Wired/Classic and Wireless/Periotest "M" instruments: an in vitro assessment of repeatability of stability measurements.

This in vitro study evaluated agreement among 10 trained evaluators when assessing implant stability with the Wired/Classic and Wireless/Periotest "M." A difference of 1 Periotest value (PTV) between the wired (-7) and wireless (-8) instruments was observed for the pretest calibration ring. No significant differences were found between the instruments and for all evaluators for all tests (analysis of variance, P < .05). Each instrument can provide meaningful and reproducible recordings of stability measurements.

The use of root form implants in overdenture treatment for the atrophic mandible: a clinical report.

Four short root form implants were inserted in an atrophic mandible and the case restored with a lower connecting bar and an overdenture, opposing a complete maxillary denture. Root form implants were selected, as opposed to a subperiosteal implant in this case. The patient had a favorable medical history, appeared healthy, did not smoke, drink, or do illicit drugs, and had good bone quality.

Metal bases for implant overdentures.

Reinforcement of implant overdenture bases with chromium alloys offers a number of advantages that offset the initial greater cost. These bases offer increased strength, the ability to detect thermal changes, and the option for use when space is at a minimum. Both acrylic resin and chromium alloy have long (approximately 80 years), successful histories as accepted dental materials. Low-heat (nickel) or high-heat (cobalt) chromium alloys can be used with equal success.

Extraordinary implant failure.

Every attempt must be made to keep implant failures to a minimum. Dental implant failure can roughly be divided into 3 broad categories: bacterial factors, occlusal (mechanical factors), and systemic and psychologic factors. All failures should be carefully analyzed and evaluated to identify their causes in order to prevent future reoccurrence. Failures should be documented and used to advantage when treatment planning future implant cases. A panoramic radiograph, mounted diagnostic casts, medical and dental histories, and surgical guides are accepted standards of care prior to beginning oral implant procedures. The identification and management of nutritional deficiencies is a useful adjunct to successful implant treatment.

The effect of fiber dowel heights in resin composite cores on restoration failures of endodontically treated teeth.

In vitro and in vivo testing suggest that fiber posts may reduce the incidence of root fractures of endodontically treated teeth. The purpose of this in vitro study was to compare the effect of fiber post height in resin composite cores on the fracture resistance of endodontically treated teeth. Forty maxillary central incisors were randomly divided into 2 control groups (Groups 1 and 2) of 5 teeth each, and 3 experimental groups (Groups 3, 4, and 5) of 10 teeth each. The teeth in Group 1 had their opening restored with composite resin, the teeth in Group 2 were restored with quartz fiber posts without resin composite cores, and the teeth in Groups 3, 4, and 5 were restored with quartz fiber posts of 2, 4, and 6 mm high, respectively, in 6-mm resin composite cores. Ceramic crowns were fabricated for the specimens. Specimens were positioned in a mounting device and aligned at a 130-degree angle to the long axis of each tooth. A universal testing machine was used to apply constant load at a crosshead speed of 0.5 mm/min until failure occurred. The highest fracture load and mode of failure of each specimen was recorded. The highest fracture resistance force was observed in Group 2 (290.38 +/- 48.45 N) and decreased, respectively, in Group 1 (238.98 +/-26.26 N), Group 5 (228.35 +/-58.79 N), Group 4 (221.43 +/-38.74 N), and Group 3 (199.05 +/-58.00 N). According to one-way analysis of variance (ANOVA) and Duncan's test (P < or = .05), there was no statistically significant increase in the force from Group 3 to Group 5, and the force in Group 2 was significantly higher than that of the experimental groups. There was no statistical significance difference in force among the experimental groups, and the amount of residual tooth structure was found to be the critical factor in fracture resistance. The results suggest that endodontically treated teeth should be restored with the longest possible post height while preserving maximum tooth structure.

Implant replacement of congenitally missing lateral incisors: a case report.

Implants can readily be placed and restored in congenitally missing maxillary lateral incisor sites with predictable results if surgical, periodontal, and prosthodontic conditions are favorable. A case report using dental implants to replace bilateral congenitally absent maxillary lateral incisors for teenage female identical twins is presented.

Microtensile bond strength of resin-resin interfaces after 24-hour and 2-month soaking.

Evaluate the bond strengths of denture base-repair materials to minimize recurrent failure rate. Use microtensile bond strength (muTBS) testing to evaluate the interfacial bonding strength of 6 commercial denture repair materials after 24-hour and 12-month soaking. Blocks of poly(methyl metacrylate) (PMMA) and Triad were fabricated, fractured, and repaired. Twenty bars (1 x 1 x 30 mm) per group were sectioned from each block parallel to the long axis and approximately 90 degrees to the resin-resin repair interface and stored before muTBS testing in a servo-hydraulic tensile-testing machine. Intact PMMA and Triad bars that had been soaked for 24 hours and 12 months were tested for reference. The 24-hour repair strengths for PMMA ranged from 52% to 84% of original strength. Soaking for 12 months resulted in a 20% decrease in strength for the PMMA control. The 12-month repair strengths for PMMA ranged from 43% to 74% of the 12-month soaked material strength. Triad repair tested 35% of original strength after soaking for 24 hours. Permabond (cyanoacrylate) to PMMA tested 47% of original strength after 24 hours of soaking and 26% of the 12-month soaked material strength. Permabond to Triad tested 30% of original strength after 24 hours of soaking. Permabond and Triad showed a 100% adhesive mode of failure. All other materials tested exhibited either an adhesive mode of failure at the denture base-repair-material interface or a complex cohesive failure within the repair-material interface. The muTBS approach can be used to analyze the resin-resin interface of repaired acrylics. The relatively small standard deviations make the muTBS approach attractive. In this study, muTBS was used to evaluate the repair strength of 6 denture repair materials enabling clinicians to make clinical judgments regarding the strongest repair bond available.

Shade matching by dental students.

Dental students achieved a high identification rate for darker shades (P14 and P24) on the Portrait IPN shade guide, which represent the highest chroma and lowest value in the grayish and reddish yellow hue groups. A high identification rate was also obtained for P32, representing the lowest chroma and highest value in the reddish gray hue group. The data suggest that dental students had the most difficulty determining the correct hue group for unmarked shade tabs. Incorrect responses tended to remain in the same value and chroma range but were selected in a different hue group.

Prosthodontic self-treatment with acrylic resin super glue: a case report.

A case history is presented of a patient who fabricated 3 prostheses from autopolymerizing acrylic resin intended for fingernail augmentation and then cemented them into her mouth with super glue. Patients must be warned not to attempt self-treatment for esthetics with self-fabricated prostheses because severe adverse and irreversible hard and soft tissue reactions may occur.

The effect of compressive cyclic loading on retention of a temporary cement used with implants.

Masticatory forces cause fatigue to cement-retained crowns and abutments and may adversely effect retention. The relation between the number of load cycles and the retentive forces is important. This study evaluated the effect of compressive cyclic loading on the retentive forces of a temporary cement used to retain implant crowns and the relationship between load cycles and retentive forces. Ten castings and implant abutments were cemented with zinc oxide-eugenol temporary cement. The retentive force necessary to dislodge the casting from the abutment was determined before and after the application of 2 Hz of vertical off-axis 3-mm sinusoidal-type compressive cyclic loading between 20 and 130 N for 500000, 1000000, and 5000000 cycles. These forces were equivalent to approximately 6 months, 1 year, and 5 years of human mastication. Data before and after the applied loading were analyzed with a paired sample t test (alpha = 0.05). The retentive forces of the 3 groups were analyzed by 1-way analysis of variance and post hoc by Scheffé multiple comparison (alpha = 0.05). The relation of the loading and the altered retentive forces were analyzed with the Pearson correlation coefficient. Compressive cyclic loading reduced the retentive forces significantly in all groups (P = .000). The retentive forces were reduced 16.75%, 18.73%, and 19.68% during the applied loading cycles of 500000, 1000000, and 5000000. All reduced retentive forces were not significantly different (P = .792). Although cyclic loading reduced the retentive forces, the increased cycles had little relationship (R = 0.119) to the decreased retentive forces of the temporary cement. The relationship between occlusal loading and retentive force can influence the choice of a temporary cement for a particular clinical situation.

An interim denture technique and case reports.

An interim denture technique is presented describing the fabrication of an esthetic prosthesis that is used for short periods of time. The prosthesis conditions the patient for the acceptance of an artificial substitute for missing natural teeth until more definitive prosthodontic therapy can be provided. All the teeth in the arch are extracted simultaneously, and the interim prosthesis is inserted immediately thereafter. The prosthesis duplicates the morphology, color, and position of the extracted teeth. This technique satisfies a great need of socially and business-active patients because there is no interruption in their activities and no change in facial esthetics. Two case histories are presented.