communication facilitated R&D interest in both groups. The most powerful channels were the written “Research bulletin” and peer inspiration.

Conclusion

Strategic communication can be employed as a scientific tool that may contribute to the creation of a long-term R&D awareness and interest among dental care professionals.

Electronic supplementary material

The online version of this article (10.1186/s12903-017-0445-7) contains supplementary material, which is available to authorized users.

A Three-Year Retrospective Study on Survival of Ceramic-Veneered Zirconia (Y-TZP) Fixed Dental Prostheses Performed in Private Practices

Objectives

The aim of this retrospective study was to evaluate the three-year clinical outcome for ceramic-veneered zirconia fixed dental prostheses (FDPs).

Methods

All patients who were treated with ceramic-veneered zirconia FDPs, in three private practices in Sweden, during the period June 2003 to April 2007 were included. Case records from 151 patients, treated with a total of 184 zirconia FDPs (692 units), were analysed for clinical data. All complications noted in the charts were registered and compared to definitions for success and survival and statistical analysis was performed using the Kaplan-Meier method and a Cox regression model.

Results

In total, 32 FDPs in 31 patients experienced some type of complication (17.4% of FDPs, 20.5% of patients). Core fractures occurred in two (1.1%) FDPs. Two (1.1%) FDPs or 0.6% of units showed adhesive veneer fractures. Cohesive veneer fractures occurred in 10 (5.4%) FDPs (1.6% of units). The three-year cumulative success and survival rates (CSR) were 82.3% and 95.2%, respectively.

Conclusions

Ceramic-veneered zirconia is a promising alternative to metal-ceramic FDPs, even in the posterior area. However, the higher survival rate of metal-ceramic FDPs should be noted and both dentists and patients must be aware of the risks of complications.

Dental practitioner recruitment for a randomized clinical trial in the field to evaluate the performance of a new glass ionomer restoration material

BACKGROUND

In 2009, we began recruiting dental practitioners across Germany to participate in a clinical trial to evaluate the clinical performance of EQUIA, a new glass ionomer restoration material. The aim of this paper is to discuss the outcomes of the dental practitioner recruitment and outline the process of establishing a practice-based research network.

METHODS

Study proposals were sent to randomly selected dental offices in 29 cities in Germany. The proposals were sent until a minimum of 10 clinics in each city declared participation. Later on, briefing lectures informed the participating practitioners about the design, methods, and material application procedure. Participants were familiarized with the guidelines of Good Manufacturing Practice (GMP) and Good Epidemiological Practice (GEP). A questionnaire describing the characteristics of each dental office was filled out by the participating practitioner. Additionally, participation levels were characterized according to the socioeconomic status and geographic districts of residence in Germany (Regions 0 to 9). The associations between the characteristics were tested by the Kruskal-Wallis Test and Chi-squared test (P < 0.05).

RESULTS

A total of 3194 private dental clinics were invited, 1712 clinics refused to participate, 1195 did not respond to the invitation, and 323 agreed to participate. Only 144 clinics participated in the lectures held in their cities and signed the participation agreement. Based on their geographic location, the highest participation was in Region 2 with a participation rate of 14.3%, and the lowest participation was in Region 6 with a participation rate of 1.7%. Regions with the lowest rate of unemployment and relatively higher rates of income (Regions 7 and 8) had the highest rate of refusals (86%).

CONCLUSION

The initial results of the dental practitioner recruitment in this study suggest that the recruitment and pre-randomization design were successful, and by reaching out to a considerable number of private dental clinics to participate, we were able to recruit a smaller number of highly motivated dentists in this clinical study. Regional differences in socioeconomic status, practitioner specialization, and differences in patient health care insurance have to be considered when recruiting dental practitioners for clinical trials.

TRIAL REGISTRATION

The trial has been registered at Deutsches Register Klinischer Studien (German register of clinical trials) on 6 September 2012 under DRKS-ID: DRKS00004220.

Three-year outcomes of root canal treatment: Mining an insurance database

OBJECTIVES

There is doubt whether success rates of root canal treatments reported from clinical trials are achievable outside of standardized study populations. The aim of this study was to analyse the outcome of a large number of root canal treatments conducted in general practice.

METHODS

The data was collected from the digital database of a major German national health insurance company. All teeth with complete treatment data were included. Only patients who had been insurance members for the whole 3-year period from 2010 to 2012 were eligible. Kaplan-Meier survival analyses were conducted based on completed root canal treatments. Target events were re-interventions as (1) retreatment of the root canal treatment, (2) apical root resection (apicoectomy) and (3) extraction. The influences of vitality status and root numbers on survival were tested with the log-rank test.

RESULTS

A total of 556,067 root canal treatments were included. The cumulative overall survival rate for all target events combined was 84.3% for 3 years. The survival rate for nonvital teeth (82.6%) was significantly lower than for vital teeth (85.6%; p<0.001). The survival rate for single rooted teeth (83.4%) was significantly lower than for multi-rooted teeth (85.5%; p<0.001). The most frequent target event was extraction followed by apical root resection and retreatment.

CONCLUSIONS

Based on these 3-year outcomes, root canal treatment is considered a reliable treatment in practice routine under the conditions of the German national health insurance system.

CLINICAL SIGNIFICANCE

Root canal treatment can be considered as a reliable treatment option suitable to salvage most of the affected teeth. This statement applies to treatments that in the vast majority of cases were delivered by general practitioners under the terms and conditions of a nationwide health insurance system.

The efficacy of a specific stabilization splint

BACKGROUND

The use of a Tanner type stabilization splint, fabricated on a leaf gauge articulation for the treatment of patients with disc displacement without reduction, is lacking in the literature.

OBJECTIVES

The purpose of the study is to collect non-controlled, therapy-related observations; in other words, to demonstrate the efficacy of this appliance for the treatment of patients with disc displacement without reduction.

METHODS

The study enrolled 55 patients, 5 men, and 50 women, with the clinical diagnosis disc displacement without reduction, 42 with and 13 without limited mouth opening. All patients received a splint in the musculoskeletally stable centric relation (CR) position. Mouth opening, clinical performance, and the timeframe of splint treatment were assessed.

RESULTS

For 37 patients with a disc displacement without reduction with limited opening, the largest increase in mouth opening (9.5 +/- 5.6 mm) occurred in the first week (7.9 +/- 2.5 days). No occlusal adjustment of the splint was needed during the treatment sequence. For three patients, treatment took up to 3 months (8.1%), for 13 patients, between 3 and 6 months (35.1%), and for 17 patients, within a year (45.9%), making a total of 89.1% successfully treated patients. Out of 50 patients, 29 had a total resolution of signs and symptoms, whereas 21 patients still suffered from solitary temporomandibular disorder (TMD) signs.

CONCLUSION

A Tanner type stabilization splint, fabricated in the musculoskeletally stable CR position, appears to be an effective and efficient means for the treatment of patients with disc displacement without reduction. Its efficacy makes it eligible to be tested in a randomized controlled trial.

CLINICAL IMPLICATIONS

The efficacy of this specific splint, fabricated in the musculoskeletally stable CR position, makes it a promising tool to treat TMD patients with disc displacement without reduction.

Patient Risk Factors’ Influence on Survival of Posterior Composites

This practice-based retrospective study evaluated the survival of resin composite restorations in posterior teeth, focusing on the influence of potential patient risk factors. In total, 306 posterior composite restorations placed in 44 adult patients were investigated after 10 to 18 yrs. The history of each restoration was extracted from the dental records, and a clinical evaluation was performed with those still in situ. The patient risk status was assessed for caries and “occlusal-stress” (bruxism-related). Statistical analysis was performed by the Kaplan–Meier method and Cox-regression multivariate analysis. In total, 30% of the restorations failed, of which 82% were found in patients with 1 or 2 risk factors. Secondary caries was the main reason of failure within caries-risk patients, whereas fracture was the main reason in “occlusal-stress-risk” patients. The patient variables gender and age did not significantly affect survival, but risk did ( p < .001). Tooth type ( p < .001), arch ( p = .013), and pulpal vitality ( p = .003) significantly affected restoration survival. Within the limits of this retrospective evaluation, the survival of restorations is affected by patient risk factors, which should be included in survival analyses of restorations.

Reasons for replacement of restorations: dentists' perceptions

OBJECTIVE

This study aimed at evaluating dentists' perceived reasons for replacement of restorations and ascertaining the differences arising from dentists' gender, time since graduation and working sector (salaried vs private).

MATERIALS AND METHODS

A postal questionnaire was sent to a total of 592 working-age general dental practitioners in Finland, 57% (n = 339) responded. The dentists were asked to rank in order of priority the six most common reasons for replacement of composite in the incisors and posterior teeth and amalgam in the posterior tooth from a list of 12 reasons. Ranking order 1 was worth six points and order 6 one point; the non-ranked reasons were equal to zero. Differences in the means of the summed scores of caries-related (RC), fracture- and failure-related (RF) and miscellaneous (RO) groups were evaluated by ANOVA. The level of significance was set at p = 0.05.

RESULTS

For each of three restorations, the RF group comprised 48-56% of the sum-scores. Of the single reasons, secondary caries predominated (20-24%). For composite restorations in the incisors, the mean sum-score of the RO group was greater for private-sector dentists (p = 0.04). For composite restorations in the posterior teeth, the mean sum-score of RF group was higher for male than female dentists (p = 0.009). For amalgam, mean score for RF was 10.2, followed by RC (8.5) and RO (1.1).

CONCLUSION

Secondary caries and various fractures and failures predominate as dentists' perceived reasons for replacement of restorations. Private dentists included miscellaneous reasons as one of their six reasons more often than did the salaried dentists. The complex process of treatment planning and decision-making is influenced by many as of yet unknown factors, calling for emphasis on investigating of perceptions.

Statistical errors in microleakage studies in operative dentistry. A survey of the literature 2001-2009

The aim of this study was to assess the literature on microleakage of direct restorations in operative dentistry indexed in the ISI Web of Science, in order to assess the robustness of the statistical methodology used. Our database included 226 scientific papers (published between 2001 and 2009 in 22 journals) from the journal citation report categories 'Dentistry, Oral Surgery and Medicine' and 'Materials Science, Biomaterials'. We reviewed all articles to find potential mistakes that are commonly made at different stages in the scientific research process. Microleakage was assessed quantitatively in 50 (22.2%) studies and qualitatively in 176 (77.8%) studies. In all studies reviewed the statistical methods used were appropriate for the category attributed to the outcome variable, but in 13% of the total, the chi-square test or parametric methods were inappropriately used afterwards. When the appropriate statistical methods were applied in studies that had originally employed inappropriate methods to analyse their data, and in which the authors provided raw data, an alteration of the conclusions was necessary in 15.4% of these re-analysed studies. This survey also showed that the statistical methodology applied varies considerably for similar experimental designs. This could have an effect on statistical results; hence, a more standardized methodology should be implemented.

A qualitative investigation of the views of primary care dentists on participating in prospective studies in the North-West of England

BACKGROUND

There is a poor understanding of to how to recruit and involve primary care dentists in clinical trials.

AIM

To use a qualitative paradigm to explore the views of primary care dentists towards participating in clinical trials and develop an understanding of the factors that facilitate and prevent their involvement. DESIGN, SETTING, SUBJECTS AND METHODS: An iterative approach was undertaken using a focus group (n = 6) followed by phased semi-structured interviews (n = 18). Data were analysed using thematic analysis and constant comparative analysis.

FINDINGS

The semi-structured interviews generated nine codes which were organised into three themes: technical issues for trials in primary dental care, practical issues for research in primary dental care and primary care dentists as research consumers. Overall, primary care dentists had a poor understanding of research methodology and clinical research. Barriers to participation included loss of clinical freedom and control, practice disruption, patient welfare, staff workload, financial loss and time.

CONCLUSIONS

Barriers to primary dental care research need to be overcome through appropriate protocols, funding, training and support. Joint working of primary dental care teams and academic researchers is essential, along with a constructive and open dialogue, if clinical trials are to be successfully undertaken in a practice environment.

How primary care dentists perceive and are influenced by research

INTRODUCTION

Little is understood as to how primary care dentists alter their clinical practice.

AIM

To develop an understanding of how primary care dentists view and use research to inform their clinical practice.

METHODS

An iterative approach was followed using two methods of data collection. A focus group was undertaken with dentists and researchers who had been involved in primary care dental research. Subsequently phased, qualitative interviews were undertaken with primary care dentists with a range of research experiences. Focus group and interviews were audio-recorded and transcribed verbatim. Six people participated in the focus group. Eighteen dentists participated in the interviews. Interviews were undertaken in four phases until saturation was achieved. Data were analysed using constant comparison.

FINDINGS

Evidence-based dentistry was considered the ideal. However, the research base for primary care dentistry was thought to lag behind clinical services, to focus on incorrect endpoints, to disregard the patients' voice and failed to consider the impact of conducting research on dental practices. Dentists modified their clinical practice based upon research, colleagues' opinions, courses and ad hoc personal evaluation. Uptake of research was affected by the ethos of the practice, which determined whether the dentists were early or late adopters of research and financial viability of new interventions.

CONCLUSION

  Dentists wanted concise, timely evidence-based guidance to aid their management of patients. Further research needs to be undertaken to understand how to develop an evidence-based culture in primary dental care.

Dissemination tools and resources: assisting colleagues in the implementation and promotion of EBD principles

Many resources and methods are available for dissemination and promotion of the principles and value of evidence-based dentistry among colleagues.

Comparison of the effectiveness of fissure sealants in Finland, Sweden, and Greece

OBJECTIVE

To evaluate the effectiveness of sealant treatment in preventing dental restorations due to caries in a practice-based research network in Finland, Sweden, and Greece.

MATERIAL AND METHODS

Times of tooth emergence, sealing treatment, and dental caries were compiled from the dental charts of 4735 subjects born in 1970-72 in Finland and in 1980-82 in Finland, Sweden, and Greece. Survival time between tooth emergence and placement of first restoration was measured and estimated using survival analysis methodology.

RESULTS

At the end of follow-up (7-10+ years), 30-40% of sealed molars and 60-80% of non-sealed molars were restored. Early sealant placement compared to late sealing did not result in significantly higher survival of 1st molars. The strategy of sealing the 1st molars only in high caries risk subjects was as effective as sealing all the molars and premolars routinely without caries risk determination.

CONCLUSIONS

The sealing of all molar fissures proved to be no more effective than sealing risk fissures of subjects. Early sealing did not result in any better outcome than late sealing. The effectiveness of sealant treatment in preventing dental restorations is dependent on the caries risk of individuals and caries prevalence of the country.

Computed online determination of life-long mean index values for carious, extracted, and/or filled permanent teeth

OBJECTIVE

The purpose of this study was to develop and test a data-mining system for the online determination of mean DS, M, and FS or DMFS values per subject at different ages from electronic patient records at two health centers to see if there are north-south differences in oral health in Finland.

MATERIAL AND METHODS

The mean index values were determined at two health centers using the codes of dental charts and progress notes of electronic dental records during the digital era of more than 10 years in a total of 153,619 subjects of all ages. Extracted teeth, as well as sound, carious, and restored tooth surfaces, were recorded from the dental charts. Treatments were then additionally registered from progress notes of the records when performed.

RESULTS

The cumulative DS and FS values were similar in subjects under the age of 20 years at both health centers. In adults, caries was more abundant in northern Finland, where there was a higher number of restored surfaces (>40) registered, compared to only 30 in southern Finland at the age of 40 years. A high increase in the number of extractions began at age 45 in the north compared to age 70 in the south. These changes were clearly reflected in the DMFS index.

CONCLUSIONS

Online determination of health parameters is a feasible methodology. The results revealed that north-south regional differences in dental health still occur in adults in Finland, but not in subjects younger than 20 years of age.

Long-term follow-up of composite resin restorations with self-etching adhesives

OBJECTIVE

To test the hypothesis, derived from a previous short-term (7-day) assessment, that the absence of conventional pulp protection is not responsible for long-term pulp complications of composite resin restorations with self-etching adhesives.

METHODS

All 150 patients who received the restorations with self-etching adhesives were recalled at least 2 years after the placement of restorations. Of the 47 patients (31%) who responded, 106 restorations aged from 2.2 to 6.5 years were examined for tooth sensitivity and pulp vitality regarding long-term pulp complications. The results were subjected to a multivariable logistic regression analysis with regard to cavity depth, provision of conventional pulp protection and short-term pulp complications.

RESULTS

No positive cases were found in the assessment of tooth sensitivity. Four restorations (3.7%) made in deep cavities with conventional pulp protection resulted in pulpectomy due to inflammation, of which three cases presented short-term pulp complications. The 95% confidence intervals for the odds ratios estimated by the multivariable logistic regression analysis were (1.54, infinity) for cavity depth (1.50, infinity) for short-term pulp complications and (0.02, infinity) for conventional pulp protection. Namely, the last variable had no significant effect on long-term pulp complications and thus the hypothesis was verified.

CONCLUSIONS

The absence of conventional pulp protection was not responsible for long-term pulp complications even in deep cavities with the use of self-etching adhesives. A deep cavity and the existence of short-term pulp complications were two critical predictors for the occurrence of long-term pulp complications.

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.

Oral health and morbidity--implications of oral infections on the elderly

Detrimental effects of oral infections on general health have been known for almost 3000 years. Modern studies, however, have cast new light on the pathogenic mechanisms by which oral infections appear to link with morbidity and mortality. In particular, among the elderly, poor dental health seems to associate with all-cause mortality. This review aims to provide an overview of present knowledge of these issues, starting from dental bacteraemia, oral mucosal infections and problems of drug resistance and, briefly, discussing what is known about the link between oral health and some systemic diseases such as atherosclerosis and type-2 diabetes. The main conclusions are that scientific evidence is still weak on these interactions and that the elderly should be better taken into account when planning future studies. Functions of the body differ in the frail and diseased from those of the young. Consequently, novel prevention and treatment strategies should be developed and properly tested for combating oral infections in elderly populations. Specific suggestions for further research are outlined.