A 3-year prospective cohort study on mandibular anterior cantilever restorations associated with screw-retained implant-supported prosthesis: An in vivo study

Implant abutment using hand drivers versus torque wrench

The most frequent instrument used to begin tightening screws is a manually regulated screwdriver. Regarding manually regulated screwdrivers, predicted margins of error vary between fifteen percent to forty eight percent. Mechanical Torque restricting devices can consistently produce the requisite torques. As a result, devices like wrenches are needed to achieve the desirable values of torque. Hence, the present study was designed to evaluate the torque difference between handheld drivers and torque wrench and thereby its effect on the internal threads of implant surface.120 blocks was prepared from an autopolymerizing type of acrylic material each with a dimension of 1 inch. The centre of each block was affixed with analogue of dental impalnts with dimensions of 3.5 mm width and 13 mm length. With 60 specimens each, these models were split into two categories: hand torque specimens category and torque wrench specimens category. A stereomicroscope was used to look at the implant analog's internal threading architecture at a magnification of 100. At the bottom and top, four threads were spaced apart by a certain amount. Biowizard software was used for the assessment, and the results were recorded. Threads on the internal surface of dental implants were produced once more following torquing the implant's impression, and the stereomicroscope was used to quantify the separation between the 4 threads. Statistics were used to correlate the readings. All study participants' hand torque as well as torque wrench measurements were documented and statistical analysis was performed on them. When there was statistical analysis of the measurements then it was observed that mean values of torque in specimens included category of manual torque application was found out to be 33.6 ± 6.510 Ncm. On the other hand the mean values of torque in specimens included in category of torque application by torque wrench were found out to be 33.57 ± 3.472 Ncm. The outcome showed operator heterogeneity for both categories and operator variance when using a manual driver to generate torque. One independent - sample t test was used to contrast the mean data between the two categories, and P< 0.05 was chosen to determine whether the intergroup difference was meaningful. Because the torque values obtained with hand tightening were uneven, it may be concluded that different levels of hand torquing skill caused the torque to fluctuate. The torque wrench device displayed the desired torque data in the range that the manufacturer had advised. However, utilising manual drivers and a mechanical torque instrument did not cause any modifications to thread on the internal surface, and it rarely underwent significant deformation during the preliminary tightening torque readings. Thus, given that manually hand regulated drivers create a range of torques, it may be inferred that the employment of mechanical torque restricting instruments should be required.

Assessment of the Survival of a Single Implant-Supported Cantilever Prosthesis in the Anterior Mandible

BACKGROUND

Implant dentistry has seen rapid and remarkable progress in recent years. The present study assessed the survival of a single implant-supported cantilever prosthesis (ISCP) in the anterior mandible.

MATERIALS AND METHODS

Sixty-four patients with missing mandibular anterior teeth of both genders were provided with a single implant and restored with cantilever screw-retained prosthesis. All were followed for 2.5 years for the implant and prosthetic success.

RESULTS

Age group of 20-30 years comprised 14 males and 10 females, 30-40 years had 10 males and eight females, 40-50 years had six males and seven females, and 50-60 years had four males and five females. The difference was nonsignificant (P > 0.05). A screw loosening was seen in total of 15 cases, in 1 at 12 months, 5 at 18 months, 2 at 24 months, and 7 at 30 months, and porcelain fracture was seen in total of eight cases, in 4 at 18 months, 1 at 24 months, and 3 at 30 months. The difference was statistically significant (P < 0.05).

CONCLUSION

Screw-retained ISCP developed complications such as screw loosening and porcelain fracture.