Evaluation of the dental curriculum at the University of Basel. Does the Master of Dental Medicine adequately prepare for the professional practice?

The present study reports the results of a structured survey of graduates intending to evaluate the education at the Dental School of the University of Basel in the years from 2006 to 2014. In addition, dentists and practice owners supervising graduates from Basel in daily clinical routine or hiring them as assistant dentists were questioned. The aims of the current survey were (1) to analyze own subjective experiences, (2) to assess potential differences between the cohorts prior to and after the implementation of the Bologna reform, (3) to compare the rating regarding theoretical knowledge and practical skills, and (4) to disclose potential for improvement. It was found that according to both their own assessment and the rating of the practice owners, graduates possess the basic dental expertise. The alumni rated their theoretical knowledge higher than their clinical practical skills and indicated a potential for intensification in the fields of dental surgery and implantology. When comparing the cohorts who had completed their studies according to the old (until 2010) and new study regulations, there were only minor differences; the own skills related to patient information about treatments were better rated by alumni who had been trained according to the new study regulations. The curriculum leading to the Master of Dental Medicine at the University of Basel fundamentally prepares graduates for the professional activity, but the additional acquisition of clinical experience in daily practice is indispensable.

Comparison of two test designs for evaluating the shear bond strength of resin composite cements

OBJECTIVE

To compare a shear bond strength test for resin composite cements developed in order to better consider the shrinkage stress (here termed "Swiss shear test") with the shear test design according to ISO 29022.

METHOD

Four restorative materials (VITA Enamic (VE), VITA Suprinity (VS), Vitablocs Mark II (VM) and VITA YZ T (YZ)) served as substrate. VE, VS and VM were polished or etched. YZ was polished, sandblasted or etched. Specimens were either bonded according to the Swiss or the ISO shear test. RelyX Unicem 2 Automix, Maxcem Elite and PermaFlo DC were used as cements. Shear bond strength (SBS) was measured. Failure modes (adhesive, cohesive or mixed) were evaluated by means of SEM.

RESULTS

Mean SBS values obtained with the Swiss shear test were significantly lower than those obtained with the ISO shear test. VE and VM exhibited similar SBS, values of VS were significantly higher. On etched surfaces VM and VE exhibited primarily cohesive failures, VS primarily adhesive failures. On polished substrates significantly lower bond strength values and exclusively adhesive failures were observed. YZ exhibited solely adhesive failures. Compared to polished YZ, SBS significantly increased after sandblasting and even more after etching. Only for adhesively failed specimens mean SBS values of Swiss and ISO shear test were strongly correlated.

SIGNIFICANCE

Both test designs showed the same ranking of test results. When adhesive failure occurred test results were strongly correlated. When cohesive failure was involved, both test designs did not provide reliable results.

Influence of the bleaching interval on the luminosity of long-term discolored enamel-dentin discs

OBJECTIVES

The aim of this study is to investigate the influence of changing the sodium perborate-tetrahydrate (PBS-4) at a 4-day interval versus no change after 16 days of internal bleaching.

MATERIALS AND METHODS

Two hundred and ten bovine enamel-dentin discs were discolored for 3.5 years with 14 different endodontic materials. All groups with a discoloring index of ∆E (mean) ≥ 5.5 were included in the present investigation: ApexCal (APCA), MTA white + blood (WMTA+BL), Portland cement + blood (PC+BL), blood (BL), MTA gray (GMTA), MTA gray + blood (GMTA+BL), Ledermix (LED), and triple antibiotic paste containing minocycline (3Mix). Fourteen specimens of each group were randomly assigned into two treatment groups: (1) no change of the PBS-4 (n = 7); (2) change of the PBS-4 every 4 days (n = 7). Color measurements were taken at 10 different time intervals and the L*a*b* values were recorded with a spectrophotometer (VITA Easyshade® compact).

RESULTS

In the group 3Mix, significantly better results were achieved by changing the bleaching agent every 4 days (P = 0.0049; q = 0.04), while the group WMTA+BL indicated better results by no change of the bleaching agent (P = 0.0222, q = 0.09). All remaining groups showed no statistical difference between the two treatment procedures.

CONCLUSIONS

Moderate discolorations can be successfully treated without changing the bleaching agent over a period of 16 days. Changing the sodium perborate-tetrahydrate every 4 days is preferred in case of severe discolored enamel-dentin discs only.

CLINICAL RELEVANCE

This approach may offer a reduced number of clinical appointments and a secondary cost reduction to the patient.

Non-surgical periodontal therapy supplemented with systemically administered azithromycin: a systematic review of RCTs

BACKGROUND

Azithromycin may be an alternative adjunctive systemic antibiotic in non-surgical periodontal therapy.

OBJECTIVE

This study aims to identify randomized controlled trials evaluating non-surgical periodontal treatment of chronic and/or aggressive periodontitis supplemented with systemically administered azithromycin.

MATERIALS AND METHODS

A systematic literature search was performed for publications published by 31 March 2014 using electronic databases and hand search. Randomized controlled trials published in English or German language, with a follow-up ≥6 months were included. From 231 titles identified, nine publications were eligible for inclusion.

RESULTS

Among the studies included, showing some risk of bias, seven reported on patients with chronic periodontitis and two with aggressive periodontitis. Minor adverse events were described in five studies. A synthesis of results using a vote counting method was applied. Significant (p < 0.05) beneficial effects of azithromycin were shown in six studies for probing depth changes and in five studies for clinical attachment level changes.

CONCLUSION

In contrast to aggressive periodontitis patients, data from this analysis indicate a potential benefit of systemic azithromycin as adjunctive to non-surgical periodontal therapy in chronic periodontitis patients.

CLINICAL RELEVANCE

When contraindications for the standard antibiotics are present, azithromycin (AZM) may be considered as alternative systemically administered antibiotic drug in selected cases of chronic periodontitis.

Influence of time, toothpaste and saliva in the retention of Streptococcus mutans and Streptococcus sanguinis on different toothbrushes

OBJECTIVES

The intraoral transmission of cariogenic and periodontopathogenic species seems to be facilitated by contaminated toothbrushes and other oral hygiene devices. The aim of this investigation was to analyze the in vitro retention and survival rate of Streptococcus mutans and Streptococcus sanguinis on different toothbrushes. The impacts of human saliva and antimicrobial toothpaste on these parameters were further evaluated.

MATERIAL AND METHODS

Part I: Four toothbrushes (Colgate 360°, Curaprox CS5460 ultra soft, elmex InterX, Trisa Flexible Head3) were contaminated by S. mutans DSM 20523 or S. sanguinis DSM 20068 suspensions for three minutes. Bacteria were removed from the toothbrushes after either three minutes (T0) or 24 hours (T24) of dry storage and grown on Columbia blood agar plates for the quantification of colony-forming units (CFUs). Part II: The effects of saliva from a caries-active or a caries-inactive person and of toothpaste containing 0.12% chlorhexidine digluconate were also tested.

RESULTS

Part I: After three minutes of dry storage, approximately one percent of the bacteria were still detectable on the toothbrushes. After 24 hours, S. sanguinis exhibited a more pronounced decrease in viable cell numbers compared with S. mutans but the differences were not significant (Kruskal-Wallis test, p>0.05). Part II: The addition of human saliva from a caries-active or caries-inactive person slightly increased the retention of both streptococcal species at T0. The use of toothpaste had no influence on the amount of viable streptococci at T0, but it reduced the microbial load after 24 hours of storage. There were only slight nonsignificant differences (p>0.05) between the four toothbrushes.

CONCLUSIONS

In vitro bacterial retention and survival of S. sanguinis and S. mutans on different toothbrushes occurred. Within the limitations of this study, the use of human saliva or an antimicrobial toothpaste did not lead to significant differences in the microbial load on toothbrushes.

Influence of proximal box elevation on the marginal quality and fracture behavior of root-filled molars restored with CAD/CAM ceramic or composite onlays

OBJECTIVES

This study investigated the influence of proximal box elevation (PBE) with composite resin when applied to deep proximal defects in root-filled molars with mesio-occluso-distal (MOD) cavities, which were subsequently restored with computer-aided designed/computer-aided manufacturing (CAD/CAM) ceramic or composite restorations.

MATERIALS AND METHOD

Root canal treatment was performed on 48 human mandibular molars. Standardized MOD cavities were prepared with the distal box located 2 mm below the cemento-enamel junction (CEJ). The teeth were randomly assigned to one of four experimental groups (n = 12). In groups G1 and G2, the distal proximal box was elevated up to the level of the CEJ with composite resin (PBE). No elevation was performed in the remaining two groups (G3, G4). CAD/CAM restorations were fabricated with feldspathic ceramic (Vita Mark II, CER) in groups G1 (PBE-CER) and G3 (CER) or with resin nano-ceramic blocks (Lava Ultimate, LAV) in groups G2 (PBE-LAV) and G4 (LAV). Replicas were taken before and after thermomechanical loading (TML; 1.2 Mio cycles; 49 N; 3,000 thermocycles between 50 °C and 5 °C). Following TML, load was applied until failure. Fracture analysis was performed under a stereomicroscope (×16). Marginal quality before and after TML (tooth restoration, composite restoration) was evaluated using scanning electron microscopy (×200).

RESULTS

After TML, lower percentages of continuous margins were observed in groups G1-G3 compared with pre-TML assessments; however, the differences were not statistically significant. For group G4-LAV, the marginal quality after TML was significantly better than in any other group. The highest mean fracture value was recorded for group G4. No significant difference was found for this value between the groups with PBE compared with the groups without PBE, regardless of the material used. The specimens restored with ceramic onlays exhibited fractures that were mainly restricted to the restoration while, in teeth restored with composite onlays, the percentage of catastrophic failures (fractures beyond bone level) was increased.

CONCLUSION

PBE had no impact on either the marginal integrity or the fracture behavior of root canal-treated mandibular molars restored with feldspathic ceramic onlays. CAD/CAM-fabricated composite onlays were more favorable than ceramic onlays in terms of both marginal quality and fracture resistance, particularly in specimens without PBE.

CLINICAL RELEVANCE

Composite onlays with or without PBE may be a viable approach for the restoration of root-filled molars with subgingival MOD cavities.

Associations of HLA-A, -B and -DRB1 types with oral diseases in Swiss adults

Human leukocyte antigens (HLA) are crucial components of host defense against microbial challenge but the associations of HLA types with oral infectious diseases have not been studied in detail. This prospective cross-sectional study examined associations of HLA-A, -B and -DRB1 types with common oral diseases in a healthy Swiss adult population. 257 subjects (107 m, 150 f, mean age: 43.5 yr; range: 21-58 yr) with known HLA-A, -B and -DRB1 profiles and comprehensive medical records were included. A thorough anamnesis was followed by oral examinations including saliva flow measurements, the DMFT score for cariological status, complete periodontal status with plaque and bleeding indexes as well as assessment of mucosal alterations and temporomandibular dysfunction (TMD). Student's t-test and Pearson chi-square test were utilized to compare the oral diseases between HLA positive and negative subjects. Bonferroni correction for multiple comparisons was used and PBonf<0.05 was considered statistically significant. HLA types -B15 (PBonf = 0.002), -B51 (PBonf = 0.02) and -DRB1*12 (PBonf = 0.02) were associated with less periodontal disease manifestations. HLA-A32 had a positive association with TMD dysfunction (PBonf = 0.012). No other statistically significant associations were observed. In conclusion, HLA types may contribute to the development of oral diseases in generally healthy Caucasian adults.

Combinatorial effects of amoxicillin and metronidazole on selected periodontal bacteria and whole plaque samples

OBJECTIVE

The aim of the present study was to analyze in vitro the combinatorial effects of the antibiotic combination of amoxicillin plus metronidazole on subgingival bacterial isolates.

DESIGN

Aggregatibacter (Actinobacillus) actinomycetemcomitans, Prevotella intermedia/nigrescens, Fusobacterium nucleatum and Eikenella corrodens from our strain collection and subgingival bacteria isolated from patients with periodontitis were tested for their susceptibility to amoxicillin and metronidazole using the Etest. The fractional inhibitory concentration index (FICI), which is commonly used to describe drug interactions, was calculated.

RESULTS

Synergy, i.e. FICI values ≤ 0.5, between amoxicillin and metronidazole was shown for two A. actinomycetemcomitans (FICI: 0.3), two F. nucleatum (FICI: 0.3 and 0.5, respectively) and one E. corrodens (FICI: 0.4) isolates. Indifference, i.e. FIC indices of >0.5 but ≤4, occurred for other isolates and the 14 P. intermedia/nigrescens strains tested. Microorganisms resistant to either amoxicillin or metronidazole were detected in all samples by Etest.

CONCLUSION

Combinatorial effects occur between amoxicillin and metronidazole on some strains of A. actinomycetemcomitans, F. nucleatum and E. corrodens. Synergy was shown for a few strains only.

Cost-effectiveness of anterior implants versus fixed dental prostheses

For the restoration of an anterior missing tooth, implant-supported single crowns (ISCs) or fixed dental prostheses (FDPs) are indicated, but it is not clear which type of restoration is more cost-effective. A self-selected trial was performed with 15 patients with ISCs and 11 with FDPs. Patient preferences were recorded with visual analog scales before treatment, 1 month following restoration, and then annually. Quality-adjusted tooth years (QATYs) were estimated by considering the type of reconstruction for replacing the missing tooth and its effect on the adjacent teeth. A stochastic cost-effectiveness model was developed using Monte Carlo simulation. The expected costs and QATYs were summarized in cost-effectiveness acceptability curves. ISC was the dominant strategy, with a QATY increase of 0.01 over 3 years and 0.04 over 10 years with a higher probability of being cost-effective. While both treatment options provided satisfactory long-term results from the patient's perspective, the lower initial costs, particularly laboratory fees, were responsible for the dominance of ISCs over FDPs.

Is furcation involvement in maxillary molars a predictor for subsequent bone augmentation prior to implant placement? A pilot study

AIM

The aim of this pilot study was to analyze the interfurcal bone height in relation to the possible need for subsequent sinus floor elevation in patients with advanced periodontitis and furcation involvement of first and/or second maxillary molars.

MATERIAL AND METHODS

Seventeen dentate patients, who received cone beam computed tomography (CBCT) for detailed preoperative diagnosis and planning of surgical interventions at periodontally involved maxillary molars (17 first and 15 second molars), were consecutively recruited for the study. The minimal bone height in the interfurcal region was measured from CBCT and related to furcation involvement, residual bone above the root tips, and the clinical probing pocket depth (PPD).

RESULTS

The minimal interfurcal bone height measured 4.1 ± 2.6 mm on average with 75% of maxillary molars having ≤ 6 mm and almost 60% having only ≤ 4 mm bone height left below the sinus floor. A higher risk for reduced interfurcal bone height of ≤ 4 mm was given when residual PPD of ≥ 6 mm was remaining at two or more tooth sites (OR 0.10; 0.11).

CONCLUSIONS

The majority of periodontally involved maxillary molars had a substantially reduced interfurcal bone height, particularly with at least two sites with residual PPD ≥ 6 mm. This was a predictor for a subsequent need for sinus floor elevation when tooth replacement with a dental implant is desired.

Is the Schneiderian membrane thickness affected by periodontal disease? A cone beam computed tomography-based extended case series

OBJECTIVE

The aim was to assess the thickness of Schneiderian membranes (SM) in patients with advanced periodontal disease.

METHODS

17 dentate patients (DG) scheduled for periodontal surgery on maxillary molars were consecutively recruited and cone beam computed tomographies performed for preoperative diagnosis. Twenty-one patients (EG) requiring cone beam computed tomography-based planning of implant placement in the edentulous posterior maxilla served as controls.

RESULTS

Schneiderian membrane thickness measured from cone beam computed tomography was significantly greater in the dentate group compared to the edentulous group, both in the first (p = 0.028) and second (p < 0.001) molar position. In the dentate group, clinical signs of periodontal destruction (increased probing pocket depth or furcation involvement) were not associated with Schneiderian membrane thickness. Additional findings, such as periapical lesions (p = 0.008), and the distance between root tips and maxillary sinus revealed a significant association (p = 0.036) with Schneiderian membrane thickness.

CONCLUSION

In molar regions with periodontal destruction, Schneiderian membrane thickening occurred, particularly in combination with small bone layers above the root tips or periapical lesions.

Treatment of periodontitis as a manifestation of neutropenia with or without systemic antibiotics: a systematic review

The purposes of this paper were to systematically review the clinical presentations and management of periodontitis patients with neutropenia and present a patient with severe autoimmune neutropenia. Twenty-four case reports describing a total of 33 patients were identified. The reported signs and symptoms occurred in either a generalized or localized pattern. Improvements in periodontal condition were observed in 86% of patients who were administered adjuvant systemic antibiotics compared to 47% of patients who were not given supplemental therapy. Granulocyte-colony stimulating factor was administered to 67% of the neutropenic patients, and both improvement and progression of the hematological condition were monitored. Scaling and root planing, in combination with systemic antibiotics to supplement therapy for the underlying disease, have been successful in most cases.