Clinical performance of occlusal onlays made of lithium disilicate ceramic in patients with severe tooth wear up to 11 years.

OBJECTIVES: Evaluation of survival and complication rate of monolithic occlusal onlays made of lithium disilicate ceramic used in patients with severe tooth wear up to 11years of clinical service. METHODS: In a prospective non-randomized clinical study 7 patients (4 male, 3 female; median age: 44.3±6.56years old) were restored full mouth with a total of 103 adhesively bonded occlusal onlays made of lithium disilicate ceramic (IPS e.max Press, Ivoclar Vivadent, Schaan, Liechtenstein). All restorations were examined during annual recall visits using periodontal parameters according to the modified United States Public Health Service (USPHS) criteria: (a) marginal discoloration, (b) secondary caries, (c) marginal integrity, (d) surface texture, (e) restoration fracture, and (f) occlusal wear, rating with Alpha, Bravo and Charlie over an observation period up to 11years (68-139 months; median: 94.9±26.1 months). Data was statistically analyzed using the Kaplan-Meier estimation. RESULTS: Monolithic lithium disilicate occlusal onlays presented a 100% survival rate. Four restorations within one patient (3.9%) presented marginal discoloration, one after 60 and three after 108 months (all rated Bravo). One restoration (1%) showed a marginal crack formation (technical complication) after 120 months, rated Bravo. No biological complication, debonding or secondary caries could be found and tested periodontal parameters showed excellent results. SIGNIFICANCE: Based on the analyzed data up to 11years, monolithic occlusal onlays made of lithium disilicate ceramic can be considered as a reliable treatment option for full-mouth rehabilitations in patients with severe tooth wear.

Digital implant planning and guided implant surgery - workflow and reliability.

Modern oral implantology and implant prosthetics depend on comprehensive diagnostics and precise planning to ensure the desired outcome and meet the patient's and the dentist's expectations. In this context, digital implant planning and guided implant surgery based on three-dimensional radiographic data and the digitised intraoral surfaces can be of excellent service. They provide valuable information and permit stringent backward planning to optimise the implantological and prosthetic result, improving the safety and efficiency of the surgical procedure and rendering the restorative outcome more predictable in terms of function, biology and aesthetics. However, template-guided implant surgery carries its own specific risks in terms of manufacturing inaccuracies and application errors. These possible sources of error must be recognised and carefully considered in order to avoid adverse consequences.

Oral health-related impact profile in full-mouth restored patients with two different tooth-colored restoration materials.

OBJECTIVES: To analyze the change of oral health impact profile (OHIP) in patients with full-mouth rehabilitations due to moderate/severe tooth wear dependent on different restorative materials (ceramic/experimental CAD/CAM composite). MATERIALS AND METHODS: Twenty-nine healthy patients (15 male/14 female, age 44.6 ± 28.4 years) requiring full-mouth rehabilitation due to different degrees of tooth wear were instructed to fill the German version OHIP-G49 questionnaire before (baseline) and 30 days after prosthetic treatment with ceramic (n = 17) or experimental CAD/CAM composite (n = 12) restorations. Questions were divided into five dimensions: appearance, oral functions, psychosocial impact, linguistic limitations, and orofacial pain; changes between both OHIP-questionnaires for each question and patient were dissected by difference values, separately. Data were analyzed with the Kolmogorov-Smirnov, Wilcoxon's signed-rank, Kruskal-Wallis, Mann-Whitney, and Cronbach's alpha tests (significance level p = 0.01). RESULTS: The appearance dimension showed the highest results (p < 0.001, 100% improvement with all values > 0); the linguistic limitations dimension presented the lowest improvement (p < 0.001). The other three dimensions were not statistically different. No statistical differences between the two materials depending on OHIP questionnaire results occurred. CONCLUSIONS: The esthetic appearance of the patients was influenced positively by full-mouth rehabilitation, irrespective of the material used. Improvements were also made in the parameters "toothache" and "problem of food intake." No statements could be made for the parameter "language." CLINICAL RELEVANCE: With an increasing number of patients with moderate/severe tooth wear, thorough knowledge about the improvement of OHIP is important. This information is advantageous for the consultation and handling of patients when complex treatments are planned.

Histo-anatomic 3D printing of dental structures.

The creation of dental restorations with natural appearance and biomechanics represents a major challenge for the restorative team. The manufacturing-process of high-aesthetic restorations from tooth-coloured restorative materials is currently dominated by manual manufacturing procedures and the outcome is highly dependent on the knowledge and skills of the performing dental technician. On the other hand, due to the simplicity of the manufacturing process, CAD/CAM restorations from different material classes gain more and more acceptance in the daily routine. Multi-layered restorations show significant aesthetic advantages versus monolithic ones, but are difficult to fabricate using digital technologies. The key element for the successful automated digital fabrication of aesthetic anterior restorations seems to be the form of the individual dentine core as defined by dentine enamel junction (DEJ) covered by a more transparent layer of material imitating the enamel layer to create the outer enamel surface (OES). This article describes the possibilities and technologies available for so-called '4D-printing'. It introduces the digital manufacturing process of multilayered anterior teeth using 3D multipart printing, taking the example of manufacturing replicas of extracted intact natural teeth.

CAD/CAM Polymer vs Direct Composite Resin Core Buildups for Endodontically Treated Molars Without Ferrule.

OBJECTIVES: The aim of this study was to investigate the restoration of broken-down endodontically treated molars without ferrule effect using glass ceramic crowns on different composite resin core buildups. METHODS AND MATERIALS: Forty-five decoronated endodontically treated teeth (no ferrule) were restored with a semidirect buildup using an experimental computer-aided design/computer-aided manufacturing (CAD/CAM) high-performance polymer (HPP group) or with light-curing composite core buildups of Tetric EvoCeram with (TECP group) or without (TEC group) a glass-fiber-reinforced post. All teeth were prepared to receive bonded glass ceramic crowns (Empress CAD luted with Variolink II) and were subjected to accelerated fatigue testing. Cyclic isometric loading was applied to the palatal cusp at an angle of 30° and a frequency of 5 Hz, beginning with a load of 200 N (×5000 cycles) and followed by stages of 400, 600, 800, 1000, 1200, and 1400 N at a maximum of 30,000 cycles each. Specimens were loaded until failure or to a maximum of 185,000 cycles. Groups were compared using the life-table survival analysis (log rank test at p=0.05). Average fracture loads and number of survived cycles were compared with one-way analysis of variance (Scheffé post hoc at p=0.05). RESULTS: None of the tested specimen withstood all 185,000 load cycles. There was a significant difference in mean fracture load, survived cycles, and survival; the HPP group (fracture load 975.27N±182.74) was significantly higher than the TEC (716.87N±133.43; p=0.001) and TECP (745.67±156.34; p=0.001) groups, and the TEC and TECP groups showed no difference (p=0.884). Specimens in the TECP group were affected by an initial failure phenomenon (wide gap at the margin between the buildup/crown assembly and the root). CONCLUSIONS: Semidirect core buildup made from high-performance polymer enhanced the performance of all-ceramic leucite-reinforced glass ceramic crowns compared with direct light-curing composite resin buildups. The use of a fiber-reinforced post system did not influence the fatigue strength of all-ceramic crowns.

Composite Resin Core Buildups With and Without Post for the Restoration of Endodontically Treated Molars Without Ferrule.

OBJECTIVE: The aim of this study was to investigate the restoration of highly damaged, broken-down endodontically treated molars without the ferrule effect using glass ceramic crowns on different dual-cure composite resin core buildups. METHODS AND MATERIALS: Thirty (N=30, n=15) decoronated, endodontically treated teeth (no ferrule) were restored without a ferrule with a direct buildup using the dual-curing composite Multicore HB (group MHB) or the dual-curing composite core buildup Multicore Flow in combination with glass-fiber-reinforced composite post (FRC post; group MFP). All teeth were prepared to receive bonded glass ceramic crowns (Empress CAD luted with Variolink II) and were subjected to accelerated fatigue testing. Cyclic isometric loading was applied to the palatal cusp at an angle of 30 degrees and a frequency of 5 Hz, beginning with a load of 200 N (×5000 cycles), followed by stages of 400, 600, 800, 1000, 1200, and 1400 N at a maximum of 30,000 cycles each. Specimens were loaded until failure or to a maximum of 185,000 cycles. Groups were compared using the life table survival analysis (log rank test at p=0.05). Average fracture loads and number of survived cycles were compared with one-way analysis of variance (Scheffé post hoc at p=0.05). Previously published data from the same authors about core buildups made of high-performance polymers (group HPP, n=15) and light-curing composite resin without FRC posts (group TEC, n=15) and with FRC posts (group TECP, n=15) using the same experimental setup were included for comparison. RESULTS: None of the tested specimen withstood all 185,000 load cycles. There was no significant difference in mean fracture load (p=0.376), survived cycles (p=0.422), and survival (p=0.613) between MHB (facture load 859.4 N±194.92) and MFP (796.13 N±156.34). Group HPP from a previous study appeared to have significantly higher performance than all other groups except MHB. All groups with posts were affected by an initial failure phenomenon (wide gap at the margin between the buildup/crown assembly and the root). CONCLUSIONS: HPP and MHB enhanced the performance of all-ceramic leucite-reinforced glass ceramic crowns, and insertion of a fiber-reinforced composite post was not influential when using other materials.

Use of a modified shell technique for three-dimensional bone grafting: description of a technique.

BACKGROUND: Defects of the alveolar crest often lead to three-dimensional bone loss after tooth extraction. Therefore, hard tissue grafting is required prior to implant placement. Different techniques have been described in the literature. METHODS: In this case report three-dimensional hard tissue grafting was performed with a modified shell technique and autogenous bone harvested from the mandibular ramus. The shells were trimmed to a thickness of 1 mm and placed to recontour the ideal shape of the alveolar ridge. The shells were then fixed with micro titanium screws, and the gap between the shells and the alveolar ridge was filled with autogenous bone chips. RESULTS: Wound healing was uneventful. Consolidation of the bone graft showed almost no resorption and the implant was placed into vital bone. CONCLUSIONS: The described shell technique for rebuilding three-dimensional alveolar defects showed promising results and could be an alternative treatment to other hard tissue grafting techniques.

Enhancing the predictability of complex rehabilitation with a removable CAD/CAM-fabricated long-term provisional prosthesis: a clinical report.

Implementing any definitive prosthetic treatment of the residual edentulous ridge involves several risks. The patient's expectations may not be completely fulfilled as such treatment procedures include major changes in function and esthetics. Innovative materials, such as high-density polymers based on a highly cross-linked polymethylmetacrylate (PMMA) or composite resin for CAD/CAM-manufacturing are an alternative treatment option. They enhance the predictability of complex rehabilitations, especially in situations where the prognosis of the residual ridge behavior over time is challenging. This article describes an innovative approach of an extended pretreatment phase by using intraoral scanning and CAD/CAM technology for the fabrication of a long-term provisional removable dental prosthesis made of high-density polymer.

Description and evaluation of a new approach on pre-clinical implant dentistry education based on an innovative simulation model.

INTRODUCTION: Predominantly theoretical courses are employed to teach German dental students in implant dentistry at pre-clinical stage. As implant dentistry is an important part of the clinical treatment spectra, practical implementation of this field at an early stage of education seems to be appropriate. By a newly developed interdisciplinary implant dentistry course, students should assess an improved competence level as well as first practical experiences in the field of implant dentistry at the pre-clinical stage of their education. MATERIALS AND METHODS: Interdisciplinary implant dentistry education was integrated in the final pre-clinical course Phantom II at the Department of Prosthodontics, LMU, Munich. In total 120 pre-clinical students participated at the implant dentistry education course. After theoretical introduction into implant surgery and implant prosthetics, 30 simulation units were employed for the practical training of the participants. All important treatment steps were carried out by the students under instruction by the supervisors, including interdisciplinary planning, the use of the drilling template, the template guided insertion of two implants, as well as the integration of two ball attachments into a pre-existing full denture. After the course participants were asked by questionnaire about the quality of the course and their personal opinion. RESULTS: The course received an extraordinary positive feedback. In total 108 students evaluated the course with the overall grade of 1.68 according to the German school-mark system (1 = excellent, 6 = unsatisfactory). Also the single parts of the course were voted constantly positively. CONCLUSION: The aim of this first interdisciplinary course for pre-clinical students was to enhance competence level and practical implementation of implant dentistry at an early stage of education. Participants' comments and suggestions on the questionnaires demonstrated the positive response and the general interest in this form of dental education, as well as the demand for further development of training in this field.