Clinical acceptance of single-unit crowns and its association with impression and tissue displacement techniques: Findings from the National Dental Practice-Based Research Network.

STATEMENT OF PROBLEM: The definitive impression for a single-unit crown involves many material and technique factors that may affect the success of the crown. PURPOSE: The purpose of this prospective cohort study was to determine whether impression technique (tray selection), impression material, or tissue displacement technique are associated with the clinical acceptability of the crown (CAC). MATERIAL AND METHODS: Dentists in the National Dental Practice-Based Research Network documented details of the preparation, impression, and delivery of 3730 consecutive single-unit crowns. Mixed-effects logistic regression analyses were performed to evaluate associations between impression techniques and materials and the CAC and to assess associations between the presence of a subgingival margin with the displacement technique and the outcome variables CAC and number of impressions required. RESULTS: Of the 3730 crowns, 3589 (96.2%) were deemed clinically acceptable. A significant difference in the CAC was found with different impression techniques (P<.001) and different impression materials (P<.001). The percentage of the CAC for digital scans was 99.5%, 95.8% for dual-arch trays, 95.2% for quadrant trays, and 94.0% for complete-arch impression trays. Although no statistically significant difference was found in the CAC produced with dual-arch trays without both mesial and distal contacts, crowns fabricated under these conditions were less likely to achieve excellent occlusion. The percentage of the CAC for digital scans was 99.5%, 97.0% for polyether impressions, 95.5% for polyvinyl siloxane impressions, and 90.5% for other impression materials. Accounting for the location of the margin, the use of a dual-cord displacement technique was significantly associated with lower rates of requiring more than 1 impression (P=.015, odds ratio=1.43). CONCLUSIONS: Dual-arch trays produced clinically acceptable crowns; however, if the prepared tooth was unbounded, the occlusal fit was more likely to have been compromised. Digital scans produced a slightly higher rate of CAC than conventional impression materials. The use of a dual-cord technique was associated with a decreased need to remake impressions when the margins were subgingival.

Laboratory Technician Assessment of the Quality of Single-Unit Crown Preparations and Impressions as Predictors of the Clinical Acceptability of Crowns as Determined by the Treating Dentist: Findings from the National Dental Practice-Based Research Network.

PURPOSE: In-laboratory assessment by laboratory technicians may offer insight to increase clinical success of dental crowns, and research in this area is lacking. MATERIALS AND METHODS: Dentists in the National Dental Practice-Based Research Network enrolled patients in a study about single-unit crowns; laboratory technicians evaluated the quality of tooth preparations and impressions. The primary outcome for each crown was clinical acceptability (CAC), as judged by the treating dentist. A secondary outcome was "Goodness of Fit (GOF)," a composite score of several aspects of clinical fit, also judged by the study dentist. A mixed-effects logistic regression was used to analyze associations between laboratory technician ratings and the CAC and GOF. RESULTS: Dentists (n = 205) evaluated 3731 crowns. Technicians ranked the marginal detail of impressions as good or excellent in 92% of cases; other aspects of the impression were ranked good or excellent 88% of the time. Regarding tooth preparation, about 90% of preparations were considered adequate (neither excessive nor inadequate reduction). Factors associated with higher CAC were more preparation taper, and use of optical imaging. Factors associated with better GOF were higher impression quality, greater occlusal reduction, more preparation taper, and optical imaging. CONCLUSIONS: Overall quality of preparations and impressions was very high, as evaluated by laboratory technicians. Several clinical parameters were associated with higher CAC and GOF. Clinicians who struggle with crown remakes might consider less conservative tooth preparation, as well as using digital impression technology.

Concordance between practitioner questionnaire responses and observed clinical treatment recommendations for treatment of dentin hypersensitivity: findings from the National Dental Practice-Based Research Network.

BACKGROUND: Few published reports have presented concordance between treatment choices selected by dentists in hypothetical clinical scenarios and treatment choices made by the same dentists in actual clinical practice. The aim of the current cross-sectional study, conducted within the Management of Dental Hypersensitivity (MDH) study, was to assess the potential value of practitioners' questionnaire responses regarding their typical treatment provided for management of dentin hypersensitivity (DH), by evaluating agreement between these responses and subsequently-observed recommendations recorded during actual clinical examinations. METHODS: A total of 171 practitioners enrolled in the National Dental Practice-Based Research Network completed both a questionnaire and a clinical study regarding methods they use to treat dental hypersensitivity. The questionnaire solicited first-, second- and third-choice products when prescribing or recommending management of dentin hypersensitivity. Agreement was calculated for first-choice products/recommendations and for inclusion in the top three choices, as identified by the practitioners, from 11 listed treatment options. Overall percent agreement and Cohen's kappa statistic were calculated, with associated 95% confidence intervals (CI). Associations between practitioner characteristics and agreement were also evaluated. RESULTS: For individual treatment modalities, percentage agreement ranged from 63 to 99%, depending on the specific item. Percentage agreement between typical treatment and actual treatment for each practitioner's top three treatment modalities, as a combined grouping, ranged from 61 to 100%. When these same agreement pairings were quantified to account for agreement above that expected by chance, kappa values were poor to low. CONCLUSIONS: Concordance between hypothetical clinical scenarios and treatment choices made by the same dentists in actual clinical practice showed moderate to high levels of percentage agreement, but Cohen's kappa values suggested relatively low levels of agreement beyond that expected by chance. This analysis adds to the larger work of the network which has now observed a wide range of agreement between hypothetical and actual care, depending upon the specific diagnosis or treatment under consideration. Questionnaire data for DH might serve as a useful adjunct to clinical data regarding treatment recommendations, but agreement was not sufficiently high to justify use of questionnaires alone to characterize patterns of treatment for this particular condition.

Remake Rates for Single-Unit Crowns in Clinical Practice: Findings from The National Dental Practice-Based Research Network.

PURPOSE: Some crowns returned from the laboratory are clinically unacceptable, and dentists must remake them. The objectives of this study were to: (1) quantify the remake rate of single-unit crowns; and (2) identify factors significantly associated with crown remakes and intraoral fit. MATERIALS AND METHODS: Dentists participating in the National Dental Practice-Based Research Network recruited patients needing crowns and documented fabrication techniques, patient characteristics, and outcomes. Crowns were considered clinically acceptable or rejected. Also, various aspects of the clinical fit of the crown were graded and categorized as 'Goodness of Fit (GOF).' Dentist and patient characteristics were tested statistically for associations with crown acceptability and GOF. RESULTS: More than 200 dentists participated in this study (N = 205) and evaluated 3750 single-unit crowns. The mean age (years) of patients receiving a crown was 55. The remake rate for crowns was 3.8%. The range of rejection rates among individual practitioners was 0% to 42%. Most clinicians (118, or 58%) did not reject any crowns; all rejections came from 42% of the clinicians (n = 87). The most common reasons for rejections were proximal misfit, marginal errors, and esthetic failures. Fewer years in practice was significantly associated with lower crown success rates and lower fit scores. GOF was also associated with practice busyness and patient insurance status, patient gender (dentists reported better fit for female patients), and patient ethnicity. CONCLUSIONS: The crown remake rate in this study was about 4%. Remakes and crown GOF were associated with certain dentist and practice characteristics.

Impression Techniques Used for Single-Unit Crowns: Findings from the National Dental Practice-Based Research Network.

PURPOSE: To: (1) determine which impression and gingival displacement techniques practitioners use for single-unit crowns on natural teeth; and (2) test whether certain dentist and practice characteristics are significantly associated with the use of these techniques. MATERIALS AND METHODS: Dentists participating in the National Dental Practice-Based Research Network were eligible for this survey study. The study used a questionnaire developed by clinicians, statisticians, laboratory technicians, and survey experts. The questionnaire was pretested via cognitive interviewing with a regionally diverse group of practitioners. The survey included questions regarding gingival displacement and impression techniques. Survey responses were compared by dentist and practice characteristics using ANOVA. RESULTS: The response rate was 1777 of 2132 eligible dentists (83%). Regarding gingival displacement, most clinicians reported using either a single cord (35%) or dual cord (35%) technique. About 16% of respondents preferred an injectable retraction technique. For making impressions, the most frequently used techniques and materials are: poly(vinyl siloxane), 77%; polyether, 12%; optical/digital, 9%. A dental auxiliary or assistant made the final impression 2% of the time. Regarding dual-arch impression trays, 23% of practitioners report they typically use a metal frame tray, 60% use a plastic frame, and 16% do not use a dual-arch tray. Clinicians using optical impression techniques were more likely to be private practice owners or associates. CONCLUSIONS: This study documents current techniques for gingival displacement and making impressions for crowns. Certain dentist and practice characteristics are significantly associated with these techniques.

Preparation Techniques Used to Make Single-Unit Crowns: Findings from The National Dental Practice-Based Research Network.

PURPOSE: To: (1) determine which preparation techniques clinicians use in routine clinical practice for single-unit crown restorations; (2) test whether certain practice, dentist, and patient characteristics are significantly associated with these techniques. MATERIALS AND METHODS: Dentists in the National Dental Practice-Based Research Network participated in a questionnaire regarding preparation techniques, dental equipment used for single-unit crown preparations, scheduled chair time, occlusal clearance determination, location of finish lines, magnification during preparation, supplemental lighting, shade selection, use of intraoral photographs, and trimming dies. Survey responses were compared by dentist and practice characteristics using ANOVA. RESULTS: Of the 2132 eligible dentists, 1777 (83%) responded to the survey. The top two margin configuration choices for single-unit crown preparation for posterior crowns were chamfer/heavy chamfer (65%) and shoulder (23%). For anterior crowns, the most prevalent choices were the chamfer (54%) and the shoulder (37%) configurations. Regarding shade selection, a combination of dentist, assistant, and patient input was used to select anterior shades 59% of the time. Photographs are used to communicate shade selection with the laboratory in about half of esthetically demanding cases. The ideal finish line was located at the crest of gingival tissue for 49% of respondents; 29% preferred 1 mm below the crest; and 22% preferred the finish line above the crest of tissue. Average chair time scheduled for a crown preparation appointment was 76 ± 21 minutes. Practice and dentist characteristics were significantly associated with margin choice including practice type (p < 0.001), region (p < 0.001), and years since graduation (p < 0.001). CONCLUSIONS: Network dentists prefer chamfer/heavy chamfer margin designs, followed by shoulder preparations. These choices were related to practice and dentist characteristics.

Satisfaction with dental care among patients who receive invasive or non-invasive treatment for non-cavitated early dental caries: findings from one region of the National Dental PBRN.

BACKGROUND: The objectives were to: (1) quantify patient satisfaction with treatment for early dental caries overall, and according to whether or not (2a) the patient received invasive treatment; (2b) was high-risk for dental caries, and had dental insurance; and (3) encourage practitioners to begin using non-invasive approaches to early caries management. METHODS: Ten practitioners recorded patient, lesion, and treatment information about non-cavitated early caries lesions. Information on 276 consecutive patients with complete data was included, who received either non-invasive (no dental restoration) or invasive (dental restoration) treatment. Patients completed a patient satisfaction questionnaire and were classified as dissatisfied if they did not "agree" or "strongly agree" with any of 14 satisfaction items. RESULTS: Patients had a mean (± SD) age of 41.8 (±15.8) years, 64% were female and 88% were white. Twenty-five percent (n = 68) were dissatisfied in at least one of the 14 satisfaction items. Satisfaction levels did not significantly vary by patient's gender, race, caries risk category, or affected tooth surface location. Overall, 11% (28 of 276) received invasive treatment; satisfaction did not differ between patients who had invasive or non-invasive treatment. Seven patients received invasive treatment at their request even though that was not what their practitioner recommended; 5 out of 6 were satisfied with their treatment nonetheless. CONCLUSIONS: About one-fourth of patients treated for non-cavitated early caries were dissatisfied with at least some aspect of their dental care experience. Satisfaction of patients who received invasive treatment did not differ from those who received non-invasive treatment.

Management of Dentin Hypersensitivity by National Dental Practice-Based Research Network practitioners: results from a questionnaire administered prior to initiation of a clinical study on this topic.

BACKGROUND: Dentin hypersensitivity (DH) is a common problem encountered in clinical practice. The purpose of this study was to identify the management approaches for DH among United States dentists. METHODS: One hundred eighty five National Dental Practice-Based Research Network clinicians completed a questionnaire regarding their preferred methods to diagnose and manage DH in the practice setting, and their beliefs about DH predisposing factors. RESULTS: Almost all dentists (99%) reported using more than one method to diagnose DH. Most frequently, they reported using spontaneous patient reports coupled with excluding other causes of oral pain by direct clinical examination (48%); followed by applying an air blast (26%), applying cold water (12%), and obtaining patient reports after dentist's query (6%). In managing DH, the most frequent first choice was desensitizing, over-the-counter (OTC), potassium nitrate toothpaste (48%), followed by fluorides (38%), and glutaraldehyde/HEMA (3%). A total of 86% of respondents reported using a combination of products when treating DH, most frequently using fluoride varnish and desensitizing OTC potassium nitrate toothpaste (70%). The most frequent predisposing factor leading to DH, as reported by the practitioners, was recessed gingiva (66%), followed by abrasion, erosion, abfraction/attrition lesions (59%) and bruxism (32%). CONCLUSIONS: The majority of network practitioners use multiple methods to diagnose and manage DH. Desensitizing OTC potassium nitrate toothpaste and fluoride formulations are the most widely used products to manage DH in dental practice setting.

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 5,676 consecutive restorations inserted due to primary caries lesions on 3,751 patients. Practitioner-investigators placed a mean of 24.9 (SD = 12.4) restorations. Lesions were categorized as posterior proximal, anterior proximal, posterior occiusal, posterior smooth, or anterior smooth. Techniques used to diagnose the lesion were categorized as clinical assessment, radiographs, and/or optical. Statistical analysis utilized generalized 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.

Dentist and practice characteristics associated with restorative treatment of enamel caries in permanent teeth: multiple-regression modeling of observational clinical data from the National Dental PBRN.

PURPOSE: Current evidence in dentistry recommends non-surgical treatment to manage enamel caries lesions. However, surveyed practitioners report they would restore enamel lesions that are confined to the enamel. Actual clinical data were used to evaluate patient, dentist, and practice characteristics associated with restoration of enamel caries, while accounting for other factors. METHODS: Data from a National Dental Practice-Based Research Network observational study of consecutive restorations placed in previously unrestored permanent tooth surfaces and practice/demographic data from 229 participating network dentists were combined. ANOVA and logistic regression, using generalized estimating equations (GEE) and variable selection within blocks, were used to test the hypothesis that patient, dentist, and practice characteristics were associated with variations in enamel restorations of occlusal and proximal caries compared to dentin lesions, accounting for dentist and patient clustering. RESULTS: Network dentists from five regions placed 6,891 restorations involving occlusal and/or proximal caries lesions. Enamel restorations accounted for 16% of enrolled occlusal caries lesions and 6% of enrolled proximal caries lesions. Enamel occlusal restorations varied significantly (P < 0.05) by patient age and race/ethnicity, dentists' use of caries risk assessment, network region, and practice type. Enamel proximal restorations varied significantly (P < 0.05) by dentist race/ethnicity, network region, and practice type.

Strength comparison of four techniques to secure implant attachment housings to complete dentures.

STATEMENT OF PROBLEM: Implant overdentures become thinner and weaker after direct transfer of implant attachment housings. While much has been published on denture repair, these data do not directly apply to implant overdentures because the introduction of a metal housing changes the character of the repair. It is desirable to make a strong repair to avoid prosthesis fracture. PURPOSE: The purpose of this study was to compare the flexural strengths of 4 different methods for chairside direct transfer of implant attachment housings. MATERIAL AND METHODS: Eighty 11.5 × 9.1 × 39 mm heat-polymerized acrylic resin blocks were processed, assessed for porosities, and polished. An 8.5 mm diameter hole was drilled to a depth of 5 mm in the center of each block. Attachment housings were set into the bases with 4 different repair materials: autopolymerized acrylic resin (APAR), light-polymerized acrylic resin (LPAR), autopolymerized acrylic resin with silanated attachment housings (APSAH), and light-polymerized acrylic resin with silanated attachment housings (LPSAH). Blocks were immersed in water for 30 days in an incubator. A 3-point bend test was done in a universal testing machine, and load to fracture was recorded (MPa). Results were compared with 2-way ANOVA (α=.05). RESULTS: APSAH had the highest mean flexural strength at fracture (863.1 ±87 MPa) as compared to APAR (678.4 ±72.4 MPa), LPAR (550.9 ±119.3 MPa), and LPSAH (543.2 ±100.8 MPa). A comparison among the 4 groups showed that there were significant differences in maximum flexural strength (P<.001). The mean maximum strength of autopolymerized acrylic resin groups was significantly higher than light-polymerized acrylic resin groups. Silanation increased strength significantly compared to nonsilanated groups. CONCLUSIONS: The flexural strength of autopolymerized acrylic resin with silanated attachment housings was significantly higher than autopolymerized acrylic resin alone, light-polymerized acrylic resin alone, or light-polymerized acrylic resin with silanated attachment housings. Autopolymerized acrylic resin produced stronger constructs than light-polymerized materials.

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 5 regions: 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 1 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 fromactual 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.

Outcomes of root canal treatment in dental PBRN 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.

Cervical biopsy sampling variability in ALTS.

OBJECTIVE: To determine histologic sampling variability among clinical center colposcopists and quality control reviewers in the Atypical Squamous Cells of Undetermined Significance/Low-grade Squamous Intraepithelial Lesion Triage Study. MATERIALS AND METHODS: Clinical center colposcopists and quality control reviewers independently indicated need for biopsy, number of biopsies needed, and optimal biopsy location on customized computer software and digitized colposcopic images while examining subjects or monitoring colposcopists in the Atypical Squamous Cells of Undetermined Significance/Low-grade Squamous Intraepithelial Lesion Triage Study. Results were compared using percentages of agreement, κ statistics, McNemar, and paired t tests. RESULTS: Colposcopists and reviewers agreed whether a cervical biopsy was indicated for 2,631 (72.9%) of 3,610 evaluable subjects and 415 (91.6%) of 453 subjects with cervical intraepithelial neoplasia 2 or worse by histologic diagnosis. Only 3 of 41 colposcopists indicated 20% or greater of their biopsy sites to be more than 10 mm from reviewers' recommended sites. The mean of the greatest colposcopist-to-reviewer biopsy site distance was significantly greater than the mean maximum distance between reviewers' biopsy sites (14.9 vs 12.2 mm, p < .0001, respectively). Colposcopists indicated a significantly greater number of biopsy sites compared with consensus of reviewers (p < .0001). CONCLUSIONS: When cervical cancer precursors are present in women with minor cytologic abnormalities, most colposcopists obtain a biopsy. However, biopsy site placement can vary considerably. Only a minority of colposcopists sample significantly beyond recommended areas and less biopsy site variability occurs among experts.

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.

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.

A randomized clinical trial to compare diagnostic casts made using plastic and metal trays.

STATEMENT OF PROBLEM: Virtually every prosthodontic rehabilitation involves making diagnostic casts for analysis and prosthesis fabrication. Frequently, these casts are produced using irreversible hydrocolloid (IH) impression materials in stock metal or plastic trays. However, it is unclear whether one technique produces a more accurate cast. PURPOSE: The purpose of this randomized clinical trial was to compare the linear accuracy of diagnostic casts produced using IH with 1 of 3 different tray types: (1) perforated metal trays, (2) stock plastic trays, and (3) directed-flow stock plastic trays. All groups were compared to casts produced with custom trays and vinyl polysiloxane (VPS) impression materials, which were considered the control. MATERIAL AND METHODS: Seven subjects participated in this trial. IH impressions were made in a random order using 1 of 3 tray types: stock plastic, perforated metal, or plastic directed flow. These were compared to VPS impressions using custom trays (control group). Each impression technique was repeated 3 times per subject, for a total of 84 observations. Impressions were disinfected and poured in a type IV stone. Linear accuracy of casts was measured using computer software analysis of scanned images of the casts at x30 magnification. Three linear measurements were made on each cast: second molar to second molar, right second molar to left first premolar, and left second molar to right first premolar. Measurements were compared among techniques using mixed-model analysis of variance to account for correlation among the multiple measurements made on each subject. Dunnett's adjustment for multiple comparisons with control was used (α=.05). RESULTS: For molar-to-molar and right second molar to the left first premolar measurements, there were no significant differences in linear dimensions between casts made from different trays. However, linear measurements from the left second molar to the right first premolar demonstrated significant differences for casts made with stock metal, directed-flow, and stock plastic trays compared to custom trays. In this group, casts produced by stock metal, directed-flow, and stock plastic trays differed from controls by 102, 68, and 71 um, respectively. Generally, casts made with plastic trays (stock plastic and directed flow) had values closer to those of custom trays than did casts made with metal trays. CONCLUSIONS: Impressions made with irreversible hydrocolloid produced casts that were significantly different in linear dimension than casts produced by custom trays and VPS impressions. These differences were not uniform, but varied by location on the cast.

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.

Enhancement of bonding to enamel and dentin prepared by Er,Cr:YSGG laser.

BACKGROUND AND OBJECTIVE: Erbium lasers are potential tools to remove caries and dental hard tissue but bond strengths of composites to those preparations are reported to be lower than conventional methods. The purpose of this study was to evaluate the effect of mechanical excavation and/or chemical alteration on bond strength of composites to laser irradiated enamel and dentin. MATERIALS AND METHODS: Seventy-two premolars were ground to obtain flat enamel (E, n = 36) or dentin (D, n = 36) surfaces in both buccal and lingual cusps, divided into: LaserExcavation (LEx), LaserNo-excavation (LNex), and Bur (B) groups. The laser groups were irradiated for 10 seconds by Er,Cr:YSGG laser [4.5 W, 60% air, 80% water (enamel) 3 W, 60% air, 70% water (dentin)]. Irradiated surfaces in the excavation groups (Ex) were then mechanically smoothed with a dental excavator, prepared surfaces were then etched (37% H(3)PO(4)) for 20 or 40 seconds (enamel) and 15 or 30 seconds (dentin), washed (20 seconds), adhesive was applied(Single Bond Plus), and light cured (20 seconds). A composite cylinder (Filtek Supreme Plus) formed, placed and light cured (40 seconds). The specimens were stored (37 degrees C,48 hours), shear bond tested (1 mm/minute), and statistically analyzed (P < 0.05). RESULTS: Mixed-model ANOVA showed significant differences between enamel (P = 0.0091) and between dentin groups (P = 0.0035). Tukey/Kramer showed mean shear bond strength (SBS+/-SE) of EB40 (27.01+/-2.38 MPa) was significantly higher than ELNoExc20 (14.39+/-2.5 MPa) and ELExc40 (14.90+/-2.28 MPa). Also DB30 (17.57+/- 1.67 MPa) and DLExc30 (18.6+/-1.74 MPa) were significantly higher than DLNoExc15 (9.56+/-1.86 MPa). CONCLUSION: Increasing the etching time up to 40 seconds or excavation of the laser prepared surface (but not the combination) may increase the bond strength to the level of conventional methods in enamel but excavation has a greater influence in dentin. Also the combination of both methods [excavation+longer etching time (30 seconds)] exhibit significantly better results in dentin.Mode of failure study showed mechanical excavation in both enamel and dentin can significantly reduce the cohesive failure in tooth structure.

Development of a spiritually based educational program to increase colorectal cancer screening among African American men and women.

This study describes the development of a spiritually based intervention to increase colorectal cancer screening through African American churches by framing the health message with spiritual themes and scripture. The intervention development phase consisted of ideas from an advisory panel and core content identified in focus groups. In the pilot-testing phase, prototypes of the intervention materials were tested for graphic appeal in additional focus groups, and content was tested for acceptability and comprehension in cognitive interviews. Participants preferred materials showing a variety of African Americans in real settings, bright color schemes, and an uplifting message emphasizing prevention and early detection. Spiritual themes such as stewardship over the body, being well to serve God, and using faith to overcome fear, were well received. The materials were then finalized for implementation and will be used by community health advisors to encourage screening.