Lessons learned during the conduct of clinical studies in the dental PBRN

Effectively addressing challenges of conducting research in nonacademic settings is crucial to its success. A dental practice-based research network called The Dental Practice-Based Research Network (DPBRN) is comprised of practitioner- investigators in two health maintenance organizations, several universities, many U.S. states, and three Scandinavian countries. Our objective in this article is to describe lessons learned from conducting studies in this research context; the studies are conducted by clinicians in community settings who may be doing their first research study. To date, twenty-one studies have been completed or are in implementation. These include a broad range of topic areas, enrollment sizes, and study designs. A total of 1,126 practitioner-investigators have participated in at least one study. After excluding one study because it involved electronic records queries only, these studies included more than 70,000 patient/participant units. Because the DPBRN is committed to being both practitioner- and patient-driven, all studies must be approved by its Executive Committee and a formal study section of academic clinical scientists. As a result of interacting with a diverse range of institutional and regulatory entities, funding agencies, practitioners, clinic staff, patients, academic scientists, and geographic areas, twenty-three key lessons have been learned. Patients' acceptance of these studies has been very high, judging from high participation rates and their completion of data forms. Early studies substantially informed later studies with regard to study design, practicality, forms design, informed consent process, and training and monitoring methods. Although time-intensive and complex, these solutions improved acceptability of practice-based research to patients, practitioners, and university researchers.

Methods used by Dental Practice-based Research Network (DPBRN) dentists to diagnose dental caries

OBJECTIVES

To (1) identify the methods that dentists in The Dental Practice-Based Research Network (DPBRN) use to diagnose dental caries; (2) quantify their frequency of use and (3) test the hypothesis that certain dentist and dental practice characteristics are significantly associated with their use.

METHODS

A questionnaire about methods used for caries diagnosis was sent to DPBRN dentists who reported doing some restorative dentistry; 522 dentists participated. Questions included the use of dental radiographs, the dental explorer, laser fluorescence, air-drying and fiber-optic devices and magnification as used when diagnosing primary, secondary/recurrent or non-specific caries lesions. Variations on the frequency of their use were tested using multivariate analysis and Bonferroni tests.

RESULTS

Overall, the dental explorer was the instrument most commonly used to detect primary occlusal caries and caries at the margins of existing restorations. In contrast, laser fluorescence was rarely used to help diagnose occlusal primary caries. For proximal caries, radiographs were used to help diagnose 75%–100% of lesions by 96% of the DPBRN dentists. Dentists who use radiographs most often to assess proximal surfaces of posterior teeth were significantly more likely to also report providing a higher percentage of patients with individualized caries prevention (p=.040) and seeing a higher percentage of pediatric patients (p=.001).

CONCLUSION

The use of specific diagnostic methods varied substantially. The dental explorer and radiographs are still the most commonly used diagnostic methods..

Oral health-related quality of life and life-space mobility in community-dwelling older adults

OBJECTIVES

To quantify the associations between measures of oral health-related quality of life (OHRQoL) and life-space mobility (LSM) in community-dwelling older adults.

DESIGN

Cross-sectional study using a 54-item OHRQoL questionnaire.

SETTING

Five counties in central Alabama: Jefferson and Tuscaloosa (urban), and Bibb, Hale, and Pickens (rural).

PARTICIPANTS

The 288 dental study volunteers were recruited from participants in the University of Alabama at Birmingham Study of Aging, a longitudinal study of mobility in community-dwelling adults aged 65 and older.

MEASUREMENTS

Participants completed an in-home interview about their OHRQoL and LSM. Life-space was assessed by asking questions about where and how often participants got to areas ranging from the home to beyond town and the degree of independence in getting there. Unadjusted and adjusted regression models were used to quantify associations between OHRQoL and LSM. Other factors examined were age, race, sex, income, education, residence, transportation difficulty, marital status, depressive symptoms, and comorbidity.

RESULTS

Unadjusted and adjusted analyses suggested significant associations between OHRQoL and LSM in oral functional limitation, oral pain and discomfort, oral disadvantage, and self-rated oral health.

CONCLUSION

OHRQoL decrements that participants reported were associated with less LSM, suggesting that perceptions of oral well-being have a significant effect on mobility and the social participation of older adults.

Cognitive mapping tobacco control advice for dentistry: a dental PBRN study

OBJECTIVE

To identify facilitative strategies that could be used in developing a tobacco cessation program for community dental practices.

METHODS

Nominal group technique (NGT) meetings and a card-sort task were used to obtain formative data. A cognitive mapping approach involving multidimensional scaling and hierarchical cluster analysis was used for data analysis.

RESULTS

Three NGT meetings conducted with 23 dental professionals yielded 27 nonredundant facilitative strategies. A 2-dimensional 4-cluster cognitive map provided an organizational framework for understanding these strategies.

CONCLUSION

Views of the target population solicited in a structured format provided clear direction for designing a tobacco cessation intervention.

Risk factors for osteonecrosis of the jaws: a case-control study from the CONDOR dental PBRN

Case reports and cohort studies have linked bisphosphonate therapy and osteonecrosis of the jaws (ONJ), but neither causality nor specific risks for lesion development have been clearly established. We conducted a 1:3 case-control study with three dental Practice-based Research Networks, using dentist questionnaires and patient interviews for collection of data on bisphosphonate therapy, demographics, co-morbidities, and dental and medical treatments. Multivariable logistic regression analyses tested associations between bisphosphonate use and other risk factors with ONJ. We enrolled 191 ONJ cases and 573 controls in 119 dental practices. Bisphosphonate use was strongly associated with ONJ (odds ratios [OR] 299.5 {95%CI 70.0-1282.7} for intravenous [IV] use and OR = 12.2 {4.3-35.0} for oral use). Risk markers included local suppuration (OR = 7.8 {1.8-34.1}), dental extraction (OR = 7.6 {2.4-24.7}), and radiation therapy (OR = 24.1 {4.9-118.4}). When cancer patients (n = 143) were excluded, bisphosphonate use (OR = 7.2 {2.1-24.7}), suppuration (OR = 11.9 {2.0-69.5}), and extractions (OR = 6.6 {1.6-26.6}) remained associated with ONJ. Higher risk of ONJ began within 2 years of bisphosphonate initiation and increased four-fold after 2 years. Both IV and oral bisphosphonate use were strongly associated with ONJ. Duration of treatment > 2 years; suppuration and dental extractions were independent risk factors for ONJ.

Impact of denture usage patterns on dietary quality and food avoidance among older adults

This study categorizes older adults living in rural areas by denture status, assesses the frequency of wearing dentures during meals, and determines whether denture status or use is associated with dietary quality or the number of foods avoided. A multi-ethnic population-based sample of adults ≥60 years (N = 635) in the rural United States was interviewed. Survey included denture use, removing dentures before eating, and foods avoided due to oral health problems. Dietary intakes were converted into Healthy Eating Index-2005 scores. Sixty percent wore removable dentures of some type; 55% never, 27% sometimes, and 18% always removed dentures when eating. More frequent removal was associated with lower dietary quality and more foods avoided. Those with severe tooth loss had the lowest dietary quality and avoided the most foods. Many rural older adults wear dentures. Learning how they adapt to denture use will offer insight into their nutritional self-management and help explain differences in dietary quality.

Four "lessons learned" while implementing a multi-site caries prevention trial

As the number of dental-related randomized clinical trials (RCTs) increases, there is a need for literature to help investigators inexperienced in conducting RCTs design and implement studies. This commentary describes four "lessons learned" or considerations important in the planning and initial implementation of RCTs in dentistry that, to our knowledge, have not been discussed in the general dental literature describing trial techniques. These considerations are a) preparing or securing a thorough systematic review; b) developing a comprehensive set of study documents; c) designing and testing multiple recruitment strategies; and d) employing a run-in period prior to enrollment. Attention to these considerations in the planning phases of a dental RCT can help ensure that the trial is clinically relevant while also maximizing the likelihood that its implementation will be successful.

Methods dentists use to diagnose primary caries lesions prior to restorative treatment: findings from The Dental PBRN

OBJECTIVE

To (1) quantify the diagnostic techniques used by Dental Practice-Based Research Network (DPBRN) dentists before they decide to treat primary caries lesions surgically and (2) examine whether certain dentist, practice, and patient characteristics are associated with their use.

METHODS

A total of 228 DPBRN dentists recorded information on 5676 consecutive restorations inserted due to primary caries lesions on 3751 patients. Practitioner-investigators placed a mean of 24.9 (SD=12.4) restorations. Lesions were categorised as posterior proximal, anterior proximal, posterior occlusal, posterior smooth, or anterior smooth. Techniques used to diagnose the lesion were categorised as clinical assessment, radiographs, and/or optical. Statistical analysis utilised generalised mixed-model ANOVA to account for the hierarchical structure of the data.

RESULTS

By lesion category, the diagnostic technique combinations used most frequently were clinical assessment plus radiographs for posterior proximal (47%), clinical assessment for anterior proximal (51%), clinical assessment for posterior occlusal (46%), clinical assessment for posterior smooth (77%), and clinical assessment for anterior smooth (80%). Diagnostic technique was significantly associated with lesion category after adjusting for clustering in dentists (p<0.0001).

CONCLUSION

These results - obtained during actual clinical procedures rather than from questionnaire-based hypothetical scenarios - quantified the diagnostic techniques most commonly used during the actual delivery of routine restorative care. Diagnostic technique varied by lesion category and with certain practice and patient characteristics.

Rubber dam use during routine operative dentistry procedures: findings from the Dental PBRN

Rubber dam use during operative dentistry procedures has been quantified based on questionnaires completed by dentists. However, based on the knowledge of the authors of the current study, there are no reports based on use during actual clinical procedures other than in dental materials studies and none based on routine care. The objectives of the current study were to: 1) quantify how commonly the rubber dam is used during operative dentistry procedures; 2) test the hypothesis that certain dentist, restoration and patient-level factors are associated with its use. A total of 229 dentist practitioner-investigators in The Dental Practice-Based Research Network (DPBRN) participated. DPBRN comprises five regions of the USA: Alabama/Mississippi, Florida/Georgia, Minnesota, Permanente Dental Associates and Scandinavia. Practitioner-investigators collected data on 9,890 consecutive restorations done in previously unrestored tooth surfaces from 5,810 patients. Most dentists (63%) did not use a rubber dam for any restoration in this study. A rubber dam was used for only 12% of restorations, 83% of which were used in one DPBRN region. With regions accounted for, no other dentist characteristics were significant. A multi-level multiple logistic regression of rubber dam use was done with restoration and patient-level variables modeled simultaneously. In this multi-variable context, these restoration-level characteristics were statistically significant: tooth-arch type, restoration classification and reason for placing the restoration. These patient-level characteristics were statistically significant: ethnicity, dental insurance and age. These results, obtained from actual clinical procedures rather than questionnaires, document a low prevalence of usage of the rubber dam during operative dentistry procedures. Usage varied with certain dentist, restoration and patient-level characteristics.

Change in stated clinical practice associated with participation in the Dental Practice-Based Research Network

Clinical researchers have attempted many methods to translate scientific evidence into routine clinical practice, with varying success. Practice-based research networks (PBRNs) provide an important, practitioner-friendly venue to test these methods. Dentist practitioner-investigators from the Dental Practice-Based Research Network (DPBRN) completed a detailed questionnaire about how they diagnose and treat dental caries. Next, they received a customized report that compared their answers to those from all other practitioner-investigators. Then, 126 of them attended the DPBRN's first network-wide meeting of practitioner-investigators from all five of its regions. During that meeting, certain questions were repeated and new ones were asked about the dentist's intention to change the way that he or she diagnosed or treated dental caries. Less than one-third of practitioner-investigators intended to change how they diagnosed or treated caries as a result of receiving the customized report. However, as a result of the meeting, the majority of these same practitioner-investigators stated an intention to change toward a more conservative, less surgically invasive approach. These findings are consistent with the idea that a highly interactive meeting with fellow practitioner-investigators may be an effective means to translate scientific findings into clinical practice. Practitioner-investigators are open to changing how they treat patients as a result of engaging fellow practitioner-investigators in the scientific process.

Design of the xylitol for adult caries trial (X-ACT)

Background

Dental caries incidence in adults is similar to that in children and adolescents, but few caries preventive agents have been evaluated for effectiveness in adults populations. In addition, dentists direct fewer preventive services to their adult patients. Xylitol, an over-the-counter sweetener, has shown some potential as a caries preventive agent, but the evidence for its effectiveness is not yet conclusive and is based largely on studies in child populations.

Methods/Design

X-ACT is a three-year, multi-center, placebo controlled, double-blind, randomized clinical trial that tests the effects of daily use of xylitol lozenges versus placebo lozenges on the prevention of adult caries. The trial has randomized 691 participants (ages 21-80) to the two arms. The primary outcome is the increment of cavitated lesions.

Discussion

This trial should help resolve the overall issue of the effectiveness of xylitol in preventing caries by contributing evidence with a low risk of bias. Just as importantly, the trial will provide much-needed information about the effectiveness of a promising caries prevention agent in adults. An effective xylitol-based caries prevention intervention would represent an easily disseminated method to extend caries prevention to individuals not receiving caries preventive treatment in the dental office.

Trial Registration

ClinicalTrials.Gov NCT00393055

Concordance between preoperative and postoperative assessments of primary caries lesion depth: results from the Dental PBRN

This study investigated the concordance between pre- and postoperative assessments of primary caries lesion depths by dentists from The Dental Practice-Based Research Network (DPBRN; www.DentalPBRN.org). A total of 229 DPBRN dentists collected data on 8,351 consecutive restorations inserted due to primary caries in 5,810 patients. Dentists estimated the preoperative depth of caries lesions based on the diagnostic methods they typically used. The preoperative depth was then compared to the postoperative depth, which dentists determined using actual clinical observation. Both estimated and observed depths were recorded as being in the outer half (E1) or inner half (E2) of enamel, or in the outer third (D1), middle third (D2) or inner third (D3) of dentin. Most restorations were placed to treat lesions that were preoperatively assessed as extending to the D1 (53%) and D2 (25%) depths. Of the restored caries lesions, 10% were preoperatively assessed as being limited to E2 depth and 3% to E1 depth. The majority of the restored enamel lesions were located on occlusal surfaces. Preoperative estimates of caries lesion depth were more concordant with postoperative depths when the lesion was at an advanced stage: 88% concordance at the D3 depth, compared to 54% concordance at the E1 depth. DPBRN dentists can discriminate caries lesions at different depths, but the accuracy of their depth assessments was higher for dentin than for enamel lesions. In general, DPBRN dentists were more likely to underestimate than overestimate the depth of caries lesions, and the extent of underestimation was greater for enamel than for dentin lesions.

Preferences for caries prevention agents in adult patients: findings from the dental practice-based research network

OBJECTIVES

To identify factors that are significantly associated with dentists' use of specific caries preventive agents in adult patients, and whether dentists who use one preventive agent are also more likely to use certain others.

METHODS

Data were collected from 564 practitioners in The Dental Practice-Based Research Network, a multi-region consortium of participating practices and dental organizations.

RESULTS

In-office topical fluoride was the method most frequently used. Regarding at-home preventive agents, there was little difference in preference between nonprescription fluoride, prescription fluoride, or chlorhexidine rinse. Dentists who most frequently used caries prevention were also those who regularly perform caries risk assessment and individualize caries prevention at the patient level. Higher percentages of patients with dental insurance were significantly associated with more use of in-office prevention modalities. Female dentists and dentists with more-recent training were more likely to recommend preventive agents that are applied by the patient. Dentists who reported more-conservative decisions in clinical treatment scenarios were also more likely to use caries preventive agents. Groups of dentist who shared a common preference for certain preventive agents were identified. One group used preventive agents selectively, whereas the other groups predominately used either in-office or at-home fluorides.

CONCLUSIONS

Caries prevention is commonly used with adult patients. However, these results suggest that only a subset of dentists base preventive treatments on caries risk at the individual patient level.

Association between dietary quality of rural older adults and self-reported food avoidance and food modification due to oral health problems

OBJECTIVES

To quantify the association between food avoidance and modification due to oral health problems, to examine the association between food practices and dietary quality, and to determine foods associated with these self-management behaviors.

DESIGN

Cross-sectional.

SETTING

Rural North Carolina.

PARTICIPANTS

Six hundred thirty-five community-dwelling adults aged 60 and older.

MEASUREMENTS

Demographic and food frequency data and oral health assessments were obtained during home visits. Avoidance (0, 1-2 foods, 3-14 foods) and modification (0-3 foods, 4-5 foods) due to oral health problems were assessed for foods representing oral health challenges. Food frequency data were converted into Healthy Eating Index-2005 (HEI-2005) scores. Linear regression models tested the significance of associations between HEI-2005 measures and food avoidance and modification.

RESULTS

Thirty-five percent of participants avoided three to 14 foods, and 28% modified four to five foods. After adjusting for age, sex, ethnicity, poverty, education, and tooth loss, total HEI-2005 score was lower (P<.001) for persons avoiding more foods and higher for persons modifying more foods (P<.001). Those avoiding three to 14 foods consumed more saturated fat and energy from solid fat and added sugar and less nonhydrogenated fat than those avoiding fewer than three foods. Those who modified four to five foods consumed less saturated fat and solid fat and added sugar but more total grains than those modifying fewer than four foods.

CONCLUSION

Food avoidance and modification due to oral health problems are associated with significant differences in dietary quality. Approaches to minimize food avoidance and promote food modification by persons having eating difficulties due to oral health conditions are needed.

Institutional review board and regulatory solutions in the dental PBRN

OBJECTIVES

Effectively addressing regulatory and human participant protection issues with Institutional Review Boards (IRBs, or ethics committees) and grants administration entities is an important component of conducting research in large collaborative networks. A dental practice-based research network called "DPBRN" (http://www.DPBRN.org) comprises dentists in two health maintenance organizations, several universities, seven US states, and three Scandinavian countries. Our objectives are to describe: a) the various human participants and regulatory requirements and solutions for each of DPBRN's five regions; b) their impact on study protocols and implementation; and c) lessons learned from this process.

METHODS

Following numerous discussions with IRB and grants administrative personnel for each region, some practitioner-investigators are attached to their respective IRBs and contracting entities via sub-contracts between their organizations and the network's administrative site. Others are attached via Individual Investigator Agreements and contractually obligated via Memoranda of Agreement.

RESULTS

IRBs approve general operations under one approval, but specific research projects via separate approvals. Various formal IRB and grants administrative agreements have been arranged to customize research to the network context. In some instances, this occurred after feedback from patients and practitioners that lengthy written consent forms impeded research and raised suspicion, instead of decreasing it.

CONCLUSIONS

Instead of viewing IRBs and institutional administrators as potentially adversarial, customized solutions can be identified by engaging them in collegial discussions that identify common ground within regulatory bounds. Although time-intensive and complex, these solutions improve acceptability of practice-based research to patients, practitioners, and university researchers.

Dentists' use of caries risk assessment in children: findings from the Dental Practice-Based Research Network

This study surveyed Dental Practice-Based Research Network (DPBRN) member dentists (from four regions in the U.S. and Scandinavia) who perform restorative dentistry in their practices. The survey asked a range of questions about caries risk assessment in patients aged 6 to 18. Among respondents, 73% of dentists reported performing caries risk assessment among these patients, while 14% assessed caries risk by using a special form. Regions in which most dentists were in a private practice model were the least likely to perform caries risk assessment, while regions where most dentists practiced in a large group practice model were the most likely to use a special form for caries risk assessment. Recent graduates from dental school were more likely to use a caries risk assessment compared to older graduates. Current oral hygiene, decreased salivary flow, and the presence of active caries were rated as the most important caries factors. Some differences by region were also evident for the risk factor ratings. These results suggest that not all community dentists assess caries risk. The results of this study also indicate considerable variability in dentists' views concerning the importance of specific caries risk factors in treatment planning and weak evidence that caries risk assessment is driving clinical practice when preventive treatment recommendations are being considered.

Pay for performance: will dentistry follow?

BACKGROUND

"Pay for performance" is an incentive system that has been gaining acceptance in medicine and is currently being considered for implementation in dentistry. However, it remains unclear whether pay for performance can effect significant and lasting changes in provider behavior and quality of care. Provider acceptance will likely increase if pay for performance programs reward true quality. Therefore, we adopted a quality-oriented approach in reviewing those factors which could influence whether it will be embraced by the dental profession.

DISCUSSION

The factors contributing to the adoption of value-based purchasing were categorized according to the Donabedian quality of care framework. We identified the dental insurance market, the dental profession position, the organization of dental practice, and the dental patient involvement as structural factors influencing the way dental care is practiced and paid for. After considering variations in dental care and the early stage of development for evidence-based dentistry, the scarcity of outcome indicators, lack of clinical markers, inconsistent use of diagnostic codes and scarcity of electronic dental records, we concluded that, for pay for performance programs to be successfully implemented in dentistry, the dental profession and health services researchers should: 1) expand the knowledge base; 2) increase considerably evidence-based clinical guidelines; and 3) create evidence-based performance measures tied to existing clinical practice guidelines.

SUMMARY

In this paper, we explored factors that would influence the adoption of value-based purchasing programs in dentistry. Although none of these factors were essential deterrents for the implementation of pay for performance programs in medicine, the aggregate seems to indicate that significant changes are needed before this type of program could be considered a realistic option in dentistry.

Outcomes of root canal treatment in Dental Practice-Based Research Network practices

This study sought to quantify the incidence of root canal treatment (RCT) failure and identify its predictors in root canals that were performed or referred by general dentistry practices in a practice-based research network (PBRN). This retrospective cohort study involved 174 endodontically treated teeth. Mean duration from initial therapy to follow-up was 8.6 years. Permanent restorations were ultimately placed in 89% of teeth, although 18% of teeth were ultimately extracted anyway. Receiving a permanent restoration was a significant predictor of treatment failure (in other words, patients who did not receive a permanent restoration were more likely to experience RCT failure), whether failure was determined clinically or radiographically. This study of PBRN practices suggests a higher failure rate compared with studies that utilized highly controlled environments or populations with high levels of dental insurance.

Use of caries-preventive agents in children: findings from the dental practice-based research network

PURPOSE

Scientific evidence supports the application of caries-preventive agents in children and adolescents, and this knowledge must be applied to the practice of dentistry. There are few multi-region data that allow for comparisons of practice patterns between types of dental practices and geographical regions. The objective of the present study was to characterise the use of specific caries-preventive agents for paediatric patients in a large multi-region sample of practising clinicians.

METHODS

The present study surveyed clinicians from the Dental Practice-based Research Network who perform restorative dentistry in their practices. The survey consisted of a questionnaire that presented a range of questions about caries risk assessment and the use of preventive techniques in children aged 6 to 18 years.

RESULTS

Dental sealants (69%) or in-office fluoride (82%) were the most commonly used caries-preventive agents of the caries preventive regimens. The recommendation of at-home caries-preventive agents ranged from 36% to 7%,with the most commonly used agent being non-prescription fluoride rinse. Clinicians who practised in a large group practice model and clinicians who come from the Scandinavian region use caries risk assessment more frequently compared to clinicians who come from regions that had, predominantly, clinicians in private practice. Whether or not clinicians used caries risk assessment with their paediatric patients was poorly correlated with the likelihood of actually using caries-preventive treatments on patients.

CONCLUSIONS

Although clinicians reported the use of some form of in-office caries-preventive agent, there was considerable variability across practices. These differences could represent a lack of consensus across practising clinicians about the benefits of caries-preventive agents, or a function of differing financial incentives, or patient pools with differing levels of overall caries risk.

Pay-for-performance in dentistry: what we know

Little is known about the effect of a pay-for-performance system (P4P) on primary medical care providers and even less is known about its potential impact in dentistry. Based on the growing acceptance of performance-based reimbursements in medicine and the dissemination of innovative technologies, structures, and processes of care from medical to dental services, it is likely that the dental profession will face performance-based payments in the not-too-distant future. In this paper, we present the current experience of P4P in primary medical care that has relevance to dentistry and discuss the dental performance-based programs to date. Taking into consideration these lessons, the structure of dental service delivery in the United States, and the paucity of evidence-based quality indicators in dentistry, we provide several guidelines for the design of P4P pilot programs for dental services. We conclude that large-scale implementation of P4P for dentistry may not be a realistic option before significant progress is achieved in quality of dental care indicators.

Impact of content-specific email reminders on provider participation in an online intervention: a dental PBRN study

Engaging busy healthcare providers in online continuing education interventions is challenging. In an Internet-delivered intervention for dental providers, we tested a series of email-delivered reminders - cues to action. The intervention included case-based education and downloadable practice tools designed to encourage providers to increase delivery of smoking cessation advice to patients. We compared the impact of email reminders focused on 1) general project announcements, 2) intervention related content (smoking cessation), and 3) unrelated content (oral cancer prevention focused content). We found that email reminders dramatically increased participation. The content of the message had little impact on the participation, but day of the week was important - messages sent at the end of the week had less impact, likely due to absence from clinic on the weekend. Email contact, such as day of week an email is sent and notice of new content post-ing, is critical to longitudinal engagement. Further research is needed to understand which messages and how frequently, will maximize participation.

How dentists diagnose and treat defective restorations: evidence from the dental practice-based research network

OBJECTIVES

To (1) identify and quantify the types of treatment that dentists use to manage defective dental restorations and (2) identify characteristics that are associated with these dentists' decisions to replace existing restorations. The Dental Practice-Based Research Network (DPBRN) consists of dentists in outpatient practices from five regions: AL/MS: Alabama/Mississippi; FL/GA: Florida/Georgia; MN: dentists employed by HealthPartners and private practitioners in Minnesota; PDA: Permanente Dental Associates in cooperation with Kaiser Permanente's Center for Health Research and SK: Denmark, Norway and Sweden.

METHODS

A questionnaire was sent to all DPBRN practitioner-investigators who reported doing some restorative dentistry (n = 901). Questions included clinical case scenarios that used text and clinical photographs of defective restorations. Dentists were asked what type of treatment, if any, they would use in each scenario. Treatment options ranged from no treatment to full replacement of the restoration with or without different preventive treatment options. The authors of the current study used logistic regression to analyze associations between the decision to intervene surgically (repair or replace) and the specific dentist, practice and patient characteristics.

RESULTS

A total of 65% of dentists would replace a composite restoration when the defective margin was located on dentin and 49% would repair it when the defective margin was located on enamel. Most (52%) dentists would not intervene surgically when the restoration in the scenario was amalgam. Dentists participating in a solo or small private practice (SPP) chose surgical intervention more often than dentists participating in large group practices (LGP) or in public health practices (PHP) (p < .0001). Dentists who do not routinely assess caries risk during treatment planning were more likely to intervene surgically and less likely to choose prevention treatment (p < .05). Dentists from the SK region chose the "no treatment" option more often than dentists in the other regions.

CONCLUSIONS

Dentists were more likely to intervene surgically when the restoration was an existing composite, compared to an amalgam restoration. Treatment options chosen by dentists varied significantly by specific clinical case scenario, whether the dentist routinely performs caries risk assessment, type of practice and DPBRN region.

Restorative treatment thresholds for interproximal primary caries based on radiographic images: findings from the Dental Practice-Based Research Network

This study sought to quantify the depths of proximal caries lesions that lead dentists in regular clinical practice to intervene restoratively, based on hypothetical scenarios that present radiographic images and patient background information, and to identify characteristics associated with restorative intervention in lesions that have penetrated only the enamel surface. This study surveyed dentists from the Dental Practice-Based Research Network (DPBRN) who had reported doing at least some restorative dentistry (n = 901). Dentists were asked to indicate the depth at which they would restore a lesion, based on a series of radiographic images depicting interproximal caries at increasing lesion depths in a mandibular premolar; in addition, the dentists were questioned regarding two caries risk scenarios: one involving a patient with low caries risk and another involving a patient at higher risk. Logistic regression was used to analyze associations between the decision to intervene restoratively and specific dentist, practice, and patient characteristics. Of the 901 DPBRN practitioner-investigators, 500 (56%) completed the survey. For a high caries risk patient, 66% of respondents indicated that they would restore a proximal enamel lesion, while 24% would do so once the lesion had reached into the outer third of the dentin. For a low caries risk patient, 39% of respondents reported that they would restore an enamel lesion, and 54% would do so once the lesion had reached into the outer third of the dentin. In multivariate analyses that accounted for dentist and practice characteristics, dentists in large group practices were less likely to intervene surgically for enamel caries, regardless of patient's caries risk.