Measuring mobility of 2 dental implant fixtures of different configurations: an in vitro study.

OBJECTIVES: To our knowledge, it has not as yet been determined if mini-dental implants can be used as a long-term treatment method compared to endosseous standard root-form dental implant fixtures. This in vitro study investigates the stability of 2 different implants, 1 mini-dental implant and 1 endosseous standard root form dental implant, under lateral forces. METHODS: There were 2 different screw-type dental implants with the O-ring/ball attachment prosthetic heads used. A mini-dental implant (Sendax MDI MAX; IMTEC, Corp., Ardmore, OK) 13 mm in length and 2.2 mm in diameter, and root form implant (Brånemark; Nobel Biocare AB, Goteborg, Sweden) 13 mm in length and 4 mm in diameter. These implants were then embedded into a matrix mixture of pumice, two-fifths BaSO4 powder and one-fifth plaster. Parallel periapical radiographs were taken pretest and after lateral forces were applied. The implants were vibrated using electric toothbrushes. They were attached to O-rings on the implants. Periapical radiographs were secured periodically every 5 minutes. The first discrepancy was observed at the 35th minute. Mobility and discrepancy values were recorded at the instances of 35th, 60th, 90th, and 120th minutes. Stability was measured and recorded using a manual stress and tension gauge. Radiographic discrepancy values were measured using a stereomicroscope. RESULTS: The Brånemark implant showed less mobility and discrepancy values than the mini-dental implant. The discrepancies were observed mostly at the cervical region of the 2 implants. CONCLUSIONS: According to the experimental results of this study, the Brånemark implant was more stable than the mini-dental implant at the end of 2 minutes.

An in vitro comparison of cast metal dowel retention using various luting agents and tensile loading.

STATEMENT OF PROBLEM: No clear consensus exists regarding the choice of luting agents for the retention of cast metal dowels used as a treatment alternative for endodontically treated teeth with excessive loss of coronal tooth structure. PURPOSE: The purpose of this in vitro study was to investigate the retention of the dowel/luting agent/tooth complex while applying different luting agents to cast metal dowels under vertical tensile loading. MATERIAL AND METHODS: Sixty extracted, noncarious mandibular premolars with roots of approximately 15-mm length were selected. For each tooth, a tapered root canal preparation was completed to a maximum diameter of 1.60 mm and a length of 11 mm, a common clinical configuration to accommodate cast metal dowels. Sixty cast metal dowels were fabricated for the tooth specimens and cemented with 1 of 3 luting agents (n = 20): zinc-phosphate cement (ZPC) as a control, phosphate-methacrylate resin luting agent (PMRL, Panavia F), and phosphate-methacrylate resin luting agent with metal dowel surfaces modified with a silane coating technique (PMRLS, Panavia F + Siloc). Tensile bond strength (TBS) of the specimens was measured with a universal testing machine at a crosshead speed of 0.5 mm/min. Data (kg) were statistically analyzed using a 1-way analysis of variance and a Scheffe multiple range test (alpha=.05). The homogeneity of variances was analyzed using the Levene test. RESULTS: The TBS values of ZPC (34.2 +/- 10.54 kg) were significantly higher than PMRL (22 +/- 9.57 kg) and PMRLS (21.7 +/- 7.64 kg). There was no significant difference between the PMRL and PMRLS groups. CONCLUSION: Within the limitations of this study, the use of zinc-phosphate cement provided greater TBS for cast metal dowels than the resin luting agent with and without the silane coating technique. The TBS values with and without the silane coating technique were not statistically different.