Volumetric misfit in CAD/CAM and cast implant frameworks: a university laboratory study.

PURPOSE: To compare the volumetric misfit between implant restorative platforms of implants and implant frameworks manufactured with two different technologies. One set of implant frameworks was made with a CAD/CAM protocol and a tactile probe; the second protocol consisted of frameworks made with the lost-wax technique and conventional casting technology. MATERIALS AND METHODS: In this laboratory study, an acrylic resin model with five "inter-foraminal" implants was used as the "patient" model. Implant level impressions were made, and 10 definitive master casts were fabricated. The casts were verified using an index made on the patient model. Five cast high palladium noble alloy and five CAD/CAM titanium alloy frameworks were fabricated. The patient's implants and the frameworks' implant restorative platforms were scanned with a tactile probe, and the data were digitized. The digitized implant restorative platforms of the frameworks were fit onto the patient's digitized implants via a software program, in a process called "lofting." This computerized procedure simulated a 1-screw test; the process was performed on both sides. The volumetric misfit between the implant restorative platforms of the frameworks and the patient's implants were measured. A Welch's t-test was used to determine significant differences (p < 0.05) between the misfit of the two technologies. Wilcoxon Signed-Rank tests were used to evaluate differences between the right and left sides. RESULTS: On average, the volumetric misfit of the CAD/CAM frameworks was 1.8 mm(3) less than the volumetric misfit of the cast alloy frameworks (p < 0.05). The Wilcoxon Signed-Rank tests showed no significant differences between the right and left sides within both systems (p > 0.05). CONCLUSIONS: The scanning technology and computer software program used in this study demonstrated that the CAD/CAM implant frameworks had statistically significantly less volumetric misfit when compared with the cast implant frameworks. There were no significant differences between the right and left 1-screw tests within the same type of frameworks.

Surgical and prosthodontic treatment of a patient with significant trauma to the middle and lower face secondary to a gunshot wound: a clinical report.

Large defects of dentofacial structures may result from trauma, disease (including neoplasms), and congenital anomalies. The location and size of the defects are related to difficulties that patients report relative to speech, mastication, swallowing, facial esthetics, and self-image. This article reports on the evaluation and treatment of a patient who suffered significant trauma to the lower and mid-face secondary to a gunshot injury. It describes the initial presentation, life-saving procedures, and subsequent bone grafts, implant placement, and prosthetic treatments required to rehabilitate the patient to a condition that closely approximated his preoperative condition. This clinical report confirms that no matter the degree of complexity involved in treating the results of significant facial trauma, successful treatment is dependent on thorough physical and radiographic examinations, development of the appropriate diagnoses, and treatment based on sound prosthodontic and surgical principles.

Treatment of an edentulous patient with CAD/CAM technology: a clinical report.

CAD/CAM (computer-aided design/computer-aided manufacturing) technology with large-scale industrial applications has been developed and used over the last 3 decades. Implant Innovations, Inc. (Palm Beach Gardens, FL), has recently introduced a version of this technology for use in implant restorative dentistry. Different software programs were written to design and machine individual implant abutments and bar-type frameworks. This report provides a literature review of CAD/CAM technology in dentistry and describes the treatment of one edentulous patient restored with individual implant abutments and conventional cemented fixed partial dentures in the edentulous maxilla and a fixed, screw-retained prosthesis that replaced the missing mandibular teeth. The abutments were made using The Encode Restorative System; the mandibular framework was made with a CAM StructSURE Precision Milled Bar. The benefits and limitations of this technology are also discussed. Additional clinical and laboratory studies are needed to further validate this technology.

A retrospective analysis of osseotite NT implants in clinical practice: 1-year follow-up.

This article reports the preliminary results from a clinical study involving the use of implants with a natural taper design in edentulous and partially edentulous patients. Implants were followed for at least 12 months after occlusal loading. Three hundred nine implants were placed by two periodontists (176 maxillary, 133 mandibular; 198 anterior, 111 posterior). Digital radiographs were taken immediately after implant placement and 1 year after occlusal loading. Computerized measurements were made, with distances calculated between the implant restorative platforms and the greatest heights of interproximal bone on both interproximal surfaces at the time of implant placement and 12 months postplacement. At the 12-month recall appointments, it was noted that 8 of the 309 implants had failed. Osseotite NT implants can be used in the treatment of edentulous and partially edentulous patients using two-stage, single-stage, and immediate occlusal loading protocols with survival rates equivalent to those seen for cylindrically shaped implants.

Two new clinical/laboratory protocols for CAD/CAM implant restorations.

BACKGROUND: Conventional casting technology has some disadvantages for dental laboratory technicians and restorative dentists, including porosity of restorations, miscasting and inaccuracy. It also is labor-intensive. Computer-aided design/computer-aided manufacturing (CAD/CAM) technology was developed in the late 1980s for dentistry, and it significantly reduced and/or eliminated problems associated with dental castings. The purpose of this article is to give readers an overview of the use of CAD/CAM technology for dental implants and illustrate two clinical protocols for that use. CLINICAL IMPLICATIONS: The CAD/CAM technology described in this article can reduce restorative dentists' chairside time associated with implant treatment in both edentulous and partially edentulous patients, can decrease costs without sacrificing accuracy or biocompatibility for both clinicians and dental laboratory technicians, and is available to dental laboratories without the capital expenses associated with purchasing new technology.

A clinical report on the 18-month cumulative survival rates of implants and implant prostheses with an internal connection implant system.

Titanium implants have been successful in both dentulous and edentulous patients. The original Brånemark titanium implants were introduced with external hex connections between implants and abutments. Successes and failures/complications with both the biology and mechanics of this connection system have been reported. In an attempt to improve the predictability and success of implant/abutment connections, internal connections between implants and abutments were developed significantly differently from external implant/abutment connections in terms of size, surface area, and geometry. Forty-five consecutive partially edentulous patients were treated with 83 implants (Osseotite Certaina). The implants were allowed to heal for at least 8 weeks without occlusal loading. All were restored with single, nonsplinted restorations. The implants were loaded with fully functional occlusions for at least 1 year. Recall appointments were scheduled at 1, 6, 12, 18, 24, and 36 months after implant placement. Eighty-two of the 83 implants were clinically stable and considered to be osseointegrated 18 months after occlusal loading for a cumulative survival rate (CSR) (implants) of 100%. All of the abutment screws and restorations were non-mobile 18 months after occlusal loading for a CSR (prostheses) of 100%. This internal implant/abutment connection was clinically successful and should benefit restorative dentists involved in implant dentistry by decreasing the number of maintenance visits and problems associated with dental implant treatment.

Immediate occlusal loading of Osseotite implants in mandibular edentulous patients: a prospective observational report with 18-month data.

PURPOSE: To evaluate the efficacy of treatment consisting of placement and immediate occlusal loading of implants in 27 patients with edentulous mandibles. MATERIALS AND METHODS: Twenty-seven patients were treated in two private practice settings. One hundred fifty-one implants were placed and immediately occlusally loaded with fixed implant prostheses (15 cement-retained, 12 screw-retained) on the day of implant placement. The implant-retained prostheses were inserted within 5 hours of implant placement. Patients were followed for at least 18 months. The required criteria for immediate occlusal loading was primary implant stability of at least 30 Ncm of insertion torque. The implant prostheses were removed at least 12 months post-placement and the implants were evaluated for primary clinical stability and radiographic bone apposition to implants. RESULTS: At the 12-month follow-up appointments, cumulative survival rates of 98.0% and 100% were recorded for implants and prostheses, respectively. Three implants failed within 3 months. All other implants were clinically successful. CONCLUSIONS: Immediate occlusal loading of multiple, splinted mandibular implants is an effective treatment when implants are stable at insertion and are rigidly splinted with implant-retained prostheses.

Treatment of edentulous and partially edentulous patients with CAD/CAM frameworks: a pilot case study.

Computer-assisted design/computer-assisted manufacturing (CAD/CAM) has been used successfully in commercial industry for several decades and is only now becoming more common for use within the clinical setting. This presentation will outline how CAD/CAM frameworks present numerous advantages over conventional castings when used to treat edentulous and partially edentulous patients in such areas as strength, biocompatibility, and precision machining. Recent advancements in CAD/CAM technology have decreased the costs associated with the fabrication of implant- and tooth-borne frameworks.

Immediate provisional restoration of Osseotite implants: a clinical report of 18-month results.

PURPOSE: The purpose of this study was to assess the survival rates and interproximal bone levels for Osseotite implants that were restored with fixed provisional crowns without occlusion immediately after implant placement. MATERIALS AND METHODS: Ninety-three implants were placed in 38 partially edentulous patients. All implants were immediately restored with prefabricated abutments and cement-retained provisional crowns without centric or eccentric occlusal contacts. The implants were restored with definitive restorations approximately 8 to 12 weeks after implant placement. All patients included in the study were followed for at least 18 months after implant placement (average 20.3 months). RESULTS: Seventy-seven of the 93 implants satisfied the inclusion criteria. Seventy-five implants became osseointegrated. The overall survival rate was 97.4%. Radiographic bone loss 18 months after implant placement (the mean of both interproximal surfaces) was 0.76 mm. The exact binomial confidence interval was 0.32% to 9.07%. For the exact binomial test with the null hypothesis proportion = .05, P was .3334 and was not statistically significant. DISCUSSION: Immediate nonocclusal loading of single-unit dental implants differs from immediate loading of multiple, splinted implants. Unsplinted, restored implants without occlusal loading may still be subject to lateral and occlusal loads secondary to the proximate location of the food bolus. Immediate restoration of dental implants significantly reduces treatment time and may be beneficial in reducing the morbidity associated with loss of teeth, contraction of the alveolus, and loss of interdental papillae associated with the traditional method of treatment following tooth loss. CONCLUSIONS: The results of this study suggest that immediate restoration of Osseotite implants can be accomplished with results that are similar to the results obtained with the traditional 1- or 2-stage surgical, unloaded healing protocols.

A retrospective comparison of two definitive impression techniques and their associated postinsertion adjustments in complete denture prosthodontics.

PURPOSE: To compare the number of postinsertion adjustment visits required by edentulous patients whose dentures were made from border-molded definitive impressions using modeling plastic impression compound (traditional technique) with patients whose dentures were made from border-molded definitive impressions using heavy-body vinyl polysiloxane impression material. MATERIALS AND METHODS: In this retrospective clinical study, 78 patients were treated with the traditional technique (custom impression trays border molded with gray modeling plastic impression compound) and 78 were treated with the modified technique (custom impression trays border molded with heavy-body vinyl polysiloxane impression material). In both techniques, definitive wash impressions were made with light-body vinyl polysiloxane impression material. Postinsertion visits were quantified for 1 year after the dentures were inserted. RESULTS: The average number of adjustment visits for patients treated with the traditional technique was 2.68. The average number of adjustment visits for patients treated with the modified technique was 2.68. The data were compared using Student t tests. There was no significant difference in the number of adjustments required for patients whose dentures were made with either technique (t = 0.000, p = 1.00). There was no significant difference in the number of post-insertion visits required by patients from either population. CONCLUSIONS: Within the limitations of this clinical study, border-molding custom denture impression trays with vinyl polysiloxane impression material provided similar results in terms of postinsertion visits for one year as compared to dentures made from impressions border molded with modeling plastic impression compound.

A clinical study of the efficacy of gold-tite square abutment screws in cement-retained implant restorations.

PURPOSE: The purpose of this study was to record the effectiveness of Gold-Tite square abutment screws, tightened to 35 Ncm with a torque indicator, in maintaining a clinically stable implant/abutment connection. MATERIALS AND METHODS: The study consisted of 73 patients who were treated with 110 Osseotite implants. All patients were restored with either pre-machined titanium or customized UCLA hexed abutments. All abutments were fabricated per the Gold Standard ZR abutment design of Implant Innovations. All of the abutment screws were Gold-Tite square abutment screws. They were torqued to 35 Ncm with a torque indicator at the time of abutment connection. All crown restorations were cemented to the abutments. Patients were followed for at least 1 year post-occlusal loading. RESULTS: Four patients with 6 implants were lost between the 6- and 12-month recall appointments. Clinical assessments of implant/restoration mobility were made by the author. One abutment screw was found to be loose at the 12-month recall appointment, representing a 99% survival rate. DISCUSSION: These results add to the growing evidence that abutment screws with enhanced surfaces may provide increased screw/implant contact, higher rotational values, and calculated preload values. CONCLUSION: The use of the Gold-Tite square abutment screws, torqued to 35 Ncm, maintained a stable implant/abutment connection that was successful in clinical practice for this minimal evaluation period.