Technique for using an implant driver and tether system.

An implant driver and tether system is described as a metal driver body and handle, a shaft for accepting a tether, and a distal end flange. The tether can be made of a soft material, such as silicone, and includes a retaining aperture, an elongated body, and a finger-securing aperture. During use, the tether is attached to the driver body by slipping the distal end flange of the driver body through the retaining aperture of the tether. The torque wrench is then attached to the handle of the driver.

Survival of cast-metal, resin-bonded fixed partial dental prostheses after nearly 20-year follow-up: A retrospective study.

STATEMENT OF PROBLEM: Cast-metal resin-bonded fixed partial dental prostheses (RBFPDPs) are a conservative approach to replacing missing teeth. Despite their recognized advantages, the use of cast-metal RBFPDPs as a definitive option remains somewhat controversial because of the lack of long-term studies on their success. PURPOSE: The purpose of this retrospective study was to evaluate the long-term survival rate of cast-metal RBFPDPs and investigate the influence of covariates such as sex, type of prosthesis, location, number of pontics, abutments, and type of luting cement on the survival of bonded prostheses. MATERIAL AND METHODS: This study evaluated 209 cast-metal RBFPDPs cemented in 181 patients (mean 41.06 ±11.90 years of age) treated in the principal author's private practice between July 1993 and May 2012. Data sheets were completed at the patients' recall examination at regular intervals or if seen for complications. Kaplan-Meier analysis was used to evaluate the survival rate of the prostheses before debonding. The Cox model and Wald test were used to analyze the prognostic factors (α=.05). RESULTS: A total of 198 prostheses were studied. Eleven cast-metal RBFPDPs were lost to follow-up. This study evaluated the effect of different variables on the survival rate of both conventional RBFPDPs (wing-wing) and combination resin-bonded FPDPs (wing-crown) types. Survival rate was divided into "with repair" and "without repair" groups. The mean survival time was 102.24 months for the group with no repair and 119.76 months for the group with repair. The survival rate after 5, 10, and 15 years was 86%, 42%, and 15% with repair, whereas 69%, 32%, and 14% of the prostheses survived without repair. CONCLUSIONS: In appropriate clinical conditions and selected patients, cast-metal RBFPDPs were a viable treatment option with an acceptable survival rate.

Maxillary lateral incisor agenesis and its relationship to overall tooth size.

STATEMENT OF PROBLEM: Agenesis of the maxillary lateral incisor has been linked to differences in the size of the remaining teeth. Thus, the mesiodistal space required for definitive esthetic restoration in patients with missing maxillary lateral incisors may be reduced. PURPOSE: The purpose of this study was to determine whether a tooth size discrepancy exists in orthodontic patients with agenesis of one or both maxillary lateral incisors. MATERIAL AND METHODS: Forty sets of dental casts from orthodontic patients (19 men and 21 women; mean 15.9 years of age; all of European origin) were collected. All casts had agenesis of one or both maxillary lateral incisors. Teeth were measured with a digital caliper at their greatest mesiodistal width and then compared with those of a control group matched for ethnicity, age, and sex. Four-factor ANOVA with repeated measures of 2 factors was used for statistical analysis (α=.05). RESULTS: Orthodontic patients with agenesis of one or both maxillary lateral incisors exhibited smaller than normal tooth size compared with the control group. The maxillary arch had a larger tooth size difference between the control and test groups than the mandibular arch (there was a significant Jaw × Group interaction [F=4.78, P=.032]). CONCLUSIONS: Agenesis of one or both maxillary lateral incisors is significantly associated with tooth size discrepancy, which may affect the space remaining for restoration of the remaining teeth.

Use of intraoral digital scanning for a CAD/CAM-fabricated milled bar and superstructure framework for an implant-supported, removable complete dental prosthesis.

This report describes a clinical technique for fabricating a maxillary implant-supported, removable complete dental prosthesis by using an intraoral digital scanner to register implant positions and soft tissue morphology. The presented technique uses computer-aided design/computer-aided manufacturing (CAD/CAM) technology with a subtractive manufacturing process to fabricate a milled bar (infrastructure framework) and an additive process to fabricate a friction fit, superstructure framework. This digital restorative pathway may decrease patient discomfort and reduce the labor associated with fabricating implant-supported, removable complete dental prostheses.

Effect of occlusal vertical dimension on lip positions at smile.

STATEMENT OF PROBLEM: In complete mouth reconstructive dentistry, the occlusal vertical dimension may be increased to provide adequate restorative space or to improve esthetics. The effect of increasing the occlusal vertical dimension on the smile is not well understood. PURPOSE: The purpose of this study was to evaluate the effect of increasing the occlusal vertical dimension on the dimensions of the smile. MATERIAL AND METHODS: Thirty dental students, 12 men and 18 women between the ages of 21 and 30 years old, participated in this study. Polyvinyl siloxane occlusal registrations 2, 4, 6, and 8 mm in thickness were fabricated from articulated stone casts. Posed smile images at occlusal vertical dimension +0, +2, +4, +6, and +8 mm were made with a digital single lens reflex camera mounted on a tripod. A wall-mounted head-positioning device, modified from a cephalometric unit, was used to stabilize the head position. Interlabial gap height, intercommissural width, incisal edge to upper lip, and incisal edge-to-lower lip measurements were made with computer software. The smile index was obtained by dividing width by height. The display zone area was measured by using computer software tracing. One-way repeated measures ANOVA (α=.05) was used for statistical analysis. RESULTS: With an increase in the occlusal vertical dimension, the interlabial gap height, incisal edge to lower lip distance, and display zone area increased significantly (P<.001), whereas the smile index decreased significantly (P<.001). No significant changes were observed in the intercommissural width and incisal edge to upper lip distance. CONCLUSIONS: The interlabial gap height, incisal edge-to-lower lip distance, and display zone area increase with increased occlusal vertical dimension. The smile index decreases with increased occlusal vertical dimension. However, the width of the smile and the length of the upper lip tend to remain unchanged.

Satisfaction of Dental Students, Faculty, and Patients with Tooth Shade-Matching Using a Spectrophotometer.

The aims of this study were to evaluate dental students' clinical shade-matching outcomes (from subjective use of shade guide) with an objective electronic shade-matching tool (spectrophotometer); to assess patients', students', and supervising faculty members' satisfaction with the clinical shade-matching outcomes; and to assess clinicians' support for use of the spectrophotometer to improve esthetic outcomes. A total of 103 volunteer groups, each consisting of patient, dental student, and supervising faculty member at the University of Louisville, were recruited to participate in the study in 2015. Using the spectrophotometer, clinical shade-matching outcome (ΔEclinical) and laboratory shade-matching outcome (ΔElaboratory) were calculated. Two five-point survey items were used to assess the groups' satisfaction with the clinical shade-matching outcome and support for an objective electronic shade-matching tool in the student clinic. The results showed that both ΔEclinical (6.5±2.4) and ΔElaboratory (4.3±2.0) were outside the clinical acceptability threshold ΔE values of 2.7, when visual shade-matching method (subjective usage of shade guide) was used to fabricate definitive restorations. Characteristics of the patients, dental students, supervising faculty members, and restorations had minimal to no effect on the ΔEclinical The patients, dental students, and supervising faculty members generally had positive opinions about the clinical shade-matching outcome, despite the increased ΔEclinical observed. Overall, clinical shade-matching outcomes in this school need further improvement, but the patients' positive opinions may indicate the need to revisit the acceptability threshold ΔE value of 2.7 in the academic setting.

Dentin surface modification using the Er,Cr:YSGG laser and a meshwork mask: light and SEM microscopic observations.

OBJECTIVE: We have developed a novel technique of utilizing a stainless steel meshwork mask during treatment of dentin with the Er,Cr:YSGG laser. It is the purpose of this study to observe the surface modifications produced by this method. BACKGROUND DATA: Many techniques have been developed to facilitate bonding of various materials to dentin. However, an optimal bond has not yet been achieved. METHODS: Four teeth ground to dentin were randomly assigned to two groups. Group 1: Er,Cr:YSGG laser treatment; and Group 2: laser treatment while a 100 µm aperture stainless steel mesh was situated over the dentinal surface. RESULTS: Group 1 samples appeared rugged but relatively flat. Group 2 samples presented a surface with uniformly aligned craters ∼100 µm wide, 150 µm deep. CONCLUSIONS: Masking the dentinal surface with a stainless steel mesh during laser irradiation produces a surface texture that appears to facilitate mechanical retention.

Effect of Er,Cr:YSGG laser parameters on shear bond strength and microstructure of dentine.

OBJECTIVE: The objective of this study was to investigate the effect of different Er,Cr:YSGG laser parameters on the morphology of irradiated dentine and the shear bond strength between resin composites and irradiated dentine. MATERIALS AND METHODS: Dentine specimens prepared from extracted human third molars were randomly assigned to six groups, including one receiving phosphoric acid etching, and five others with different laser parameters: 5 W for 30 sec, 2.5 W for 30 sec, 2.5 W for 60 sec, 1.5 W for 30 sec, and 1.5 W for 100 sec. Surface morphology was examined using a scanning electron microscope (SEM). Average roughness (Ra) was determined with a profilometer. Bonding of resin composites to the dentine specimens was tested in shear mode. RESULTS: The dentine surfaces irradiated by the Er,Cr:YSGG laser showed a scaly and rugged appearance and open dentinal tubules without smear layer production. The 5-W-irradiated group had the highest roughness value (p < 0.05). One-way ANOVA revealed that the shear bond strength of resin composites to the laser-irradiated dentine ranged from 12.35-15.61 MPa, and was not significantly (p > 0.05) different from the bond strength seen in the acid-etched dentine of 19.06 MPa. However, the surface roughness of the laser-irradiated dentine was significantly (p < 0.05) higher than that of the acid-etched dentine. CONCLUSIONS: The 5-W power setting may be suitable for dental restoration applications in terms of shear bond strength and activation area.