Bernd Reitemeier

A prospective 10-year study of metal ceramic single crowns and fixed dental prosthesis retainers in private practice set tings

STATEMENT OF PROBLEMnMetal ceramic restorations are widely used in prosthodontics, but long-term data on their clinical performance in private practice settings based on prospective trials are sparse.nnnPURPOSEnThis clinical trial was designed to provide realistic long-term survival rates for different outcomes related to tooth loss, crown loss, and metal ceramic defect.nnnMATERIAL AND METHODSnNinety-five participants were provided with 190 noble metal ceramic single crowns and 138 participants with 276 fixed dental prosthesis retainer crowns on vital posterior teeth. Follow-up examinations were scheduled 2 weeks after insertion, annually up to 8 years, and after 10 years. Kaplan-Meier survival analyses, Mantel-Cox logrank tests, and Cox regression analyses were conducted.nnnRESULTSnBecause of variations in the time of the last examinations, the maximum observation period was 12.1 years. For the primary outcome loss of crown or tooth, the Kaplan-Meier survival rate was 94.3% ±1.8% (standard error) at 8.0 years (last outcome event) for single crowns and 94.4% ±1.5% at 11.0 years for fixed dental prosthesis retainer crowns. The difference between the survival functions was not significant (P>.05). For the secondary outcome metal ceramic defect, the survival rate was 88.8% ±3.2% at 11.0 years for single crowns and 81.7% ±3.5% at 11.0 years for fixed dental prosthesis retainer crowns. In Cox regression models, the only significant covariates for the outcome event metal ceramic defect were bruxism in the medical history (single crowns) and signs and symptoms of bruxism (fixed dental prosthesis retainer crowns) with hazard ratios of 3.065 (95% CI 1.063 - 8.832) and 2.554 (95% CI 1.307 - 4.992).nnnCONCLUSIONSnMetal ceramic crowns provided in private practice settings show good longevity. Bruxism appears to indicate a risk for metal ceramic defects.

Stability of fixation of diacapitular fractures of the mandibular condylar process by ultrasound-aided resorbable pins (SonicWeld Rx® System) in pigs

To assess the stability of osteosynthesis in diacapitular condylar fractures we compared fixation using ultrasound-aided resorbable pins with poly-(D,L)-lactide (SonicWeld® Rx, KLS Martin, Tuttlingen, Germany) with that of titanium screws in 20 pig mandibles, 10 in each group. Isolated diacapitular fractures were created using a surgical chisel. Ten fractures were each repositioned and fixed by two pins (17 and 11 mm long, 2.1mm in diameter), and 10 fractures were fixed by two titanium screws of equal length, 2.0mm in diameter. Shear tests were done immediately after treatment to measure the maximum force to disrupt the fixation. Fixation with pins resisted mean shear forces of 310N until the pins fractured, whereas fixation with titanium screws failed at 918N when the screws pulled out of the bone. Long-term stability and resorption of pins will have to be analysed in an in vivo study.

Analysis of Complications after Reconstruction of Bone Defects Involving Complete Mandibular Resection Using Finite Element Modelling

Background: In a retrospective study, risk factors for complications after the bridging of mandibular defects using reconstruction plates were reviewed. Especially the loosening of the plate-screw-mandible complex should be analyzed with a finite element model in order to reduce plate complications in future. Patients and Methods: We examined 60 patients who underwent a treatment with reconstruction plates after tumor resection during a period of 10 years. The problem of screw loosening was additionally reviewed by means of a finite element study, and a model for the loosening process was developed. Results: Our postoperative examination showed that 26 patients suffered from complications that required an early removal of the plate. These complications were oral or extraoral plate exposures, the looseness of screws with or without plate displacement, and plate fractures. Thereby, we noticed that maxillary and mandibular areas of opposing teeth, the size of the mandible defect, and the crossing of the orofacial midline are all risk factors for plate complications. On the basis of the finite element model, a modified arrangement of the screws was derived. Hence, a new type of resection plate was established. Conclusions: By repositioning the screw holes along the long axis of the plate, the transition from tensile force to torque force of the screws in the screw-plate-bone complex can be minimized. Thereby, the complication of screw loosening will be considerably reduced.

Bone block fixation by ultrasound activated resorbable pin osteosynthesis: a biomechanical in vitro analysis of stability.

OBJECTIVESnThe aim of this study was to determine the compound strength of the fixation between 2 blocks of synthetic bone using ultrasound activated resorbable pins (regarding drill hole diameter) and compare them to fixation with titanium miniscrews. Resorbable pins were up to 17 mm long.nnnSTUDY DESIGNnTwo synthetic bone blocks (Sawbone) were fixed by either a resorbable pin or miniscrew osteosynthesis. Maximum tensile forces were determined mechanically. Pin lengths of 7 mm, 11 mm, and 17 mm were analyzed in relation to different drill hole diameters.nnnRESULTSnThe ideal drill hole configuration was a combination of diameters of 2.1/1.6 mm (in a lag screw configuration). Mean maximum tensile force was 80 N for 7 mm pins (105 N/11 mm, 69 N/17 mm). In comparison, tensile forces of titanium screws were 20 N (7 mm), 97 N (11 mm), and 135 N (17 mm).nnnCONCLUSIONSnOsteosynthesis by resorbable pins reached equal compound strength levels compared with titanium miniscrews. This in vitro study was the basis for a clinical trial of ultrasound-guided resorbable pin osteosynthesis.

A pilot study of three methods for the reduction of bacterial contamination of dental unit water systems in routine use

Three different methods for minimizing the bacterial contamination of the water system in a SIRONA C2 type dental unit were investigated sequentially. Without any decontamination method, water from the hand piece, air-water-jet and mouthwash were continuously contaminated by 10(3) to 10(5) colony forming units (cfu) of aerobic mesophilic bacteria per milliliter. A reduction to below 100 cfu/ml was achieved by continuous adding of a chemical microbicide based on hydrogen peroxide and silver ions. However, this was only possible after rinsing the system thoroughly for at least two minutes after interruptions of the treatment. Long-lasting low counts of below 100/ml were obtained by means of an in-line bacteria filter, in connection with the provision of a thermo-chemical or thermal decontamination of the water pipes and hand pieces after the filter. The electrolyte release of chlorine from the dental unit tap water by anodic oxidation without addition of any chemical disinfectant also resulted in continuously low colony numbers of the water. In this case, regular decontamination of the end parts of the pipes and hand pieces was not necessary.

Experimental study on the behavior of primary human osteoblasts on laser-cused pure titanium surfaces

Mandibular tumor resection can lead to a mandibular segmental defect. LaserCUSING® is used to produce a mandibular implant, designed to be identical to the shape of the mandibular defect. Novel microrough surfaces result from this generative technology. In the current study, the behavior of human osteoblasts on untreated laser-cused titanium specimens or on specimens conditioned with different blasting agents was analyzed. The conditioning of these specimens resulted in surfaces with graded roughness. White light confocal microscopy and single-cell force spectroscopy were used to characterize the surface of the specimens and to quantify the initial adhesion of primary human osteoblasts to the specimens, respectively. Furthermore, cell growth, viability, apoptosis as well as mineralization of the specimens were analyzed over a time-period of 2 months. Compared to specimens that were treated with blasting agents, untreated specimens had the highest surface roughness. Quantitative SCFS measurements demonstrated that the adhesion of human primary osteoblasts was the highest on these specimens. Additionally, the untreated specimens allowed the highest number of osteoblasts to colonize. Mineralization studies showed increasing calcium and phosphor elemental composition for all specimen series. It can be concluded that untreated laser-cused titanium specimens are superior to promote the initial adhesion and subsequent colonization by osteoblast cells.

Clinical Test of Masticatory Efficacy in Patients with Maxillary/Mandibular Defects Due to Tumors

Background: The goal of the study was to evaluate the masticatory efficacy in patients who had been provided with resection prostheses after tumor removal in the maxillary/ mandibular region. These patients complained of impairment of masticatory function. Patients and Methods: 3 groups of patients were compared under clinical-experimental conditions. A uniform chewing material was masticated by the participants under standardized conditions. A sieving procedure was used to evaluate the masticatory efficacy. Analysis of the particle sizes and particle masses obtained was performed with the aid of computers. Results: The results showed that the masticatory efficacy of the patients with resection prostheses was the lowest of the 3 groups compared. The number of existing supporting zones and the location of the defect were found to be important influencing factors. Recording of the dietary habits of all patients was performed using a standardized dietary questionnaire. These data were analyzed using the corresponding software of the German Nutrition Society. With regard to the patients with resection prostheses, it was revealed that they often switched to food that did not require mastication. Conclusions: A nutritional guideline for patients with resection prostheses was developed, which is available for downloading free of charge on the Internet.

Planning implant positions for an auricular prosthesis with digital data

The esthetic result of an auricular prosthesis is influenced by the position of the prosthesis incorporating the implants. The entire surface of the patients head is captured by means of a conventional computed tomography (CT). The digital data are used to mirror the contralateral unimpaired ear for restoration of the impaired side. The virtual ear is integrated into a template covering the auricular defect and indexed to the nasal area with computer-aided technology (CAD/CAM). This virtual template is converted into an acrylic resin template. With that the surgeon and the anaplastologist should determine the optimal implant position of the auricular prosthesis.

Creation and utilization of a digital database for nasal prosthesis models.

Background: The study describes the development and implementation of a digital nose database in order to provide patients with nasal prostheses following rhinectomy. Mirrored data for computer-aided design (CAD) cannot be used due to the unpaired structure of the nose. Materials and Methods: The faces of 202 people were digitized using a 3-dimension (3D) scanner. The noses were scaled, measured and classified according to objective criteria. The physician, the patient and the anaplastologist can collaborate in order to select an appropriate nose from the multitude of existing nose types and sizes. Virtual ‘fittings’ and an individual adaptation of the nose are feasible. For this purpose the epiTecture software was applied. The selected nose is then created on a 3D printer as a thermopolymer model. This model can be fitted and corrected as a physical model on the patient. The remaining steps are identical to conventional prosthesis production. Results: A digital nose database was developed at the University Hospital Dresden with the help of the epiTecture software. Instructions for usage are illustrated using the example of a patient. Conclusions: The process of providing nasal prostheses described in this paper is different from conventional processes. This is primarily due to the elimination of physical modeling, causing substantially less strain for the patient.

arzneimitteltherapie und mundgesundheit bei pflegebedürftigen senioren in alten- und pflegeheimen

ZusammenfassungIm Rahmen einer Studie zur Mundgesundheit pflegebedürftiger Senioren (n=530) in Altenpflegeheimen wurde gleichzeitig die aktuelle Medikation erhoben. Von den zumeist multimorbiden Heimbewohnern werden eine Vielzahl von Medikamenten (z.B. Diuretika, b-Rezeptorenblocker, Psychopharmaka) mit der Möglichkeit eine Xerostomie hervorzurufen, eingenommen. Xerostomie stellt neben unzureichender Mundpflege einen Risikofaktor für die Zahn- und Mundgesundheit dar. Medikamente mit xerogenem Risiko erhielten zwei Drittel der Heimbewohner, in 134 Fällen fanden Mehrfachverordnungen statt. Diuretika stellten die umfangreichste Gruppe der verordneten Arzneimittel dar (36, 5%). Immerhin ein Drittel erhielten ein oder mehrere Psychopharmaka bzw. Hypnotika / Sedativa. Eigene Zähne hatten 37, 9% der Probanden (Mittelwert der Zahnzahl: 8, 1). Kronenkaries wurde bei 40% der Heimbewohner mit eigenen Zähnen festgestellt, Wurzelkaries bei 28%. Die Mundgesundheit, besonders die Zahnpflege der vorhandenen eigenen Zähne war unzureichend (OHI-Index Mittelwert 5, 7). Statistisch gesicherte Korrelationen zwischen den Medikamenten mit xerogenem Risiko und vorhandener Kronen- bzw. Wurzelkaries konnten nicht festgestellt werden. Signifikante Zusammenhänge zwischen Prothe-senstomatitis und verordneten Arzneimitteln sind nicht erkennbar. Es ist erforderlich, adäquate Konzepte zur Verbesserung der Pflegesituation zu entwickeln. Das Pflegepersonal muss auf dem Gebiet der Mundpflege geschult werden. Es ist ein Betreuungsnetzfür die älteren Menschen aus den betreuenden Ärzten, Zahnärzten und dem Pflegepersonal zu realisieren. Die aktuelle Medikation der Heimbewohner muss von allen genannten Berufsgruppen berücksichtigt werden.AbstractDuring a study on the oral health of senior citizens (n=530) who require nursing care and reside in nursing homes, their current medication was also assessed. Many of the mostly polypathic nursing home residents take numerous medications (exemplary diuretics, beta blockers, psychotropic drugs) which can cause xerostomia. In addition to inadequate oral hygiene, xerostomia is a risk factor for dental and oral health. Two thirds of the nursing home residents received medications carrying xerogenic risks; in 134 cases there were multiple prescriptions thereof Diuretics comprised the largest group of the prescribed drugs (36.5%). One third of the residents received one or more psychotropic drugs, hypnotics or sedatives. Of the test subjects, 37.9% had their own teeth (mean value of the teeth number: 8.1). Crown caries were noted in 40% of the nursing home residents who had their own teeth, and root caries were found in 28%. Their oral health status, particularly the dental care of their own existing teeth, was poor (OHI mean value: 5.7). Statistically proven correlations between the medications with xerogenic risks and existing crown or root caries were not found. The same situation appears with prosthesis stomatitis. Adequate concepts for the improvement of the nursing care situation must be developed. The nursing personnel must be trained in oral care. A care network consisting of the responsible physicians, dentists and nursing personnel must be created. The current medication of the nursing home residents must be taken into consideration by all of the above-named professional groups.