[German dental and postgraduate education in the European context]. / Zahnärztliche Aus- und Weiterbildung im europäischen Kontext.

The dental curriculum in Germany is still based on a concept from 1955 with some revisions in certain aspects. All groups involved are interested in a new and more current version. In doing this, the compatibility with European concepts should be a main goal. The Association for Dental Education in Europe (ADEE), to which about 160 of the 200 European dental education associations are members, is in charge of coordinating projects to create a network of European universities, which intends to harmonize higher education in Europe and to create a core curriculum for the dentistry program. Based on a visitation and evaluation program at more than 50 oral and maxillofacial surgery centers, a paper for the profiles and competencies for future European dentists was formulated for the creation of a modular curriculum, for the integration of the ECT (European Credit Transfer) system, and for quality assurance of the dentistry curriculum. Especially for the situation in Germany, consequences must be drawn for further dentistry and postgraduate educational concepts, which are not completely identical with the ADEE concepts, but which can use elements of the basic Bologna concepts.

The repair of direct composite restorations: an international survey of the teaching of operative techniques and materials.

This article reports the findings of a study on the aspects of the teaching of repair as a conservative alternative to the replacement of failing direct composite restorations (DCRs) in primary dental degree curricula in the UK and Ireland, Germany and Scandinavia. Data on teaching, including operative techniques applied in the repair of DCRs, were collected by means of a questionnaire sent to 58 dental schools in the surveyed countries. Based on the overall response rate of 83%, the findings indicate that the majority (59%) of the schools in the countries surveyed may be found to teach the repair of DCRs. However, marked variations were observed in respect of this teaching and the expected longevity of repaired DCRs. Where the repair of DCRs was not taught, views differed as to the intentions, if any, to include this teaching in the curriculum. It is concluded that the teaching of DCRs may be found to be widespread in dental schools in the UK and Ireland, Germany and Scandinavia, with this teaching being subjected to considerable variation within and between countries.

Removal of amalgam, glass-ionomer cement and compomer restorations: changes in cavity dimensions and duration of the procedure.

This study investigated changes in the dimensions of Class II cavities following the removal of amalgam, glass ionomer and compomer restorations. In 30 extracted caries-free human molars, preparation for 60 mesio-occlusal and occluso-distal cavities (two cavities per tooth) occurred. With a CEREC 3 laser triangulation sensor and software-based construction analysis, the dimensions of the cavities at seven defined sites were measured. The cavities were randomized into four groups. Group 1 was restored with Ketac-Fil glass-ionomer cement, Group 2 with amalgam and Group 3 with Compoglass F compomer. In Group 4, Compoglass F was used in combination with photochromic Tetric Flow Chroma as a cavity liner. The completed restorations were then removed using 2x magnification and the cavities were once again controlled using the laser system. The duration of the removal procedure was also recorded. Changes in cavity dimensions (depth, height and width) following removal of the restorations were significantly smaller in Groups 1 and 2. Groups 3 and 4 were characterized by a significant overextension of the cavities compared to Groups 1 and 2 in all three dimensions. Group 4, with Tetric Flow Chroma as a cavity liner, showed better results than Group 3, but this improvement was not statistically significant. The duration of the removal procedure was significantly shorter in Group 2 than in the other groups.

Hemisection for treatment of an advanced endodontic-periodontal lesion: a case report.

AIM: To emphasize the importance of primary endodontic treatment when dealing with endo-perio lesions and to demonstrate the considerable healing potential of the endodontic aspect. CASE REPORT: After several years of unsuccessful symptomatic periodontal treatment, an advanced endo-perio lesion on a right-mandibular first molar was successfully treated by root-canal treatment and hemisection after the re-evaluation of the lesion. This successful treatment appeared to have a positive effect on the patient's general well-being. KEY LEARNING POINTS: The origin of a combined endo-perio lesion is indicated by its clinical and radiographic appearance. The periodontal situation is often misinterpreted. The prognosis for the endodontic element of treatment is excellent. Local pathologic processes in the oral cavity may affect a patient's general health.

Cluster of Mycobacterium chelonae keratitis cases following laser in-situ keratomileusis.

PURPOSE: To describe a cluster of Mycobacterium chelonae keratitis cases involving patients who underwent laser in-situ keratomileusis (LASIK) at a single refractive surgery center. DESIGN: Descriptive case series of four patients and cohort study to identify disease associations. METHODS: Examination schedules, diagnostic tests, and therapy were based on best medical judgment. Isolates from three patients were compared by pulsed-field gel electrophoresis. Epidemiologic studies were performed to identify the source of infection. RESULTS: Seven of eight eyes developed M. chelonae keratitis following bilateral simultaneous LASIK. Each patient was thought to have diffuse lamellar keratitis initially, but all seven eyes were noted to have opacities suggestive of infectious keratitis by 13 to 21 days after surgery. All eyes had undergone hyperopic LASIK over four days in April 2001 by one surgeon in a community-based refractive surgery center. A cohort study of all patients undergoing LASIK at the same center in April 2001 revealed that M. chelonae keratitis occurred only in persons undergoing correction of hyperopia (seven of 14 eyes vs. none of 217 eyes undergoing myopic LASIK, P <.001). The only difference identified between procedures was use of masks created from a soft contact lens in hyperopic LASIK. Three isolates (three patients) were indistinguishable by pulsed-field gel electrophoresis. Eyes were treated with a combination of antimicrobial agents, including topical azithromycin in three patients, with resolution of infection in all eyes over 6 to 14 weeks. The source of infection was not identified on environmental cultures. CONCLUSION: Postoperative nontuberculous mycobacterial keratitis can occur in an epidemic fashion following LASIK. Topical amikacin, azithromycin, clarithromycin, ciprofloxacin, or a combination of these agents, appears to be effective treatment for these infections.

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.

Preparation of severely curved simulated root canals using engine-driven rotary and conventional hand instruments.

This in vitro study evaluated the efficacy and safety of six different nickel-titanium engine-driven instruments used with a torque-controlled engine device and nickel-titanium hand and stainless steel hand instruments in preparation of curved canals. A total of 80 curved (36 degrees) simulated root canals were prepared. Images before and after were superimposed, and instrumentation areas were observed. Time of instrumentation, instrument failure, change in working length and weight loss were also recorded. Results show that stainless steel hand instruments cause significantly less transportation towards the inner wall of the canal than do nickel-titanium hand instruments. No instrument fracture occurred with hand instruments, but 30-60% breakage of instruments was recorded during instrumentation with the engine-driven devices. The working length was maintained by all types of instruments. Newly developed nickel-titanium rotary files were not able to prevent straightening of the severely curved canals when a torque-controlled engine-driven device was used.

Comparative study of composite resin placement: centripetal buildup versus incremental technique.

An in vitro study was performed to evaluate the effect of two different proximal restoration techniques with different matrix systems on the marginal seal and microhardness of Class II composite restorations. Results indicated that the lowest, however, not significantly different, microleakage was achieved in totally bonded deep Class II restorations prepared with margins surrounded by enamel when using transparent matrices and reflective wedges in combination with the centripetal buildup technique. Highest surface hardness of composite resin was related to transparent matrices and reflecting wedges.

In vitro dentinal surface reaction of 9.5% buffered hydrofluoric acid in repair of ceramic restorations: a scanning electron microscopic investigation.

STATEMENT OF PROBLEM: Fracture of porcelain is a relatively common clinical misfortune. Recent research has indicated that strong bonds can be formed between composite and dental porcelain. Porcelain surfaces are etched with hydrofluoric acid and treated with silane coupling agents before composite application. The question is how exposed dentin may react to etching with hydrofluoric acid. PURPOSE: This investigation examined the effect of 9.5% buffered hydrofluoric acid, of 36% o-phosphoric acid alone and in combination on the surface structure of cut human dentin. MATERIAL AND METHODS: Human molar teeth were sectioned in approximately 0.8-mm thick slices and treated with different acids or their combinations. Application periods were 10, 60, and 180 seconds. Specimens were processed for SEM and for energy-dispersive x-ray (EDX) microanalysis. RESULTS: The smear layer on the surface of sectioned dentin was not completely removed by hydrofluoric acid alone and that a dense amorphous precipitate was formed on the peritubular zone. Starlike structures in dentinal tubules were visible. EDX analysis revealed different fluoride content on the treated surface, dependent on the etchant used. CONCLUSION: Topical application of hydrofluoric acid appeared to provide a dentinal surface with an amorphous precipitate of fluoride. This layer may be important both for resistance of dental caries in dentin and for bonding reactions.

Infectious keratitis after photorefractive keratectomy in a comanaged setting.

A 48-year-old man had simultaneous bilateral photorefractive keratectomy (PRK). The surgeon who performed the PRK did not see the patient in follow-up, and there was confusion regarding the comanaging doctor. Therefore, the patient was not examined immediately postoperatively. Several days later, he was hospitalized for an unrelated, painful orthopedic problem and heavily sedated. Seven days after the PRK, an ophthalmologist was consulted for ocular irritation and discharge. Examination showed bilateral, purulent conjunctivitis and severe infectious keratitis in the left eye. The patient was treated with periocular and topical antibiotics. Corneal cultures yielded Staphylococcus aureus. The keratitis resolved slowly, leaving the patient with hand motion visual acuity. A corneal transplant and cataract extraction was performed 15 months later, resulting in a best corrected visual acuity of 20/400 because of glaucomatous optic nerve damage. Severe infectious keratitis may occur after PRK. Poor communication between the surgeon, comanaging doctor, and patient may result in treatment delay.

Early- versus late-onset infectious keratitis after radial and astigmatic keratotomy: clinical spectrum in a referral practice.

PURPOSE: To compare the clinical characteristics of early- versus late-onset keratitis after radial keratotomy (RK) and astigmatic keratotomy (AK). SETTING: Referral subspecialty practice. METHODS: This retrospective review comprised 19 patients with infectious keratitis after RK and AK. Early- versus late-onset groups were analyzed for predisposing conditions; infiltrate location, size, and depth; microbiologic data; and final visual outcome. RESULTS: Ten patients in the early-onset group developed keratitis within a mean of 7.4 days after surgery (range 3 to 14 days). Nine patients in the late-onset group developed keratitis a mean of 5.4 years after surgery (range 1.5 to 15.0 years). Staphylococcus aureus was the predominant organism in the early-onset group and Pseudomonas aeruginosa in the late-onset group. In the early-onset group, most infiltrates occurred in the paracentral aspect of the RK incision and extended to the middle or posterior stroma. In the late-onset group, most infiltrates occurred in the peripheral portion of the RK incision and were localized to the superficial stroma. A hypopyon was present in 7 of 10 ulcers in the early group and in 1 of 9 in the late group. Two patients in the early group developed endophthalmitis. Most patients in the late-onset group had incisional pseudocysts; 2 had other risk factors for keratitis. Final visual acuity was 20/40 or better in 7 of 10 patients in the early group and in 8 of 9 patients in the late group. CONCLUSIONS: Early-onset corneal ulcers after incisional refractive keratotomy were usually paracentral and deep, whereas late-onset ulcers were usually peripheral and superficial. Despite the predominance of Staphylococcus and Pseudomonas in the early- and late-onset groups, respectively, a variety of organisms may be responsible for infections in keratotomy incisions.

Tooth-colored restorations of posterior teeth in German dental education.

Optimizing the quality of tooth-colored restorations is one of the main topics of current research. But there is only little information available about university education in this field. The aim of this study was to collect and evaluate data about the different aspects of dental education in Germany concerning tooth-colored restorations. Based on the response to a questionnaire from 90% of all German dental schools in the fall of 1997 a detailed survey is given of the utilization, indications, practical procedure, problems and limitations of both direct and indirect tooth-colored restorations done by students. The results indicate a wide-spread use of directly inserted composite for posterior teeth in the different education programs. Indeed, the preferred preparation of the cavity margin differs from school to school. Rebuilding an adequate proximal contact and a precise fit at the gingival margin are looked upon as the main problems of class II composite fillings. Ceramic inlays are mainly inserted by students in advanced clinical courses with the insertion procedure being claimed as the main problem of this technique. The findings of this study mostly show the same limitations and difficulties of tooth-colored restorations in education as found by research. Partly different teaching concepts are reflected in the differing scientific results.

Erbium:YAG laser application in caries therapy. Evaluation of patient perception and acceptance.

OBJECTIVES: In previous studies it has been demonstrated that the Er:YAG laser can be used to prepare cavities efficiently and without thermal damage to the adjacent dental hard and soft tissues. To investigate the patients' response to Er:YAG laser preparation of teeth, a prospective clinical study was performed in five dental hospitals. METHODS: To evaluate patients' perception and response to cavity preparation a direct comparison was made between conventional mechanical preparation and Er:YAG laser preparation of caries in dental hard tissues. Half of the preparations were completed by the laser alone with standardized parameters, with the other half being mechanically prepared. The sequential order of treatment was randomized, and clinical parameters such as depth and location of the cavities were carefully balanced. A three-score evaluation scheme of patient responses was used: comfortable, uncomfortable, very uncomfortable. In addition the patients were asked to decide which was the more uncomfortable form of treatment and the preferred treatment for future caries therapy. RESULTS: The study included 103 patients with 206 preparations distributed amongst 194 teeth. All teeth gave vital responses (ice test) before and after both types of treatment. The laser treatment was found to be more comfortable than the mechanical treatment, with high statistical significance. During treatment, the need for local anaesthesia was 11% for mechanical preparation compared to 6% during laser application. It was found that 80% of the patients rated the conventional preparation as more uncomfortable than the laser treatment and 82% of the patients indicated that they would prefer the Er:YAG laser preparation for further caries treatment. CONCLUSIONS: The application of the Er:YAG laser system is a more comfortable alternative or adjunctive method to conventional mechanical cavity preparation.

Endophthalmitis after radial keratotomy enhancement.

A 45-year-old man developed endophthalmitis after a radial keratotomy (RK) enhancement. He developed severe intraocular inflammation, hypopyon, and dense vitreous membranes 4 days after the enhancement surgery. Cultures of the corneal wound yielded a heavy growth of Streptococcus viridans. The inflammation subsided after treatment with intraocular, intravenous, and topical antibiotics. The patient subsequently developed a cataract and retinal detachment. This case demonstrates the risk of endophthalmitis after RK enhancement.

Aspergillus keratitis after radial keratotomy.

PURPOSE/METHODS: A case of severe Aspergillus keratitis after radial keratotomy manifested as a discrete midstromal infiltrate along a radial incision. Despite aggressive treatment with topical amphotericin B and oral itraconazole, the patient required a therapeutic penetrating keratoplasty. RESULTS/CONCLUSIONS: Histopathologic examination disclosed a corneal ulcer with numerous septate, branching hyphae throughout the stroma, and marked stromal necrosis. Aspergillus species should be included among the microbial pathogens responsible for infectious keratitis after radial keratotomy. If infectious keratitis is suspected, comprehensive cultures for bacteria and fungi should be obtained.