Impression techniques should precisely represent the 3-dimensional status of implants to allow for the fabrication of passively fitting prostheses and subsequently the elimination of strain on supporting implant components and surrounding bone. The aim of this study was to compare the accuracy of an abutment level impression method with that of an implant level (direct and indirect) impression method using polyether impression material to obtain precise definitive casts and prostheses. A reference acrylic resin dentoform with 2 internal connection implants (Implantium) was made. A total of 21 medium-consistency polyether impressions of the dentoform, including 7 direct implant level, 7 indirect implant level, and 7 abutment level (after 2 straight abutments were secured), were made. Impressions were poured with American Dental Association (ADA) type IV stone, and the positional accuracy of the implant replica heads and abutment analogs in each dimension of x-, y-, and z-axes, as well as angular displacement (Δθ), was evaluated using a coordinate measuring machine. Noble alloy 3-unit castings were fabricated and seated on the abutments in 3 groups; marginal discrepancies were measured at 4 points between prostheses and abutments. Data were analyzed using Mann-Whitney U test, 1-way analysis of variance (ANOVA), and Kruskal-Wallis tests. In comparisons of different impression techniques, only significant statistical Δθ differences were noted between the abutment level method and other techniques (P < .001). Results of this study reveal that although the implant level impression method could better transfer the angular position of the implants (Δθ), the impression method could not affect Δy, Δx, and Δz coordinates of the implants or marginal discrepancy of the 3-unit fixed partial dentures (FPD).

Purpose: This study aimed to evaluate treatment outcomes of mandibular overdentures retained by two different mini-implant systems with ball attachments under a two-step immediate loading protocol.

Materials and methods: This clinical trial investigated treatment outcomes of mandibular mini-implant overdentures in 45 edentulous patients. MDI implants (3M ESPE) and SlimLine implants (Dentium) were randomly selected for placement in the anterior mandible in each group (MDI = 21; SlimLine = 24) with a flapless surgical approach. The side of the tissue in the region of the complete mandibular denture where mini-implants were placed was immediately relined with soft reliner (COE-SOFT). The female components were attached on the dentures 2 months after implant placement. Clinical and radiographic data were collected during follow-up. Statistical analyses were performed using SPSS software version 22.0 (α = .05).

Results: A total of 177 mini-implants were inserted in the anterior mandibles of 45 totally edentulous patients. There were five implant failures (97.2% success rate) and no significant differences between the two implant groups. Most mini-implants showed stable initial Periotest values (a mean ± standard deviation of 1.03 ± 3.65 mm) and a mean marginal bone loss of 0.50 ± 0.75 mm at 12 months. Multiple regression analysis revealed that implants ≤ 2.4 mm in diameter had higher Periotest values than those ≥2.8 mm. Intial Periotest values significantly influenced implant failure (P < .05).

Conclusion: There were no significant differences in treatment outcomes between patients treated with MDI or SlimLine implants. Mini-implants with wider diameters showed higher initial stability than those with narrow diameters, which may influence implant survival.

Purpose: Many experts have proposed the treatment of titanium surfaces with plastic or nonmetal tips to prevent damage to implant surfaces by metal instruments during professional cleaning. It is also known that any material that is softer than titanium may leave remnants of itself on the treated surface. The aim of this study was to quantify the surface area covered by plastic remnants after instrumentation with various plastic instruments and to evaluate the efficacy of the removal of these remnants by confocal microscopy.

Materials and methods: Twenty-seven rough-surfaced titanium disks were used for quantification of plastic remnants. Nine disks each were cleaned with (1) a plastic tip on ultrasonic scaler A, (2) a carbon tip on ultrasonic scaler B, or (3) a plastic curette. Three disks from each group were cleaned with a three-way syringe for 10 seconds, and three other disks were cleaned with 0.2% chlorhexidine-soaked cotton pellets. Images were obtained at random areas on each disk with a confocal microscope, and a digital image analysis program was used to quantify the area with autofluorescence.

Results: Approximately 10% to 20% of the surface was covered with plastic remnants of the instrument, irrespective of the instrument used. These remnants were not removed with a three-way syringe or chlorhexidine-soaked cotton pellets.

Conclusion: Plastic remnants remained after instrumentation, regardless of the instrument used. Moreover, the study highlighted the difficulty of removing all remnants with water spray or a chlorhexidine-soaked cotton pellet. This study suggests that confocal microscopy is a reproducible method for quantification that may be applied for future comparisons of methods to remove plastic residue. Further research is warranted to evaluate the biologic effects of plastic remnants.