FaceBase 3: analytical tools and FAIR resources for craniofacial and dental research.

The FaceBase Consortium was established by the National Institute of Dental and Craniofacial Research in 2009 as a 'big data' resource for the craniofacial research community. Over the past decade, researchers have deposited hundreds of annotated and curated datasets on both normal and disordered craniofacial development in FaceBase, all freely available to the research community on the FaceBase Hub website. The Hub has developed numerous visualization and analysis tools designed to promote integration of multidisciplinary data while remaining dedicated to the FAIR principles of data management (findability, accessibility, interoperability and reusability) and providing a faceted search infrastructure for locating desired data efficiently. Summaries of the datasets generated by the FaceBase projects from 2014 to 2019 are provided here. FaceBase 3 now welcomes contributions of data on craniofacial and dental development in humans, model organisms and cell lines. Collectively, the FaceBase Consortium, along with other NIH-supported data resources, provide a continuously growing, dynamic and current resource for the scientific community while improving data reproducibility and fulfilling data sharing requirements.

Secondary Caries in situ Models: A Systematic Review.

In situ caries research serves as a bridge between clinical research and laboratory studies. In this kind of research, volunteers wear a removable intraoral splint or prosthesis containing research samples. Many different in situ models exist to investigate secondary caries. This systematic review compared currently existing secondary caries models and their lesion progression per day values. MATERIALS AND METHODS: Three databases (Medline, Embase, and Cochrane) were searched for relevant literature. Bias risk was assessed and model parameters and caries-related outcomes were extracted by 2 independent researchers. Where possible, caries-related outcomes were normalized by estimating lesion progression per day by dividing lesion depth extracted from microradiographic or microhardness data by the number of days the study lasted. RESULTS: The literature search identified 335 articles. After eliminating duplicates and selection, 31 articles were included. The models differed greatly on factors such as sample location, presence of fluoride in the model, and analysis methods. Three main groups could be identified by sample placement; 68% of models placed samples palatally in the upper jaw, and the lower jaw model could be divided into the buccal (26%) and approximal (6%) areas. Average lesion progression in enamel next to composite was 4.3 ± 2.8 µm (range1.1-8.8 µm/day). DISCUSSION: Studies conducted with palatal models showed caries progression rates 2-5 times higher than the estimated clinical progression rates. Lesion progression per day could be a useful tool for future comparison of models and establishing a standardized model.

Use and misuse of mixed methods in population oral health research: A scoping review.

BACKGROUND: Despite the known benefits of a mixed methods approach in health research, little is known of its use in the field of population oral health. OBJECTIVE: To map the extent of literature using a mixed methods approach to examine population oral health outcomes. METHODS: For a comprehensive search of all the available literature published in the English language, databases including PubMed, Dentistry and Oral Sciences Source (DOSS), CINAHL, Web of Science and EMBASE (including Medline) were searched using a range of keywords from inception to October 2017. Only peer-reviewed, population-based studies of oral health outcomes conducted among non-institutionalised participants and using mixed methods were considered eligible for inclusion. RESULTS: Only nine studies met the inclusion criteria and were included in the review. The most frequent oral health outcome investigated was caries experience. However, most studies lacked a theoretical rationale or framework for using mixed methods, or supporting the use of qualitative data. Concurrent triangulation with a convergent design was the most commonly used mixed methods typology for integrating quantitative and qualitative data. The tools used to collect quantitative and qualitative data were mostly limited to surveys and interviews. CONCLUSION: With growing complexity recognised in the determinants of oral disease, future studies addressing population oral health outcomes are likely to benefit from the use of mixed methods. Explicit consideration of theoretical framework and methodology will strengthen those investigations.

Calibration of dentists for Caries Management by Risk Assessment Research in a Practice Based Research Network - CAMBRA PBRN.

BACKGROUND: To prove that Caries Management by Risk Assessment (CAMBRA) can be successfully implemented in dental practices outside of the university setting, dentists in the San Francisco Bay Area (CA) were approached to participate in a Practice Based Research Network (PBRN) study. The overall goal of the CAMBRA-PBRN study was to recruit 30 dentists to perform a two-year study involving approximately 900 patients. Goal of the calibration study was to standardize and calibrate dentists potentially participating in the CAMBRA-PBRN study. METHODS: To minimize inter-examiner variability in data collection, including classification of carious lesions and recording of existing restorations, participating dentists were trained and calibrated in accurate DMFS (decayed, missing, filled surfaces) charting. Dentists were also trained and calibrated to diagnose and differentiate between sound surfaces and non-cavitated caries lesions (International Caries Detection and Assessment - ICDAS scores 1 and 2) for posterior occlusal surfaces. Thirty dentists were calibrated to a single gold standard examiner (BJ) during 6 calibration sessions, between 2011 and 2014. Kappa statistics were used to determine inter-examiner reliability on 13 or more patients, aged 12-63 (average age 38 ± 15 years), per examiner during each session, resulting in 94 patient encounters over the course of all 6 sessions. To participate in the main study, examiners needed to achieve a minimum required kappa of 0.75. During the calibration process, examiners scored between 1036 and 2220 tooth surfaces. RESULTS: The kappa values (unweighted kappa) of the participating dentists compared to the gold standard examiner ranged from 0.75 to 0.90, with an average kappa of 0.84 ± 0.03. 90% of the examiners achieved overall kappa values above 0.8. However, separate reliability for assessment of non-cavitated lesions, as in other studies, was lower (0.55 ± 0.15). Multiple subcategories were evaluated. All dentists reached sufficient reliability values to proceed into the study; nevertheless, one dentist discontinued with the study due to scheduling conflicts. CONCLUSIONS: The high inter-examiner reliability results have shown that dentists who work in primarily non-research based practices can be effectively standardized and calibrated in data collection, based on specific guidelines created to anticipate potential research study scenarios.

A proposal for using contralateral teeth to provide well-balanced experimental groups for endodontic studies.

AIM: To develop a suitable protocol for screening extracted teeth so as to create anatomically well-balanced experimental groups for endodontic studies. METHODOLOGY: Sixty pairs (120 teeth) of contralateral premolars (CLPs) were collected. The evaluation of samples for anatomical features was performed in the following ways. First, the 120 teeth were divided into right and left sides (N = 60, each side), and the teeth of each side were screened individually according to regular inclusion criteria (parameters included mature apical foramen, canal type, canal curvature and tooth length). The similarity of the specimens was then evaluated. The second screening process evaluated the 60 pairs of CLPs using the same criteria. Finally, CBCT was used to establish a strict screening protocol to create well-balanced groups of CLPs. RESULTS: In the first screening process, 80% (24/30) of the left and 61% (19/31) of the right side were selected out of teeth with mature foramina; but the included teeth had asymmetrical canal curvatures. In the second screening process, 28 pairs were selected after the exclusion of those with an immature foramen in one pair. Seventeen pairs in which the tooth length and canal curvature were symmetrical were selected from the 28 CLPs. In the third screening, only 21% (6/28) of CLPs passed the rigorous screening procedure and were identical for creating balanced experimental groups. CONCLUSIONS: Relatively, few pairs of contralateral teeth had anatomical symmetry. For endodontic studies, a strict and detailed scientific screening protocol is necessary to achieve well-balanced experimental groups.

Analysis of Small RNAs in Streptococcus mutans under Acid Stress-A New Insight for Caries Research.

Streptococcus mutans (S. mutans) is the major clinical pathogen responsible for dental caries. Its acid tolerance has been identified as a significant virulence factor for its survival and cariogenicity in acidic conditions. Small RNAs (sRNAs) are recognized as key regulators of virulence and stress adaptation. Here, we constructed three libraries of sRNAs with small size exposed to acidic conditions for the first time, followed by verification using qRT-PCR. The levels of two sRNAs and target genes predicted to be bioinformatically related to acid tolerance were further evaluated under different acid stress conditions (pH 7.5, 6.5, 5.5, and 4.5) at three time points (0.5, 1, and 2 h). Meanwhile, bacterial growth characteristics and vitality were assessed. We obtained 1879 sRNAs with read counts of at least 100. One hundred and ten sRNAs were perfectly mapped to reported msRNAs in S. mutans. Ten out of 18 sRNAs were validated by qRT-PCR. The survival of bacteria declined as the acid was increased from pH 7.5 to 4.5 at each time point. The bacteria can proliferate under each pH except pH 4.5 with time. The levels of sRNAs gradually decreased from pH 7.5 to 5.5, and slightly increased in pH 4.5; however, the expression levels of target mRNAs were up-regulated in acidic conditions than in pH 7.5. These results indicate that some sRNAs are specially induced at acid stress conditions, involving acid adaptation, and provide a new insight into exploring the complex acid tolerance for S. mutans.

Connecting and Collaborating: Developing National Dental PBRN Study Concepts Through POD Engagement.

PURPOSE: This article illustrates the process by which the Southwest Region of the National Dental Practice-Based Research Network (www.NationalDentalPBRN.org) fosters collaboration among practitioners and researchers in study concept development through protocol development groups (PODs). The Southwest Region begins this process by engaging PODs, which comprise dentists, hygienists, and/or academic faculty who share research interests related to improving dental care. METHOD: The PODs use the Tuckman four-stage model of group development (forming, storming, norming, and performing) to develop study concepts. This well-structured model encourages engagement among group members and enables quality discussion through organized sessions. This model provides milestones for the group's progression and for the members' interactions. The Southwest Region Directors play a crucial role in guiding and directing the development of PODs by aligning the members' research interests with the goals of the National Network. RESULTS: POD engagement using Tuckman's stages has been successful in developing study concepts for submission to the National Network. Between 2012 and 2014, the Southwest Region has developed 14 PODs from 275 research ideas. Five of these study concepts have been submitted to the National Network for approval, including the Novel Tobacco Products POD, which showcases the applicability of Tuckman's model. CONCLUSION: Overall, the POD concept is a collaborative effort that brings together practitioners and academicians through shared research interests and capitalizes on participants' expertise and experiences. The Southwest Region will continue to develop PODs to foster new ideas for future studies in the Network.

Focus group methods in dental research.

INTRODUCTION: Focus group methods have been increasingly used in dental research. However, although focus group methods appear quite simple and easy to carry out, there are a number of complexities that need to be considered. METHOD: The present integrative review was carried out to assess the usability of focus group methods for dental research. RESULTS: Three key themes were identified from the qualitative review: the complexity of the method; benefits of focus group research for dentistry; and, the nature of the quality controls employed. CONCLUSION: A key strength of using focus groups is that they can enhance qualitative and quantitative methodologies by helping to clarify, extend, qualify, or challenge what has been found.

Comparison of intervention effects in split-mouth and parallel-arm randomized controlled trials: a meta-epidemiological study.

BACKGROUND: Split-mouth randomized controlled trials (RCTs) are popular in oral health research. Meta-analyses frequently include trials of both split-mouth and parallel-arm designs to derive combined intervention effects. However, carry-over effects may induce bias in split- mouth RCTs. We aimed to assess whether intervention effect estimates differ between split- mouth and parallel-arm RCTs investigating the same questions. METHODS: We performed a meta-epidemiological study. We systematically reviewed meta- analyses including both split-mouth and parallel-arm RCTs with binary or continuous outcomes published up to February 2013. Two independent authors selected studies and extracted data. We used a two-step approach to quantify the differences between split-mouth and parallel-arm RCTs: for each meta-analysis. First, we derived ratios of odds ratios (ROR) for dichotomous data and differences in standardized mean differences (∆SMD) for continuous data; second, we pooled RORs or ∆SMDs across meta-analyses by random-effects meta-analysis models. RESULTS: We selected 18 systematic reviews, for 15 meta-analyses with binary outcomes (28 split-mouth and 28 parallel-arm RCTs) and 19 meta-analyses with continuous outcomes (45 split-mouth and 48 parallel-arm RCTs). [corrected]. Effect estimates did not differ between split-mouth and parallel-arm RCTs (mean ROR, 0.96, 95% confidence interval 0.52-1.80; mean ∆SMD, 0.08, -0.14-0.30). CONCLUSIONS: Our study did not provide sufficient evidence for a difference in intervention effect estimates derived from split-mouth and parallel-arm RCTs. Authors should consider including split-mouth RCTs in their meta-analyses with suitable and appropriate analysis.

Dental research related to COVID-19 in Brazil: research presented at the 38th SBPqO Meeting.

The aim of this study was to identify and describe the characteristics of coronavirus (COVID-19)-disease related dental research in Brazil presented at the 38th Annual Meeting of the Brazilian Division of the International Association for Dental Research (SBPqO). A search was carried out in the proceedings of the meeting to retrieve all abstracts. Those containing the term "COVID-19" in titles, abstracts, or keywords, and/or those of which the scope approached a COVID-19-related topic were included. The variables extracted from abstracts were: presenter category, field of study, design, data collection method, population, affiliation, and authors' gender. Descriptive and inferential statistics were used, with a significance level of α = 0.05. The search retrieved 185 abstracts, 5 did not meet study eligibility criteria and were excluded. COVID-19-related research was presented by either aspiring/associate members (67.8%) or beginner members (32.2%). Data collection methods were predominantly digitally mediated (65%), followed by secondary data use (25%), and in-person data collection (7.2%). Irrespective of the role of authorship, there were a ratio of two female authors to each male. Among the last authors, the ratio was three females to each male. Female lead authors more frequently came from the Southeast region (71.8%; p = 0.470). There was an association between presenter category and study design (p = 0.012), clinical and epidemiological studies were more concentrated among experienced presenters. In conclusion, female dental researchers affiliated to southeastern institutions approached the topic of pandemic more frequently than male colleagues. The use of digital technology for data collection may have long-lasting impacts on the teaching and publication of dental research.

Development of a quality-assessment tool for experimental bruxism studies: reliability and validity.

AIMS: To combine empirical evidence and expert opinion in a formal consensus method in order to develop a quality-assessment tool for experimental bruxism studies in systematic reviews. METHODS: Tool development comprised five steps: (1) preliminary decisions, (2) item generation, (3) face-validity assessment, (4) reliability and discriminitive validity assessment, and (5) instrument refinement. The kappa value and phi-coefficient were calculated to assess inter-observer reliability and discriminative ability, respectively. RESULTS: Following preliminary decisions and a literature review, a list of 52 items to be considered for inclusion in the tool was compiled. Eleven experts were invited to join a Delphi panel and 10 accepted. Four Delphi rounds reduced the preliminary tool-Quality-Assessment Tool for Experimental Bruxism Studies (Qu-ATEBS)- to 8 items: study aim, study sample, control condition or group, study design, experimental bruxism task, statistics, interpretation of results, and conflict of interest statement. Consensus among the Delphi panelists yielded good face validity. Inter-observer reliability was acceptable (k = 0.77). Discriminative validity was excellent (phi coefficient 1.0; P < .01). During refinement, 1 item (no. 8) was removed. CONCLUSION: Qu-ATEBS, the seven-item evidence-based quality assessment tool developed here for use in systematic reviews of experimental bruxism studies, exhibits face validity, excellent discriminative validity, and acceptable inter-observer reliability. Development of quality assessment tools for many other topics in the orofacial pain literature is needed and may follow the described procedure.

Rodent model in caries research.

The rodent model of dental caries has made fundamental contributions to the understanding of the etiology, pathogenesis, and prevention of this disease. In conducting animal-based investigations, important details considered essential for successful outcome are occasionally overlooked. Adequate number of animals of appropriate age should always be included to ensure sufficient statistical power to draw valid conclusions. Attention should be paid to litter source as it is clear that litter origin may have a profound effect on the outcome. Inclusion of additive in diet may also affect eating pattern. A range of special techniques are available which can expand the role of animals in exploring the pathogenesis of dental caries. The arrival of genetically altered microorganisms along with availability of knock-out rodents offers exciting challenges to further explore the pathogenesis of this still too common disease.

Journal-based learning, a new learning experience building on PBL at HKU.

OBJECTIVE: To evaluate the effectiveness of a new journal-based learning (JBL) programme designed to equip students with skills necessary to understand dental research publications, thereby preparing them for continuing professional development. MATERIALS AND METHODS: A baseline evaluation of knowledge relating to key research terms was conducted on 52 final-year BDS students. 11 weekly seminars were conducted from 8 clinical disciplines driven by a reading list of 2-5 journal articles along with a series of 'guidance' questions relating to research terms and content knowledge aspects of each paper to focus their reading and learning. Seminars were facilitated by discipline experts with supporting notes. An exit test based on research process and terminologies for the programme was conducted with 4 repeated questions from the baseline assessment. A systematic marking scheme was used and the results analysed. A focus group was run to collect feedback regarding students' views and experiences on the JBL experience. FINDINGS: Students showed significant improvements over the baseline score. The mean score rose from 3.5 to 11.5 in the repeated questions (P < 0.001). The focus group revealed that students had learnt new information about journal classification, evidence level determination, new research terms and the structure of research papers. From the first 4 years of PBL, students recognized the importance of learning from research papers since year 1. However, JBL gave them a deeper understanding of research and the development of critical appraisal skills. IMPLICATIONS: JBL provided final-year students the opportunity to learn significantly more about dental research, terminologies, paper structure, critical analysis and content knowledge through active-learning small group seminars.

A critical discussion of the benefits of e-health in population-level dental research.

Population-level research is an essential area of health with the potential to affect quality of life and the broader economy. There are excellent epidemiological studies that have improved health services, but traditional research requires a considerable investment. Although electronic technology has changed the practice of many industries with improved efficiency, its application to health is relatively new. Termed 'e-health', this emerging area has been defined by the World Health Organization as the use of information technology to support many aspects of health such as in administration and scientific information. However, not all professionals are convinced of its use. This paper presents a novel application of this emerging area to describe the benefit in data collation and research to support one of the most pressing issues in public health: oral health and policy. Using the Chronic Disease Dental Scheme as an example, a critical discussion of its benefit to population-level research is presented. The Chronic Disease Dental Scheme method of electronic administration has been shown to enhance research and to complement existing progress in health data linkage. e-Health is an invaluable tool for population-level dental research.

Methodological challenges in the study of dental occlusion.

This narrative review describes the methodological challenges in the study of dental occlusion. The reigning confusion about the scope of this topic is discussed, and a conceptual framework for understanding dental occlusion research is suggested. The characteristics of clinical studies used in the study of dental occlusion are presented within this proposed framework consisting of a triad comprising the relative positions of the teeth-mandible-maxilla, the oral functions and oral appearance. Challenges in the preparation for a clinical study of dental occlusion are reviewed, which include a discourse on the objectives of a clinical study and appropriateness of different study designs. Guidelines are provided for the conduct of studies with a central focus on dental occlusion and diagnostic tests, prognosis, therapy and aetiology, respectively. Summarising chapters present methodological challenges in designing a clinical study of dental occlusion and threats to the proper conduct of a clinical study.

Multidisciplinary research agenda for novel antimicrobial agents for caries prevention and treatment.

Antimicrobial methods to augment fluoride-mediated caries inhibition are necessary. Several methods are described here, but none was considered likely to be as effective as fluoride usage. None had been tested in effective models to demonstrate their ability to act either additively or synergistically with fluoride-containing toothpastes. Dental caries is a biofilm-mediated disease: The composition of the biofilm associated with caries initiation and progression is diverse. Caries-associated taxa - including mutans streptococci, lactobacilli, bifidobacteria, and yeasts - may be useful surrogate markers for in vivo investigations. In vitro testing should progress from single-species planktonic cells to multi-species biofilms prior to essential testing in randomized control trials (RCTs). Modern high-throughput sequencing techniques need to be applied to the study of bacterial acquisition from birth and of the composition of the biofilm associated with the formation of white-spot lesions. The determination of the functions of the biofilm and the phenotype of the bacterial components may be determined by RNA-seq techniques, since they must be conserved between caries lesions and will include the ability to produce acids and survive and proliferate in acidic conditions. The application of such methods will significantly improve our understanding of the etiology and progression of dental caries.

Dental hygienists as adult learners and educators to improve access to care.

OBJECTIVE: The purpose of the qualitative study was to understand dental hygienists as adult learners and educators in their quest to improve access to care. The intent of this article is to share the results from open and focused coding procedures and the participants' rich stories from which the analysis was constructed. METHODS: A grounded theory approach to data collection and analysis was used. Data were collected from eight practitioners in three US states who met the inclusion criteria, using semi-structured interviews. Traditional grounded theory procedures with a constructivist emphasis on lived experiences of the participants and situational analysis were used to analyse the data. RESULTS: The process of learning was experienced in three categories: Awareness, Adaptation and Relationships. Awareness was the process of learning participants experienced as developing consciousness of self, status quo, power and injustice of systems. Adaptation was constructed from experiences of specializing and creating to adjust to the new environments and prepare future practitioners. Relationships were developed to feel connected and collaborate to build support and gain respect to improve access to care. Dental hygienists as educators revealed one category: Improvement. Improvement was the process of educating others to enhance awareness, oral health and the dental hygiene profession. CONCLUSIONS: Dental hygienists were adult learners by using their experiences in the context of their struggle to improve health inequities. A strong educator role was necessary to make improvements in the oral health delivery system.

Potential systematic error in laboratory experiments on microbial leakage through filled root canals: review of published articles.

AIM: To systematically evaluate whether published studies on microbial leakage through filled root canals in human teeth embedded in a two-chamber system were properly controlled. Specifically, the control for the assumption that leakage should occur through the root canal rather than other routes was investigated. METHODOLOGY: A systematic search was conducted using Medline, Biosis, Cochrane, Embase, and Web of Science databases. In addition, the reference lists of review articles pertaining to the topic were searched. No language restriction was applied. Two independent reviewers screened titles and abstracts. All articles deemed appropriate by either reviewer were included in the full-text evaluation. In case of disagreement, a referee arbitrated between the reviewers. RESULTS: With 93.8% agreement prior to discussion and arbitration, 67 articles were included. On average, the size of the negative control group was 30% (mean) of the n in the experimental groups (minimum=0.0%, maximum=100%, SD=27%). The majority of studies (57 of 67) used inadequate negative controls. The whole root was covered with the sealing material in these specimens, whilst the root tip was left uncovered in the experimental groups. Consequently, leakage between outer root surface and sealing material was not controlled for. The authors of the remaining 10 communications did not state clearly how negative control assessments were performed. CONCLUSIONS: Experimental investigations should be performed to assess the routes of microbial leakage in two-chamber models.

Potential systematic error in laboratory experiments on microbial leakage through filled root canals: an experimental study.

AIM: To assess the routes of bacterial leakage in a commonly used two-chamber model designed to evaluate root fillings. METHODOLOGY: Fifty-one intact human mandibular premolars with fully developed roots were used. They were left completely intact (n=23), or were accessed, instrumented and either left open (n=5) or root filled with gutta-percha and AH Plus (n=23). All teeth were sealed between two chambers using sticky wax. The apical root aspects were left uncovered. The upper chamber was seeded with Enterococcus faecalis. An enterococci-selective broth was used in the lower chamber. Leakage was assessed for 120 days and compared using survival statistics (α<0.05). Subsequently, roots were trans-sected, stained using a 'live' DNA stain (Syto59) and inspected using confocal laser scanning microscopy. An E. faecalis-specific RNA probe was used for fluorescence in situ hybridization (FISH). RESULTS: Leakage started to occur from day 56, with further occurrence essentially identical between root filled teeth and intact counterparts (P=0.71). All the trans-sections showed fluorescence related to Syto59 between the cementum layer and the sticky wax. Fluorescence was also observed between the root filling and the tubular dentine, whilst it was absent at the interface between root filling and sclerotic dentine. Secondary dentinal tubules, i.e. lateral branches connecting the main counterparts, contained fluorescent material. FISH revealed that Syto59 exclusively stained E. faecalis. CONCLUSIONS: The current experimental method proved to be unsuitable to compare root fillings. Histology revealed interesting observations regarding the relationship of dentine structure and bacterial leakage, which warrant further investigation.

Pooling of dentin microtensile bond strength data improves clinical correlation.

PURPOSE: To evaluate whether the correlation between in vitro bond strength data and estimated clinical retention rates of cervical restorations after two years depends on pooled data obtained from multicenter studies or single-test data. MATERIALS AND METHODS: Pooled mean data for six dentin adhesive systems (Adper Prompt L-Pop, Clearfil SE, OptiBond FL, Prime & Bond NT, Single Bond, and Scotchbond Multipurpose) and four laboratory methods (macroshear, microshear, macrotensile and microtensile bond strength test) (Scherrer et al, 2010) were correlated to estimated pooled two-year retention rates of Class V restorations using the same adhesive systems. For bond strength data from a single test institute, the literature search in SCOPUS revealed one study that tested all six adhesive systems (microtensile) and two that tested five of the six systems (microtensile, macroshear). The correlation was determined with a database designed to perform a meta-analysis on the clinical performance of cervical restorations (Heintze et al, 2010). The clinical data were pooled and adjusted in a linear mixed model, taking the study effect, dentin preparation, type of isolation and bevelling of enamel into account. A regression analysis was carried out to evaluate the correlation between clinical and laboratory findings. RESULTS: The results of the regression analysis for the pooled data revealed that only the macrotensile (adjusted R2 = 0.86) and microtensile tests (adjusted R2 = 0.64), but not the shear and the microshear tests, correlated well with the clinical findings. As regards the data from a single-test institute, the correlation was not statistically significant. CONCLUSION: Macrotensile and microtensile bond strength tests showed an adequate correlation with the retention rate of cervical restorations after two years. Bond strength tests should be carried out by different operators and/or research institutes to determine the reliability and technique sensitivity of the material under investigation.