Psychosocial impact, perceived stress and learning effect in undergraduate dental students during transition from pre-clinical to clinical education.

INTRODUCTION: This study aimed to develop a suitable instrument for a comprehensive quantitative and qualitative assessment of perceived psychosocial impact, levels of stress and learning effect in undergraduate dental students during the transition from pre-clinical to clinical education. These findings might improve curricular structures and didactic organisation during this period. MATERIALS AND METHODS: At the beginning of their first clinical year, undergraduate dental students were asked to complete an anonymous forty-item questionnaire. Two hundred and seventy-six undergraduate dental students were willing to participate and completed the questionnaire and participated during the years 2011-2016. RESULTS: The response rate was between 45% and 96%. Correlational analysis (Spearman-Rho) in the field of psychosocial impact showed the dental teacher to be the most important multiplier of students' feelings. If the students feel that their teacher acts cooperatively, positive items increase and negative items decrease significantly (P < .0001). Also, students who report high levels of stress are affected significantly in their psychosocial interaction (P < .0001). Wilcoxon test yielded highest levels of stress in endodontology during the first weeks (P < .0001). During the same period, the greatest learning increment was seen for diagnostics and caries excavation. CONCLUSION: In conclusion, teaching of undergraduate dental students during the transition period from pre-clinical to clinical education can be positively influenced by a supportive learning environment and by specific chronological modifications in the curriculum. Students should start their clinical training with diagnostics, preventive dentistry and initial periodontal treatment. Due to high levels of perceived stress, endodontology should be introduced later in the clinical curriculum.

Novel Microscalpels for Removing Proximal Composite Resin Overhangs on Class II Restorations.

INTRODUCTION: Limited access to interdental spaces complicates removal of excess material when placing class II composite resin restorations. Evidence-based recommendations on interproximal finishing are rare. We present novel microscalpels for this indication. The aim of the study was to test their fracture strength and cutting ability and to compare microscalpels with the use of a scaler, oscillating devices (G5-ProShape, G5-Proxocare), finishing strips and scalpels of sizes 12, 15, and 21 in a standardized in vitro model. METHODS AND MATERIALS: Fracture strength (LOAD) and cutting forces (CUT) of microscalpels were evaluated at different angles (15, 30, 60, and 75 degrees; n=30 each) in a universal testing machine. Devices were compared in vitro using standardized composite overhangs. Marginal quality (QUAL; n=30) and quantity of excess/deficit (QUAN; n=30) were evaluated using scanning electron microscopy (SEM) for each device (explorative data analysis, Student t-test or analysis of variance; post hoc Scheffé). RESULTS: Microscalpels showed the highest LOAD (95.8 [5.0] N) (mean [standard deviation]) and easiest cutting (CUT) (7.6 [1.5]) at 15 degrees. At all angles, LOAD was significantly higher than CUT (p<0.001). Perfect margins were seen most often with scalpel size 12 (QUAL: 37% relative frequency), while most excess (73.4%) was observed with finishing strips. QUAN was lowest with microscalpels (19.3 [4.4] µm) and highest with finishing strips (116.0 [18.8]). Use of scalers led to fractures and crack formation. CONCLUSION: Microscalpels are able to cut composite at a lower force than necessary to fracture the blades at all angles. Small and/or curved scalpels yield the best-quality margins.

Professional Variability in Decision Making in Modern Dentistry: A Pilot Study.

Dental treatment planning is usually expected to take account of the individual patient's clinical risks and benefits. Ideally, the therapeutic choice for each and every patient should be based on adequate clinical diagnostics and risk assessment that facilitates stabilization of the patient's clinical condition as well as prevents further oral impairment. However, identification of the most suitable approach tends to become more and more challenging as the number of therapeutic alternatives continues to increase due to medical innovation. In this study, the challenge of decision making in modern dentistry is illustrated using the example of bounded edentulous spaces. Many therapeutic alternatives exist for such clinical scenarios, including a noninvasive monitoring approach, minimally invasive tooth recontouring, orthodontic and prosthodontic treatment, and implant placement. The findings of this pilot study highlight the utmost relevance of incorporating individual patients' needs and risks into clinical treatment planning and providing appropriate guidelines.

Effect of endurance training on dental erosion, caries, and saliva.

The aim of this investigation was to give insights into the impact of endurance training on oral health, with regard to tooth erosion, caries, and salivary parameters. The study included 35 triathletes and 35 non-exercising controls. The clinical investigation comprised oral examination, assessment of oral status with special regard to caries and erosion, saliva testing during inactivity, and a self-administered questionnaire about eating, drinking, and oral hygiene behavior. In addition, athletes were asked about their training habits and intake of beverages and sports nutrition. For saliva assessment during exercise, a subsample of n = 15 athletes volunteered in an incremental running field test (IRFT). Athletes showed an increased risk for dental erosion (P = 0.001). No differences were observed with regard to caries prevalence and salivary parameters measured during inactivity between athletes and controls. Among athletes, a significant correlation was found between caries prevalence and the cumulative weekly training time (r = 0.347, P = 0.04). In athletes after IRFT and at maximum workload, saliva flow rates decreased (P = 0.001 stimulated; P = 0.01 unstimulated) and saliva pH increased significantly (P = 0.003). Higher risk for dental erosions, exercise-dependent caries risk, and load-dependent changes in saliva parameters point out the need for risk-adapted preventive dental concepts in the field of sports dentistry.

Proximal box elevation with resin composite and the dogma of biological width: clinical R2-technique and critical review.

Provided that moisture control is possible, today's resin composite materials can be applied successfully in the restorative treatment of extensively decayed teeth. This suggests that restorative margins will be increasingly located below the cementoenamel junction, probably invading biological width. The recently introduced technique of proximal box elevation (PBE) offers the possibility of performing a stepwise elevation of deep proximal cavities to create more favorable preparation margins for direct or indirect restorations. Clinical instructions for the restoration of extensively damaged teeth are given through this presentation. A two-step R2-technique will be shown, and a critical review of the dogma of biological width will be presented.

Improving the mechanical properties of multiuse dental floss holders.

OBJECTIVES: This study was designed to determine the effect of using a tensioning device and various winding techniques on the tension of a polytetrafluorethylene (PTFE) floss in a multiuse holder. The hypothesis of this study is that the use of a tensioning device improves the handling and mechanical properties of floss holders. MATERIALS AND METHODS: The floss holder was modified so that four different degrees of tension (single-/double-wound; with/without tensioning device) were obtained and tested in an in vitro model approximating dental proximal contact resistance. The following parameters were measured: (I) the force (N) necessary to pass through the proximal contact after the 30th passage, (II) the displacement of the floss (mm), (III) the loosening of the floss (offset, mm), (IV) the change in distance between the branches (mm). RESULTS: (I) passage force. All modifications reached 11 N (median). For the double-wound modification using the tensioning device, the smallest displacement (II) was 3.6 mm; the single-wound modification without the tensioning device had the highest displacement (7.6 mm, medians) (III). The offset of all four different modifications ranged between 0 and -2 mm (medians). For the modification without the tensioning device, there was a difference in offset of -2 mm (single-wound) and 0.5 mm (double-wound) (medians). Modifications with the tensioning device did not produce any offset differences. (IV) A change in distance between the branches between -3 mm and -2 mm, respectively (with the tensioning device), and 0 mm (without the tensioning device) was observed (median). The results indicated that double-wound floss and the use of a tensioning device both lead to a constant tension of the floss in the floss holder. CONCLUSIONS: Technical modifications such as those shown in this study should improve the mechanical properties of multiuse floss holders, which, in turn, could lead to more user-friendly floss holders and hence to higher user acceptance.

Amplification of minute amounts of oral bacterial DNA for real-time quantitative PCR analysis.

BACKGROUND: High-throughput technologies for typing caries or health-associated bacterial populations including PCR, DNA microarrays and next-generation sequencing techniques require significant amounts of bacterial DNA. In clinical settings, the amount of sampled DNA is often limited and amplification is therefore essential. Protocols should be able to reproducibly amplify sequences in order to maintain initial sequence ratios and should not bias the representation of particular DNA sequence types. METHODS: A linear amplification protocol using DNA polymerase I was modified to permit the amplification and subsequent analysis of small amounts of bacterial DNA. The protocol was tested on human oral bacterial biofilms from different sources, including carious dentine and plaque, and compared to amplification by degenerate PCR of 16S rDNA sequences. Real-time quantitative PCR of 24 bacterial species was used as a readout system to test amplified DNA against unamplified DNA. RESULTS: The amplification protocol reliably yielded 5-10 µg DNA from as little as 12.5 ng of template DNA. Correlation coefficients between real-time quantitative PCR results from amplified and unamplified DNA were between 0.78 and 0.98. CONCLUSION: The optimized protocol consistently produced amplification products from minute amounts of bacterial DNA from caries and plaque; the amplification products are suitable for downstream genetic analyses.

[Suggestion for a classification of odontalgias]. / Vorschlag einer Klassifikation der Odontalgien.

BACKGROUND: Toothache prevalence in the overall population is considerable. However, for clinical purposes, the classification schemes available do not appear to be sufficiently sophisticated. Moreover, not all known forms of dental pain are considered. A refined classification that meets current standards is therefore introduced. To facilitate diagnosis, the characteristic features of the various types of odontalgia are summarized. RESULTS: The new classification differentiates among seven different origins of pain: 1. dentinal pain (originating from the pulpal tissues), 2. pulpal pain (originating from the pulpal tissues), 3. periodontal pain, 4. alveolar-osseous pain, 5. atypical odontalgia, 6. heterotopic dental pain, 7. odontalgia associated with primary psychosocial factors. CONCLUSIONS: In our opinion, the proposed classification differentiates among the different forms of odontalgia more precisely than all previous ones. However, its viability and advantages over other available classification schemes still need to be verified in daily practice.

Elevation of collagen type I in fibroblast-keratinocyte cocultures emphasizes the decisive role of fibroblasts in the manifestation of the phenotype of cyclosporin A-induced gingival overgrowth.

BACKGROUND AND OBJECTIVE: Collagen type I elevation in cyclosporin A-induced gingival overgrowth supports evidence that gingival fibroblasts play a decisive role in the manifestation of the phenotype. To analyze the role of gingival fibroblasts under more in vivo-like conditions, we evaluated the effect of cyclosporin A on collagen type I gene and protein expression in gingival overgrowth-derived gingival fibroblasts established as cocultures with gingival keratinocytes as well as in matched gingival fibroblast monolayers. MATERIAL AND METHODS: Monolayers and cocultures of primary gingival fibroblasts were treated with cyclosporin A for 6 and 72 h. The expression of collagen type I mRNA was analyzed by quantitative real time polymerase chain reaction, while expression and secretion of collagen type I protein was analyzed by indirect immunofluorescence and western blotting. RESULTS: Compared with controls, significant elevation of collagen type I mRNA was restricted to cocultures after 6 and 72 h of treatment with cyclosporin A. In keratinocytes, collagen type I remained undetectable. In monolayers and cocultures, indirect immunofluorescence showed a slightly higher level of collagen type I protein in gingival fibroblasts in response to stimulation with cyclosporin A. Semiquantitative detection of collagen type I by western blotting demonstrated a nonsignificant increase for cell extracts in monolayers and cocultures. For secreted collagen type I, western blot analysis of the supernatants revealed elevated protein levels in cultures stimulated with cyclosporin A. Compared with the corresponding monolayers, the stimulatory effect of cyclosporin A on protein secretion was significant only in coculture. CONCLUSION: Our results indicate that collagen type I is a target of cyclosporin A and that gingival fibroblasts are decisive for the manifestation of the gingival overgrowth-phenotype. Furthermore, the results suggest that cocultures of gingival overgrowth-derived gingival fibroblasts and gingival keratinocytes permit analysis of cyclosporin A-induced effects under more in vivo-like conditions.

Digital enhancement of radiographs for assessment of interproximal dental caries.

OBJECTIVES: Evaluation of a particular digital caries image-enhancing mode (filter) for its effect on the validity of measurements of caries lesion depth. METHODS: Standardized radiographs of 44 extracted teeth exhibiting interproximal caries lesions were obtained. Six radiographs were obtained of each tooth and digitized. Four radiographs were made using D-speed film with and without soft tissue scattering equivalent (STSE) at normal exposure time (0.32 s) and underexposed (0.16 s). Two were made using E-speed film with STSE normally (0.16 s) and underexposed (0.08 s). On each of the 264 radiographs, 4 independent examiners measured the central depth (CD) of 1 carious lesion per tooth both on the unchanged radiographic image and after use of the filter. Histometric CD assessments provided a gold standard for comparison with the radiographic measurements (validity). Repeated measures ANOVA was calculated for validity in relation to examiner, lesion type, filter, film type, exposure time and STSE. RESULTS: The lesion type was identified to statistically significantly influence the validity of CD measurements. Examiner in combination with defect type (P<0.001), filter (P = 0.017), exposure (P = 0.027) and film type (P = 0.044) had an additional albeit small effect. CONCLUSIONS: The lesion type significantly influenced the validity of CD measurements: enamel lesions were less underestimated than dentin lesions.

Double-blind study on materials testing with applied kinesiology.

Applied Kinesiology (AK) is a scientifically unproven method used in complementary medicine to recognize the (in)tolerance of dental materials. Test-retest reliability of AK was examined. The working hypothesis was the assumption that the reliability of AK would not exceed random chance. Two dentists qualified in AK examined 112 volunteers to determine individual (in)tolerance toward two dental composite materials. After the first examination, 31 subjects were excluded from further testing. At the end of the open test phase, 34 of 81 participants had been classified as "tolerant", and seven as "intolerant" to both materials. The remaining 40 individuals showed a combination of either tolerant (to material I)/intolerant (to material II), or the reverse (n = 20 each). Retrieval rate was tested under blind conditions. In 14 cases, the results of the open and blinded tests matched, whereas in 26 cases they did not (95% confidence interval, 21%-52%; p = 0.98). This outcome confirmed our working hypothesis.

[Ill due to amalgam? 10 rules for managing the symptomatic patient]. / Krank durch Amalgam? Zehn Regeln für den Umgang mit Betroffenen.

Over the past two decades, mercury released by amalgam fillings has been held responsible for a number of mental and somatic health complaints. However, a systematic relation between increased mercury levels and the severity of the reported symptoms has never been demonstrated in any of the present well-controlled multidisciplinary studies. These studies, however, have found a high prevalence of mental disorders, especially somatization syndromes, among patients with self-diagnosed "amalgam illness". Additionally, our own studies indicate that amalgam anxiety is often merely one aspect of a general environmental anxiety. Overall, the present findings suggest a psychological etiology for amalgam-related complaints. Our psychosomatic model of "amalgam illness" integrates external factors, individual predispositions and specific processes of perception, awareness, evaluation and attribution. Practical management strategies for primary care physicians can be derived from this model.

Nanoleakage at the composite-dentin interface: a review.

The term "nanoleakage" was introduced to describe a specific type of leakage within the dentin margins of restorations. Nanoleakage appears as a consequence of the acid etching procedure allowing the penetration of oral and pulpal liquids such as acids into porosities within or adjacent to the hybrid layer. Nanoleakage is independent from microleakage. The amount of penetration depends on the type of bonding agent and on different parameters of the application technique (e.g. etching time, dentin moisture). Nanoleakage is much less extensive than microleakage and has probably no short-term clinical relevance. The long-term stability of the adhesive bond between dentin and restorative material, however, might be adversely affected. Nevertheless, based on the knowledge to date, acid etching prior to dentin bonding should be performed.

A clinical study to compare the efficacy of 2 electric toothbrushes in plaque removal.

OBJECTIVES: To compare the cleaning efficacy of a powered toothbrush with 3-dimensional brush head action (Braun Oral-B 3D Plaque Remover D15) and a high-speed "microtation" brush with an additional "microbrush-clip" (Rowenta Dentasonic MH921S). MATERIAL AND METHODS: 82 healthy subjects took part in the study. After a familiarization period of 8 days, the subjects abstained from all oral hygiene procedures for 48 h. After plaque was scored, the subjects brushed their teeth under supervision with the two brushes according to a split-mouth design. Immediately after brushing, subjects completed a questionnaire and plaque was scored again. RESULTS: The overall plaque scores were found to be significantly reduced from 3.05+/-0.60 to 1.96+/-0.63 by the D15 and from 3.02+/-0.58 to 2.24+/-0.64 by the Dentasonic (p<0.05). The proximal surface plaque scores were reduced from 3.20+/-0.63 to 2.17+/-0.69 by the D15 and from 3.17+/-0.60 to 2.44+/-0.69 by the Dentasonic. The relative plaque reduction was overall 36.6+/-12.2% for the D15 compared to 26.1+/-13.5% for the Dentasonic and at proximal surfaces, 33.1+/-12.3% and 23.2+/-13.0%, respectively. 75% of the subjects stated that they would prefer to keep the D15. CONCLUSIONS: Both brushes were able to remove a significant amount of plaque, but the D15 was significantly more effective compared to the Dentasonic. The additional "microbrush-clip" for the proximal embrasures failed to improve plaque removal from these tooth surfaces, compared to the D15 alone.

Influence of rubber-dam on the reconstruction of proximal contacts with adhesive tooth-colored restorations.

PURPOSE: To clinically measure the influence of rubber-dam on the proximal contact strength after its reconstruction with tooth-colored restorations. MATERIALS AND METHODS: The frictional forces during the removal of a metal strip from the proximal contact area were taken as measure for the proximal contact strengths of 46 restorations (35 ceramic inlays, 11 direct composite restorations). The teeth were separated with a rubber-dam and wedged thoroughly during the complete reconstruction procedure according to the multiple wedging technique. The proximal contact strengths were measured immediately before and immediately after removing the rubber-dam. RESULTS: The contact strengths were statistically significantly lower immediately after the removal of the rubber-dam (1.07+/-0.82N) compared to the situation with the rubber-dam (1.99+/-1.21N). The amount of the reduction after removing the rubber-dam was statistically significantly higher between the second premolar and the first molar (1.45+/-1.06N) compared to the contacts between the canines and the first premolar (0.32+/-0.44N) and the first and second premolar (0.59+/-0.77N). No influence of the restorative material, the use and localization of retainers, localization of the restoration, or number of teeth under the rubber-dam was detectable. CONCLUSION: Rubber-dam is recommended for adhesive restorations as it is helpful for achieving good adhesion between the tooth and restorative materials. Nevertheless, the application of rubber-dam seems to be a factor which complicates the reconstruction of adequate proximal contacts.

Reliability of assessing interproximal bone loss by digital radiography: intrabony defects.

AIM: The aim of the present study was to assess the reproducibility and validity of linear measurements of interproximal bone loss in intrabony defects on digitized radiographic images after application of different filters and magnifications. METHODS: Immediately before surgery 50 radiographs of 50 periodontally diseased teeth exhibiting interproximal intrabony defects were obtained by a standardized technique in 50 patients. Intrasurgically the distances from the cementoenamel-junction (CEJ) to the alveolar crest (AC) and from the CEJ to the deepest extension of the bony defect (BD) were assessed. All radiographs were digitized by a flatbed scanner (resolution: 600x1200 dpi). Using the FRIACOM-soft ware, the linear distances CEJ to AC and CEJ to BD were measured at 50 intrabony defects on digitized but unchanged radiographic images and also after use of 2 different basic image processing modes (filters: enhancement of grey level differences, spreading of grey values) with 7-fold and 14-fold magnification by 2 different examiners. RESULTS: Repeated measures MANOVA revealed reproducibility of the measurement of the distance CEJ to AC to be significantly influenced by examiner (p=0.027) and filter in combination with the height of 2 wall component of the intrabony defect (p=0.066). For the distance CEJ to BD filters had significant influence on reproducibility in correlation with vertical angulation difference (p=0.001). On the average in this study radiographic measurements tended to overestimate the amount of bone loss as assessed by intrasurgical measurements (CEJ-AC: 0.74-1.91 mm; CEJ-DB: -0.04-0.77 mm). Validity of measurement of the distance CEJ-AC was shown to be significantly influenced by the depth of the intrabony defect (p<0.003). Validity of the distance CEJ-BD was significantly influenced by intrasurgically assessed bone loss (p=0.029), horizontal angulation (p=0.066). Filters influenced the validity only in combination with examiner (p<0.001). CONCLUSIONS: In this study, the chosen digital manipulations (filters: spreading, structure) of radiographic images failed to result in statistically significantly more reproducible or valid measurements of interproximal bone loss within intrabony defects when compared to the digitized but unchanged images. All radiographic assessments on the digitized images except for use of enhancement of grey level differences (structure) came close to the intrasurgical gold standard.

Computer-based intraoral image analysis of the clinical plaque removing capacity of 3 manual toothbrushes.

BACKGROUND: (I) Introducing an intraoral camera system with a special positioner to allow computer-based analysis of reproducible images on lingual tooth surfaces and (II) comparing plaque removal by three manual toothbrushes with different brushhead designs (convex, multilevel and flat trimmed) on lingual mandibular tooth surfaces. METHOD: In a clinical single-blind, crossover, 24-h plaque-regrowth study on 25 subjects, a computer-based index (PPI) was used to evaluate pre- and postbrushing plaque on lingual surfaces of mandibular premolars and molars. Subjects brushed their teeth under standardized conditions at three visits, each time with a different, randomly assigned toothbrush. RESULTS: The intraoral camera system allowed a reproducible and relatively convenient access to the lingual surfaces of the mandibular teeth and provided an increase in objectivity. Overall, each brush achieved statistically significant plaque removal, however, none reached clinical relevance. The multilevel brush was superior at specific sites, but failed to show statistically significant superiority in terms of overall plaque reduction. Without regard of the toothbrush used, the right handed subjects were less efficient in removing plaque from the right side compared to the left. CONCLUSIONS: The method is able to detect even small differences in plaque reduction. None of the different brushhead designs was able to compensate an insufficient brushing techniques.

Gliding capacity of different dental flosses.

BACKGROUND: One of the major concerns with the use of dental floss is the passage of the proximal contact, which might be influenced by the material characteristics of the floss. The aim of this study was to compare the gliding capacities of different flosses with major differences in structure and experimental behavior in vivo. METHODS: In a clinical, single-blind, crossover study of 27 subjects, the forces necessary for passing all 14 proximal contacts between the first premolars were measured using 2 polytetrafluoroethylene (PTFE)-based flosses, 2 nylon-based flosses, and 1 nylon-based tape. The flosses were fixed in a special holder with strain gauges, which allowed registration of the maximum forces at insertion into and removal from the interdental area. RESULTS: In most contacts, the PTFE flosses needed less force compared to the nylon flosses. The range between the flosses was higher in the mandible compared to the maxilla and increased from the mesially located contacts to the more distally located contacts. The nylon tape required higher forces at insertion for all maxillary contacts. All other flosses proved to be equivalent at these contacts. CONCLUSIONS: PTFE flosses are superior to nylon flosses in terms of passing stronger proximal contacts in both directions. Due to gliding differences between different types of floss, the selection of a floss has the potential of compensating intra- and interindividual variation in contact strengths.