[How I do it - total maxillectomy via midfacial degloving]. / Oberkiefertotalresektion via Midfacial Degloving1.

Midfacial degloving for total maxillectomy in the case of a 67 year old male patient with a maxillary sinus adamantinoma of solid and multicystic plexiform differentiation is presented. This is the first report about surgical treatment of an adamantinoma via midfacial degloving. The importance of preoperative staging by means of computed tomography to exclude cheek infiltration and to plan the extension of maxillary resection is pointed out. The prognosis of the adamantinoma and its histopathological classification is discussed. The postoperative obturation of the resection defect and nasal cavity towards the oral cavity must be prepared preoperatively by the interdisciplinary care of dentistry and ENT surgery. Complete functional restoration of speech, swallowing and esthetic appearance can be achieved. Midfacial degloving for complete maxillectomy is rarely cited. Nevertheless it can be recommended for surgical treatment of maxillary tumours without spread in the cheek muscles and upper lip, even those which need total maxillectomy.

Marginal fit of alumina-and zirconia-based fixed partial dentures produced by a CAD/CAM system.

Clinical long-term success of all-ceramic dental restorations can be significantly influenced by marginal discrepancies. As a result, this in vitro study evaluated the marginal fit of alumina- and zirconia-based fixed partial dentures (FPDs) machined by the Precident DCS system. Different master steel models of three-, four- and five-unit posterior FPDs with an 0.8 mm chamfer preparation were produced. FPDs made of DC-Zirkon and In-Ceram Zirconia core ceramics were machined by the Precident DCS system. The marginal fit of the milled frameworks placed on the master steel models was determined by a replica technique using a light-body silicone to fill the discrepancies between crown and tooth and a heavy-body material to stabilize the light-body impression material. The impressions were poured into an epoxy resin material and each model was cross-sectioned with a low speed diamond saw to better visualize marginal discrepancies. The marginal fit of the FPDs was evaluated by scanning electron microscopy. The measurements of the marginal fit exhibited mean marginal discrepancies in a range between 60.5 and 74.0 microm, mean marginal gaps in a range from 42.9 to 46.3 microm, mean vertical discrepancies in a range from 20.9 to 48.0 microm and mean horizontal discrepancies in the range of 42.0 to 58.8 microm. Statistical data analysis was performed using the non-parametric test of Kruskal-Wallis and Mann-Whitney. The analysis revealed no significant differences (p>0.05) between the mean marginal gaps and vertical and horizontal discrepancies. However, for some FPDs the mean values of the marginal discrepancies were significantly different (p < or =0.05). The wide range of the measured values may be attributed to the complex geometrical design of long span FPDs and difficulties regarding the milling process of brittle ceramic materials. Based on the selection of 100 microm as the limit of clinical acceptability, the results of this study can conclude that the level of marginal fit for alumina- and zirconia-based FPDs achieved with the Precident DCS system meet the clinical requirements.

Fracture resistance of lithium disilicate-, alumina-, and zirconia-based three-unit fixed partial dentures: a laboratory study.

PURPOSE: The purpose of this study was to determine the fracture resistance of three-unit fixed partial dentures (FPD) made of new core ceramics. MATERIALS AND METHODS: A base metal three-unit master FPD model with a maxillary premolar and molar abutment was made. Tooth preparation showed 0.8-mm circumferential and 1.5-mm occlusal reduction and a chamfer margin design. FPDs were constructed with a uniform 0.8-mm-thick core ceramic and a porcelain veneer layer. In-Ceram Alumina, In-Ceram Zirconia, and DC-Zirkon core ceramics were machined by a computer-aided design/manufacturing system, whereas IPS Empress 2 core ceramic was indirectly built up using the fabrication technology of waxing and heat pressing. FPDs of IPS Empress were heat pressed as complete restorations without core material. To ensure standardized dimensions, the FPDs were controlled at different points. All FPDs were cemented with ZnPO4 on the master model and loaded on a universal testing machine until failure. The failure load and mode of failure were recorded. RESULTS: The highest failure loads, exceeding 2,000 N, were associated with FPDs of DC-Zirkon. FPDs of IPS Empress and In-Ceram Alumina showed the lowest failure loads, below 1,000 N, whereas intermediate values were observed for FPDs of IPS Empress 2 and In-Ceram Zirconia. Differences in mean values were statistically significant. CONCLUSION: The high fracture resistance evaluated for FPDs made of DC-Zirkon underscores the remarkable mechanical properties of high-performance ceramic, which could be useful for highly loaded all-ceramic restorations, especially in the molar region.

[Contamination of surgical wounds in the maxillofacial region with microoranisms]. / Die Kontamination von Operationswunden im Mund-, Kiefer- und Gesichtsbereich mit Mikroorganismen.

The analysis of 226 wound smears were statistically evaluated. Smears were taken immediately after beginning surgery (105) and during the course of the operation, usually toward the end (121). No bacteria were identified at the beginning of the operation in 11.6% of the smears; 8.6% of the smears taken toward the end of the operative procedure showed no bacteria. Microorganisms usually found in the buccal cavity were identified in approximately two thirds of the wounds. Every third or fourth wound contained facultative pathogenic bacteria at the beginning of the operation. The necessity of antimicrobial measures was discussed.