CAD-CAM denture teeth made on cast metal removable partial denture frameworks.

Once the fit of the cast metal framework on a removable partial denture (RPD) has been verified, the manufacturer's prefabricated denture teeth are typically secured on the cast metal framework to prepare for a wax evaluation. Although prefabricated denture teeth are available in different tooth forms and sizes, they require modification to fit an edentulous space. In arches with severe space discrepancy, it may be inefficient and time-consuming to make modifications to prefabricated denture teeth. The technique described uses digital technology to fabricate custom denture teeth on a cast metal framework and establish harmonious occlusion. An edentulous space with more than a single tooth replacement is designed as a splinted fixed partial denture with a connector. The designed teeth are milled in the double-cross-linked polymer to prepare for a wax evaluation, and once verified, the RPD is processed by using heat polymerization. Modifications are made to the milled denture teeth after wax elimination to reduce the likelihood of acrylic resin bond failure.

In vitro analysis of post-fatigue reverse-torque values at the dental abutment/implant interface for a unitarian abutment design.

PURPOSE: This study analyzed baseline and post-fatigue reverse-torque values (RTVs) for a specific brand control abutment relative to a third party compatible abutment. The purpose of this study was to compare the abutments' fatigue resistance to simulated function, using RTVs as an indication of residual preload at the implant/abutment interface. MATERIALS AND METHODS: Forty Straumann tissue-level implants were mounted in resin and divided into four groups (n = 10). Forty abutments were seated, 20 control and 20 third-party abutments, according to manufacturer guidelines. Ten abutments from each manufacturer were evaluated for RTV without fatigue loading, using a calibrated digital torque gauge to provide a baseline RTVs. Fatigue loading was carried out on the remaining ten specimens from each manufacturer according to ISO 14801 guidelines. A moving-magnet linear motor was used to load one specimen per sequence, alternating from 10 to 200 N at 15 Hz for 5×10(6) cycles. RTV was recorded post-fatigue loading. The results were subjected to two-sample t-testing and two-way ANOVA. Scanning electron microphotography was carried out on three specimens from both manufacturers at baseline and post-fatigue cycling to visualize thread geometry and the abutment/implant interface. RESULTS: The data indicated that mean post-fatigue RTV observed for the control group was significantly higher than the third-party group (RTV 42.65 ± 6.70 N vs. 36.25 ± 2.63 N, p= 0.0161). Visual differences at the macro/microscopic level were also apparent for thread geometry, with third-party abutments demonstrating considerably greater variation in geometrical architecture than control specimens. CONCLUSIONS: Within the limitations of this in vitro model, the effect of component manufacturer resulted in a significantly higher RTV in the control group (two-way ANOVA, p= 0.0032) indicating greater residual preload; however, there was no significant decrease in post-fatigue RTV for either manufacturer compared to baseline.

Clinical, Etiological, and Therapeutic Features of Jaw-opening and Jaw-closing Oromandibular Dystonias: A Decade of Experience at a Single Treatment Center.

BACKGROUND: Dystonia is a heterogeneous hyperkinetic disorder. The anatomical location of the dystonia helps clinicians guide their evaluation and treatment plan. When dystonia involves masticatory, lingual, and pharyngeal muscles, it is referred to as oromandibular dystonia (OMD). METHODS: We identified patients diagnosed with OMD in a Movement Disorders Clinic and Laryngeal Movement Disorders Clinic from a single institution. Demographic, etiological, clinical, and therapeutic information was retrospectively reviewed for patients with jaw-opening (O-OMD) and jaw-closing (C-OMD) OMD. RESULTS: Twenty-seven patients were included. Their average age of onset was in the sixth decade of life and there was a female predominance. Etiological factors linked in this study to OMD included a family history of dystonia or essential tremor, occupation, cerebellar disease, a dental disorder, and tardive syndrome. Clinically, patients with C-OMD presented with more prominent feeding difficulties, but seemed to respond better to therapy than those with O-OMD. In addition to the known benefits of botulinum toxin therapy, patients who described sensory tricks obtained benefit from the use of customized dental prosthesis. DISCUSSION: This works provides useful information on potential etiological factors for OMD and its response to therapy, and highlights the potential benefit of dental prosthesis for the treatment of OMD.

Fabricating custom provisional restorations for the ITI solid abutment system.

This article describes a technique for the quick and accurate fabrication of custom acrylic resin provisional restorations for the ITI implant system. Materials and procedures common to fixed prosthodontics are used. The technique should necessitate no more chairtime than the fabrication of custom acrylic provisional restorations for conventional fixed prostheses.

Tensile bond strength of acrylic resin denture teeth to a microwave- or heat-processed denture base.

STATEMENT OF PROBLEM: Fracture of acrylic resin prosthetic teeth from acrylic resin denture bases can be a problem for some patients. The optimal combination of acrylic resin denture tooth, denture base material, and processing method is not known. Purpose. The objective of this study was to compare the tensile bond strengths of heat- and microwave-polymerized acrylic resins among 4 types of acrylic resin denture teeth. MATERIAL AND METHODS: Heat-polymerized (Lucitone 199) and microwave-polymerized (Acron MC) acrylic resins were used. Four types of acrylic resin denture teeth (IPN, SLM, Vitapan, and SR-Orthotyp-PE) were milled to a fixed diameter according to ADA specification no. 15. Ten specimens of each tooth type were processed to each of the denture base materials according to the manufacturers' instructions. Ten additional resin control specimens without teeth also were fabricated. Specimens were thermocycled and tested for strength until fracture with a custom alignment device. Data were analyzed with analysis of variance and Duncan's multiple range test. A scanning electron microscope was used to identify adhesive and cohesive failures within debonded specimens. RESULTS: The mean force required to fracture the specimens ranged from 5.3 +/- 3.01 to 21.6 +/- 5.2 MPa for the microwave-polymerized base and 11.2 +/- 3.0 to 39.1 +/- 5.1 MPa for the heat-polymerized base. The most common failure was cohesive within the denture tooth. With each base material, Orthotyp and IPN teeth exhibited the highest bond strengths; SLM and Orthotyp bond strengths were similar. In general, heat-polymerized groups failed cohesively within the denture base resin or the tooth, and microwave-polymerized groups failed adhesively at either the ridge lap or occlusal surface of the denture tooth. CONCLUSION: Within the limitations of this study, the results suggest that the type of denture base material and denture tooth selected for use may influence the tensile bond strength of the tooth to the base. Selection of more compatible combinations of base and resin teeth may reduce the number of prosthesis fractures and resultant repairs.