Prospective clinical evaluation of 765 partial glass-ceramic posterior restorations luted using photo-polymerized resin composite in conjunction with immediate dentin sealing.

OBJECTIVES: To evaluate the clinical performance of partial glass-ceramic (IPS e.max Press) posterior restorations. MATERIALS AND METHODS: A total of 765 restorations in 158 patients were placed between 2008 and 2018 and evaluated in a prospective study during regular dental care visits between 2015 and 2018. The restorations were luted with a conventional photo-polymerized resin composite (HFO) in conjunction with an Immediate Dentin Sealing procedure (IDS). Intra-oral photographs and radiographs were made and evaluated using USPHS criteria. RESULTS: The mean observation time was 53.3 months (range 3-113 months). Three absolute failures occurred (tooth fractures, n = 2; apical re-infection, n = 1) all leading to the loss of the restored tooth. Repairable and salvageable failures occurred in 9 teeth (endodontic complications, n = 7; secondary caries, n = 1; debonding, n = 1). The survival and success rates according to Kaplan-Meier after 5 years cumulated to 99.6% and 98.6%, respectively. Location (premolar/molar and mandibula/maxilla), pre-restorative endodontic status (vital/devitalised) and extension of the indirect ceramic restoration (number of sides and cusps involved) did not significantly affect the cumulative success rate (log rank test, p > 0.05). The condition of the vast majority of the restorations remained unaffected for 5 years. CONCLUSIONS: Partial glass-ceramic posterior restorations (pressed lithium disilicate (IPS e.max press, Ivoclar Vivadent) luted by means of a conventional photo-polymerized resin composite in conjunction with the use of an IDS procedure have an excellent medium-term prognosis. CLINICAL RELEVANCE: Partial glass-ceramic posterior restorations can be considered as a highly reliable treatment option. Location and extension of the restoration and pre-restorative endodontic status do not affect success rate.

Digital assessment of a retentive full crown preparation-An evaluation of prepCheck in an undergraduate pre-clinical teaching environment.

INTRODUCTION: Acquiring practical skills is essential for dental students. These practical skills are assessed throughout their training, both formatively and summatively. However, by means of visual inspection alone, assessment cannot always be performed objectively. A computerised evaluation system may serve as an objective tool to assist the assessor. AIM: The aim of the study was to evaluate prepCheck as a tool to assess students' practical skills and as a means to provide feedback in dental education. METHODS: As part of a previously scheduled practical examination, students made a preparation for a retentive crown on the maxillary right central incisor-tooth 11. Assessments were made four times by two independent assessors in two different ways: (a) conventionally and (b) assisted by prepCheck. By means of Cohen's kappa coefficient, agreements between conventional and digitally assisted assessments were compared. Questionnaires were used to assess how students experienced working with prepCheck. RESULTS: Without the use of prepCheck, ratings given by teachers differed considerably (mean κ = 0.19), whereas the differences with prepCheck assistance were very small (mean κ = 0.96). Students found prepCheck a helpful tool for teachers to assess practical skills. Extra feedback given by prepCheck was considered useful and effective. However, some students complained about too few scanners and too little time for practice, and some believed that prepCheck is too strict. CONCLUSION: prepCheck can be used to assist assessors in order to obtain a more objective outcome. Results showed that practicing with feedback from both prepCheck and the teacher contributes to an effective learning process. Most students appreciated prepCheck for learning practical skills, but introducing prepCheck requires enough equipment and preparation time.

Shear bond strength of two composite resin cements to multiphase composite resin after different surface treatments and two glass-ceramics.

AIM: To compare the shear bond strength (SBS) after aging of two dual-curing composite resin cements to multiphase composite resin (experiment) and glass-ceramics (control). METHODS: Seventy computer-aided design/computer-aided manufacturing (CAD/CAM) blocks were prepared: 24 multiphase composite resin blocks (Lava Ultimate; experiment), and 12 control blocks (groups 5 and 6: 6 IPS e.max CAD, 6 IPS Empress CAD). Surface treatments of the experiment groups were: 1) Al2O3 airborne particle abrasion; 2) bur-roughening; 3) silica-coated aluminum oxide particle abrasion; and 4) hydrofluoric (HF) acid etching. Per study group, Variolink II (a) and RelyX Ultimate (b) were used as cements. Per treatment group, four cement cylinders were adhered to the conditioned blocks (n = 12). After thermocyclic aging (10.000x, 5°C to 55°C), notch-edge shear testing was applied. Modes of failure were examined. A P value of 0.05 was considered significant. RESULTS: Groups 1a (18.68 ± 3.81) and 3a (17.09 ± 3.40) performed equally to 6a (20.61 ± 4.10). Group 5a (14.39 ± 2.80) did not significantly differ from groups 1a, 3a, and 4a (15.21 ± 4.29). Group 2a (11.61 ± 3.39) showed the lowest bond strength. For the RelyX Ultimate specimens, mean bond strengths were: 1b (18.12 ± 2.84) > 4b (15.57 ± 2.31) > 2b (12.34 ± 1.72) = 3b (11.54 ± 2.45) = 6b (12.31 ± 1.87) > 5b (0.78 ± 0.89). Failure mode analysis showed a significant association between bond strength values and modes of failure (chi-square). CONCLUSION: The SBS of the composite cements to the multiphase composite resin that was treated by Al2O3 or silica-coated aluminum oxide particle abrasion is comparable to the bond of the control groups.

Comparison of level of cognitive process between case-based items and non-case-based items of the interuniversity progress test of medicine in the Netherlands.

PURPOSE: It is assumed that case-based questions require higher order cognitive processing, whereas questions that are not case-based require lower order cognitive processing. In this study, we investigated to what extent case-based questions and questions that are not case-based, relate to Bloom's taxonomy. METHODS: In this article, 4800 questions of the Progress Test were classified whether it was a case-based question and the level of Bloom's taxonomy. Lower-order questions require students to remember or/and basically understand the knowledge. Higher-order questions require students to apply, analyze, or/and evaluate. A phi-coefficient was calculated to investigate the relations between the presence of case-based questions and the required level of cognitive processing. RESULTS: Our results demonstrated that case-based questions were measuring higher levels of cognitive processing in 98.1% of the questions. Of the non-case-based questions, 33.7% required a higher level of cognitive processing. The phi-coefficient demonstrated a significant moderate correlation between the presence of a patient case in a question and its required level of cognitive processing (phi-coefficient = 0.55, p<0.001). CONCLUSION: Medical teachers should be aware of the association between item formats (case-based versus non-case-based) and the cognitive processes they elicit in order to meet a certain balance in a test, taking the learning objectives as well as the test difficulty into account.

Autotransplantation of teeth with incomplete root formation: a systematic review and meta-analysis.

OBJECTIVES: The objective of this systematic review and meta-analysis was to determine the rates of survival and success and the complications related to autotransplantation of teeth with incomplete root formation. Additionally, we attempted to identify the prognostic factors that influence the outcome of tooth autotransplantation. MATERIALS AND METHODS: A literature search for all data published until July 2016 was conducted. Inclusion and exclusion criteria were specified. Risk of bias was assessed with the Newcastle checklist. Meta-analysis was performed by using the DerSimonian-Laird random effect model. The 1-, 5-, and 10-year survival rates and the weighted estimated survival, success, and complication rates per year were calculated. RESULTS: Thirty-two studies were included for analysis. The survival rates reported after 1, 5, and 10 years were 97.4, 97.8, and 96.3%, respectively. The annual weighted estimated survival rate (98.2%), success rate (96.6%), and complication rates in terms of ankylosis (2.0%), root resorption (2.9%), and pulp necrosis (3.3%) were analyzed. No firm conclusions could be drawn with respect to the prognostic factors due to insufficient evidence of high quality. CONCLUSION: The survival and success rates of autotransplantation of teeth with incomplete root formation were high (> 95%), with a low rate of complications (< 5%). CLINICAL RELEVANCE: Current evidence from the literature on autotransplantation of teeth with incomplete root formation shows favorable survival and success rates and low complication rates, indicating it is a reliable treatment option.

Effect of immediate dentine sealing on the fracture strength of lithium disilicate and multiphase resin composite inlay restorations.

PURPOSE: Limited information is available on the effect of Immediate Dentin Sealing (IDS) on the fracture strength of indirect partial posterior restorations. This study evaluated the effect of IDS on the fracture strength and failure types of two indirect restorative materials. MATERIALS AND METHODS: Standard MOD inlay preparations were made on sound molars (N=40, n=10 per group) and randomly divided into four groups to receive the inlay materials with and without the application of IDS: Group L-IDS-: Li2Si2O5 (Lithium disilicate, IPS e.max) without IDS; Group L-IDS+: Li2Si2O5 with IDS; Group MR-IDS-: Multiphase resin composite (MR, Lava Ultimate) without IDS; MR-IDS+: MR with IDS. Inlays made of L were etched with 5% hydrofluoric acid, and MR inlays were silica coated. After silanization, they were cemented using adhesive resin cement (Variolink Esthetic DC). The specimens were thermo-mechanically aged (1.2×106 cycles, 1.7Hz, 8000 cycles, 5-55°C) and then subjected to load to failure (1 mm/min). Failure types and locations of debondings were classified. Data were statistically analyzed using ANOVA, Mann Whitney U-test and Chi-square tests (α=0.05). Two-parameter Weibull distribution values including the Weibull modulus, scale (m) and shape (0), values were calculated. RESULTS: After aging conditions, no apparent changes were observed in marginal integrity but occlusal wear facets were more common with MR than with L (p<0.001). Material type and the application of IDS significantly affected the results (p=0.013). While group L-IDS- showed the lowest mean fracture strength (1358±506N) among all groups (p<0.05), application of IDS significantly increased the results significantly (L-IDS+: 2035±403N) (p=0.006). MR groups with and without IDS, did not show significant difference (MR-IDS-: 1861±423, MR-IDS+: 1702±596 N) (p=0.498). When materials without IDS are compared, L showed significantly lower results than that of MR (p=0.035). With the application of IDS, no significant difference was noted between L and MR materials (p=0.160). Weibull distribution presented the highest shape (0) for L-IDS+ (5.66) compared to those of other groups (3.01-4.76). Neither the material type (p=0.830), nor the application of IDS (p=0.54) affected the severity of the failure types. In 95% of the cases, the IDS layer left adhered on the tooth surface after fracture tests. In groups where no IDS was used, resin cement remained on the tooth surface in 44% of the cases (p=0.001). No significant differences were observed between the materials with respect to cement remnants or IDS after fracture (p=0.880). The incidence of repairable failure types (83%) was more common with L than with MR (75%) material (p>0.05). CONCLUSION: Immediate dentin sealing improves adhesion, and thereby the fracture strength of inlays made of lithium disilicate but not that multiphase resin composite.

Influence of feedback characteristics on perceived learning value of feedback in clerkships: does culture matter?

BACKGROUND: Various feedback characteristics have been suggested to positively influence student learning. It is not clear how these feedback characteristics contribute to students' perceived learning value of feedback in cultures classified low on the cultural dimension of individualism and high on power distance. This study was conducted to validate the influence of five feedback characteristics on students' perceived learning value of feedback in an Indonesian clerkship context. METHODS: We asked clerks in Neurology (n = 169) and Internal Medicine (n = 132) to assess on a 5-point Likert scale the learning value of the feedback they received. We asked them to record whether the feedback provider (1) informed the student what went well, (2) mentioned which aspects of performance needed improvement, (3) compared the student's performance to a standard, (4) further explained or demonstrated the correct performance, and (5) prepared an action plan with the student to improve performance. Data were analyzed using multilevel regression. RESULTS: A total of 250 students participated in this study, 131 from Internal Medicine (response rate 99%) and 119 from Neurology (response rate 70%). Of these participants, 225 respondents (44% males, 56% females) completed the form and reported 889 feedback moments. Students perceived feedback as more valuable when the feedback provider mentioned their weaknesses (ß = 0.153, p < 0.01), compared their performance to a standard (ß = 0.159, p < 0.01), explained or demonstrated the correct performance (ß = 0.324, p < 0.001) and prepared an action plan with the student (ß =0.496, p < 0.001). Appraisal of good performance did not influence the perceived learning value of feedback. No gender differences were found for perceived learning value. CONCLUSIONS: In Indonesia, we could validate four out of the five characteristics for effective feedback. We argue that our findings relate to culture, in particular to the levels of individualism and power distance. The recognized characteristics of what constitutes effective feedback should be validated across cultures.

Implant-supported mandibular removable partial dentures: Functional, clinical and radiographical parameters in relation to implant position.

BACKGROUND: Patients with a Kennedy class I situation often encounter problems with their removable partial denture (RPD). PURPOSE: To assess the functional benefits of implant support to RPDs, the clinical performance of the implants and teeth and to determine the most favorable implant position: the premolar (PM) or molar (M) region. MATERIALS AND METHODS: Thirty subjects received 2 PM and 2 M implants. A new RPD was made. Implant support was provided 3 months later. In a cross-over model, randomly, 2 implants (PM or M) supported the RPD during 3 months. Masticatory performance was assessed using the mixing ability index (MAI). Clinical and radiographic parameters were assessed. Non-parametric statistical analysis for related samples and post hoc comparisons were performed. RESULTS: Masticatory performance differed significantly between the stages of treatment (P < .001). MAI-scores improved with implant support although the implant position had no significant effect. No complications to the implants or RPD were observed and clinical and radiographical parameters for both implants and teeth were favorable. Higher scores for bleeding on probing were seen for molar implants. CONCLUSIONS: Implant support to a Kennedy class I RPD significantly improves masticatory function, regardless of implant position. No major clinical problems were observed.

Stock Versus CAD/CAM Customized Zirconia Implant Abutments - Clinical and Patient-Based Outcomes in a Randomized Controlled Clinical Trial.

BACKGROUND: Single-tooth replacement often requires a prefabricated dental implant and a customized crown. The benefits of individualization of the abutment remain unclear. PURPOSE: This randomized controlled clinical trial aims to study potential benefits of individualization of zirconia implant abutments with respect to preservation of marginal bone level and several clinical and patient-based outcome measures. MATERIAL AND METHODS: Fifty participants with a missing premolar were included and randomly assigned to standard (ZirDesign, DentsplySirona Implants, Mölndal, Sweden) or computer aided design/computer aided manufacturing (CAD/CAM) customized (Atlantis, DentsplySirona Implants, Mölndal, Sweden) zirconia abutment therapy. Peri-implant bone level (primary outcome), Plaque-index, calculus formation, bleeding on probing, gingiva index, probing pocket depth, recession, appearance of soft tissues and patients' contentment were assessed shortly after placement and one year later. RESULTS: No implants were lost and no complications related to the abutments were observed. Statistically significant differences between stock and CAD/CAM customized zirconia abutments could not be demonstrated for any of the operationalized variables. CONCLUSION: The use of a CAD/CAM customized zirconia abutment in single tooth replacement of a premolar is not associated with an improvement in clinical performance or patients' contentment when compared to the use of a stock zirconia abutment.

Implant-supported removable partial dentures in the mandible: A 3-16 year retrospective study.

PURPOSE: The purpose of this retrospective study was to assess performance, together with biological and technical complications, of implant-supported removable partial dentures (ISRPD) in mandibular Kennedy class I situations with implants placed in the anterior or posterior position. METHODS: 23 subjects with two endosseous implants to support a bilateral-free-ending mandibular removable denture were examined. Eight subjects had implants in the premolar (anterior) region and 15 subjects implants in the molar (posterior) region. Biological and technical complications were recorded from the patients' medical record. Patients filled out a validated questionnaire regarding their appreciation of oral health related quality of life (OHIP-NL49) and a VAS score on overall satisfaction. RESULTS: Over a mean follow-up period of 8 years (median 8 years, range 3-16 years) the cumulative implant survival rate was 91.7% (SE 0.05). Mean peri-implant bone loss was 0.9mm (SD 1.0mm). Scores for bleeding on probing, plaque and mucosal health were generally low, but significantly worse for posteriorly placed implants. Significantly more biological complications occurred in the posterior group (X2(1)=3.9; p=0.048). In 65% of the cases no technical complications were registered. Mean overall OHIP score was 16.1 (SD 18.4) and patients were highly satisfied (VAS: 8.4; SD 2.1). CONCLUSIONS: Within the limitations of this retrospective study, in case of a Kennedy class I situation in the mandible, an ISRPD is a viable treatment option with a high implant survival rate and satisfied patients after a maximum of 16 years. Technical and biological complications should be anticipated. Anteriorly placed implants performed slightly better.

Radiographic technique and brackets affect measurements of proximal enamel thickness on mandibular incisors.

OBJECTIVE: To investigate the influence of radiographic film and tube positioning, the presence and the size of brackets on in vitro measurements of proximal enamel thickness of mandibular incisors on periapical radiographs aimed to aid planning of interproximal enamel reduction procedures in orthodontics. MATERIALS AND METHODS: Eighty human mandibular incisors were assigned to sets of four and located in a customized base. Periapical radiographs were taken with the film positioned at three different angles (0°, 2°, and 5°) in relation to the frontal plane and the tube head positioned at five angles (0°, -2°, -5°, +2°, and +5°) in relation to the sagittal plane. The proximal enamel width was calculated by means of computerized image analysis and compared with measurements obtained at 0°. Statistical analysis was carried out to compare the enamel measurements on radiographs made with all angular combinations with and without the presence of brackets of different dimensions. RESULTS: A significant difference (P < 0.05) was found between the measurements of proximal enamel width obtained at the different angles in relation to the frontal and sagittal planes for all sets with or without brackets. The presence of brackets significantly affected the measured width only for the enamel side further away from the radiation source at the sagittal plane (P < 0.05). CONCLUSION: Angular changes in taking periapical radiographs of mandibular incisors and the presence of brackets significantly affect interproximal enamel measurements made with image analysis software.

Implant-supported mandibular removable partial dentures; patient-based outcome measures in relation to implant position.

OBJECTIVES: To assess the benefits of implant support to Removable Partial Dentures (RPD) in patients with a bilateral free-ending situation in the mandible and to determine the most favorable implant position: the premolar (PM) or the molar (M) region. METHODS: Thirty subjects with a bilateral unbounded posterior saddle received 2 PM and 2M implants. A new RPD was placed. Implant support was provided 3 months later. Two PM implants supported the RPD. After 3 months the 2M implants were used or vice versa. Outcome measures included oral health related quality of life (OHIP-NL49), general health status (SF-36), contentment assessed on a Visual Analogue Scale (VAS) and the number of hours that the RPD was worn. Data were collected prior to treatment, 3 months after having functioned with a new RPD and after 3 and 6 months with implant support. Finally, patients expressed their preferred implant position. RESULTS: The general health status (SF-36) was not influenced. OHIP-NL49 values and mean wearing-time were statistical significantly more favorable for ISRPD's, regardless of the implant position. Per day, the ISRPD's were worn 2-3h more than the unsupported new RPD. Patients' expectations were met as the VAS-scores of anticipated and realized contentment did not reach a statistical significant level (p>0.05). VAS scores for ISRPD's with M implant support were higher than for PM implant support. Finally, 56.7% of subjects preferred the M implant support, 13.3% expressed no preference and 30% opted for PM implant support. CONCLUSIONS: Mandibular implant support favorably influences oral health related patient-based outcome measures in patients with a bilateral free-ending situation. The majority of patients prefer the implant support to be in the molar region. CLINICAL SIGNIFICANCE: Patients with a bilateral free-ending situation in the mandible opposed by a maxillary denture benefit from implant support to their mandibular removable partial denture. Most patients prefer this support to be in the molar region.

Treatment comfort, time perception, and preference for conventional and digital impression techniques: A comparative study in young patients.

INTRODUCTION: The aim of this crossover study was to assess perceptions and preferences for impression techniques in young orthodontic patients receiving alginate and 2 different digital impressions. METHODS: Thirty-eight subjects aged 10 to 17 years requiring impressions for orthodontic treatment were randomly allocated to 3 groups that differed in the order that an alginate impressions and 2 different intraoral scanning procedures were administered. After each procedure, the patients were asked to score their perceptions on a 5-point Likert scale for gag reflex, queasiness, difficulty to breathe, uncomfortable feeling, perception of the scanning time, state of anxiety, and use of a powder, and to select the preferred impression system. Chairside time and maximal mouth opening were also registered. RESULTS: More queasiness (P = 0.00) and discomfort (P = 0.02) during alginate impression taking of the maxilla were perceived compared with the scans with the CEREC Omnicam (Sirona Dental Systems, Bensheim, Germany). There were no significant differences in perceptions between the alginate impressions and the Lava C.O.S. (3M ESPE, St Paul, Minn) and between the 2 scanners. Chairside times for the alginate impressions (9.7 ± 1.8 minutes) and the CEREC Omnicam (10.7 ± 1.8 minutes) were significantly lower (P <0.001) than for the Lava C.O.S. (17.8 ± 4.0 minutes). Digital impressions were favored by 51% of the subjects, whereas 29% chose alginate impressions, and 20% had no preference. Regardless of the significant differences in the registered times among the 3 impression-taking methods, the distributions of the Likert scores of time perception and maximal mouth opening were similar in all 3 groups. CONCLUSIONS: Young orthodontic patients preferred the digital impression techniques over the alginate method, although alginate impressions required the shortest chairside time.

Development of cognitive processing and judgments of knowledge in medical students: Analysis of progress test results.

BACKGROUND: Beside acquiring knowledge, medical students should also develop the ability to apply and reflect on it, requiring higher-order cognitive processing. Ideally, students should have reached higher-order cognitive processing when they enter the clinical program. Whether this is the case, is unknown. We investigated students' cognitive processing, and awareness of their knowledge during medical school. METHODS: Data were gathered from 347 first-year preclinical and 196 first-year clinical students concerning the 2008 and 2011 Dutch progress tests. Questions were classified based upon Bloom's taxonomy: "simple questions" requiring lower and "vignette questions" requiring higher-order cognitive processing. Subsequently, we compared students' performance and awareness of their knowledge in 2008 to that in 2011 for each question type. RESULTS: Students' performance on each type of question increased as students progressed. Preclinical and first-year clinical students performed better on simple questions than on vignette questions. Third-year clinical students performed better on vignette questions than on simple questions. The accuracy of students' judgment of knowledge decreased over time. CONCLUSIONS: The progress test is a useful tool to assess students' cognitive processing and awareness of their knowledge. At the end of medical school, students achieved higher-order cognitive processing but their awareness of their knowledge had decreased.

Papillary fill response in single-tooth implants using abutments of different geometry.

OBJECTIVE: To evaluate the influence of abutment geometry on papillary fill in the esthetic zone in a delayed crown protocol. MATERIALS AND METHODS: Twenty-six subjects received two non-adjacent endosseous implants in the esthetic zone. Functional temporary crowns were installed 17-19 weeks later, using conventional (control) and curved (experimental) abutments. The abutments were randomized in each patient independently. Final crowns were cemented after 2 months (T0). Standard intraoral photographs and radiographs were made to evaluate papillary fill after 12 months (T12). The interproximal papilla fill was measured by means of the papilla index score (PIS) and related to the maximum bone level between the implant and the adjacent root as well as the peri-implant marginal bone level at T12, both measured radiographically. RESULTS: No statistically significant difference between the experimental and the control group could be demonstrated (P = 0.25). Ordinal regression analysis showed a positive correlation between the maximum bone level and papilla fill (P < 0.01) and a negative correlation between the peri-implant marginal bone level and papilla fill (P < 0.05). CONCLUSION: A concave abutment does not exhibit a better fill of the papilla compared with a straight abutment in single-tooth implant placement using a delayed protocol in the esthetic zone after 12 months of function.

Cumulative versus end-of-course assessment: effects on self-study time and test performance.

CONTEXT: Students tend to postpone preparation for a test until the test is imminent, which raises various risks associated with 'cramming' behaviours, including that for suboptimal learning. Cumulative assessment utilises spaced testing to stimulate students to study more frequently and to prevent procrastination. This randomised controlled study investigated how cumulative assessment affects time spent on self-study and test performance compared with end-of-course assessment. METHODS: A total of 78 undergraduate medical students in a Year 2 pre-clinical course were randomly assigned to either of two conditions. Students in the cumulative assessment condition were assessed in weeks 4, 8 and 10. Students in the end-of-course assessment condition were assessed in week 10 only. Each week, students reported the number of hours they spent on self-study. RESULTS: Students in the cumulative assessment condition (n = 25) spent significantly more time on self-study than students in the end-of-course assessment condition (n = 37) in all weeks of the course except weeks 5, 9 and 10. Overall, the cumulative assessment group spent 69 hours more on self-study during the course than did the control group, although the control group spent 7 hours more in studying during the final week of the course than did the cumulative assessment group. Students in the cumulative assessment condition scored slightly higher on questions concerning the content of the last part of the course. CONCLUSIONS: Cumulative assessment encourages students to distribute their learning activities over a course, which leaves them more opportunity to study the content of the last part of the course prior to the final examination. There was no evidence for a short-term effect of cumulative assessment on overall knowledge gain. We hypothesise that larger positive effects might be found if retention were to be measured in the long term.

Digital versus analog complete-arch impressions for single-unit premolar implant crowns: Operating time and patient preference.

STATEMENT OF PROBLEM: Digital impression-making techniques are supposedly more patient friendly and less time-consuming than analog techniques, but evidence is lacking to substantiate this assumption. PURPOSE: The purpose of this in vivo within-subject comparison study was to examine patient perception and time consumption for 2 complete-arch impression-making methods: a digital and an analog technique. MATERIAL AND METHODS: Fifty participants with a single missing premolar were included. Treatment consisted of implant therapy. Three months after implant placement, complete-arch digital (Cerec Omnicam; Sirona) and analog impressions (semi-individual tray, Impregum; 3M ESPE) were made, and the participant's opinion was evaluated with a standard questionnaire addressing several domains (inconvenience, shortness of breath, fear of repeating the impression, and feelings of helplessness during the procedure) with the visual analog scale. All participants were asked which procedure they preferred. Operating time was measured with a stopwatch. The differences between impressions made for maxillary and mandibular implants were also compared. The data were analyzed with paired and independent sample t tests, and effect sizes were calculated. RESULTS: Statistically significant differences were found in favor of the digital procedure regarding all subjective domains (P<.001), with medium to large effect sizes. Of all the participants, over 80% preferred the digital procedure to the analog procedure. The mean duration of digital impression making was 6 minutes and 39 seconds (SD=1:51) versus 12 minutes and 13 seconds (SD=1:24) for the analog impression (P<.001, effect size=2.7). CONCLUSIONS: Digital impression making for the restoration of a single implant crown takes less time than analog impression making. Furthermore, participants preferred the digital scan and reported less inconvenience, less shortness of breath, less fear of repeating the impression, and fewer feelings of helplessness during the procedure.

Cumulative assessment: strategic choices to influence students' study effort.

BACKGROUND: It has been asserted that assessment can and should be used to drive students' learning. In the current study, we present a cumulative assessment program in which test planning, repeated testing and compensation are combined in order to influence study effort. The program is aimed at helping initially low-scoring students improve their performance during a module, without impairing initially high-scoring students' performance. We used performance as a proxy for study effort and investigated whether the program worked as intended. METHODS: We analysed students' test scores in two second-year (n = 494 and n = 436) and two third-year modules (n = 383 and n = 345) in which cumulative assessment was applied. We used t-tests to compare the change in test scores of initially low-scoring students with that of initially high-scoring students between the first and second subtest and again between the combined first and second subtest and the third subtest. During the interpretation of the outcomes we took regression to the mean and test difficulty into account. RESULTS: Between the first and the second subtest in all four modules, the scores of initially low-scoring students increased more than the scores of initially high-scoring students decreased. Between subtests two and three, we found a similar effect in one module, no significant effect in two modules and the opposite effect in another module. CONCLUSION: The results between the first two subtests suggest that cumulative assessment may positively influence students' study effort. The inconsistent outcomes between subtests two and three may be caused by differences in perceived imminence, impact and workload between the third subtest and the first two. Cumulative assessment may serve as an example of how several evidence-based assessment principles can be integrated into a program for the benefit of student learning.

The effect of implementing undergraduate competency-based medical education on students' knowledge acquisition, clinical performance and perceived preparedness for practice: a comparative study.

BACKGROUND: Little is known about the gains and losses associated with the implementation of undergraduate competency-based medical education. Therefore, we compared knowledge acquisition, clinical performance and perceived preparedness for practice of students from a competency-based active learning (CBAL) curriculum and a prior active learning (AL) curriculum. METHODS: We included two cohorts of both the AL curriculum (n=453) and the CBAL curriculum (n=372). Knowledge acquisition was determined by benchmarking each cohort on 24 interuniversity progress tests against parallel cohorts of two other medical schools. Differences in knowledge acquisition were determined comparing the number of times CBAL and AL cohorts scored significantly higher or lower on progress tests. Clinical performance was operationalized as students' mean clerkship grade. Perceived preparedness for practice was assessed using a survey. RESULTS: The CBAL cohorts demonstrated relatively lower knowledge acquisition than the AL cohorts during the first study years, but not at the end of their studies. We found no significant differences in clinical performance. Concerning perceived preparedness for practice we found no significant differences except that students from the CBAL curriculum felt better prepared for 'putting a patient problem in a broad context of political, sociological, cultural and economic factors' than students from the AL curriculum. CONCLUSIONS: Our data do not support the assumption that competency-based education results in graduates who are better prepared for medical practice. More research is needed before we can draw generalizable conclusions on the potential of undergraduate competency-based medical education.