Trueness of a device for intraoral scanning to capture the angle and distance between implants in edentulous mandibular arches.

STATEMENT OF PROBLEM: The digitalization of completely edentulous arches presents limitations because of the lack of anatomic structures for best-fit alignment during the image generation process of the scanner's software program. PURPOSE: The purpose of this clinical study was to evaluate a new device for intraoral scanning and to analyze its usefulness in capturing the 3-dimensional (3D) position of implants in edentulous mandibular arches. MATERIAL AND METHODS: The 3D positions of 40 implants in 10 participants with fixed interim mandibular prostheses were evaluated by comparing 3 scanning techniques. Images were generated in 2 experimental groups, with digital scan bodies (group SC) and with the scanning device (group SD) and in a control group (group CT) in which images were obtained by laboratory scanning of casts produced from splinted impression copings. The standard tessellation language (STL) files were superimposed by using a reverse engineering software program to measure the 3D coordinate system. Variations in implant linear displacements (Δx, Δy, and Δz), total 3D displacement (Δx2+Δy2+Δz2), and angle projections (ΔθXY, ΔθXZ, and ΔθYZ) were statistically analyzed (α=.05). The distances between the implants were also measured. The Spearman correlation coefficient (α=.05) was used to find the correlation between the 3D coordinates and the distances between the implants. RESULTS: Group SD had lower values for linear displacement than group SC; however, this difference was not statistically significant except for implant #2. The overall evaluation showed a significant difference with better accuracy for group SD. Concerning angular displacements, group SD showed lesser angular variation for the 3 projection planes. For the distances between the implants, significant differences were only observed for the "all" assessment in which group SD behaved similarly to group CT, while group SC showed the highest values (P<.05). No correlation was detected between the axes (x, y, and z) and the distances between the implants. CONCLUSIONS: The evaluated scanning device led to improved trueness for linear, angular displacements, and distances between implants in mandibular edentulous arches.

CAD/CAM-fabricated removable partial dentures: a case report.

AIM: The objective of this case study is to present the manufacturing process and delivery of a removable partial denture (RPD) using computer-aided design/computer-aided manufacturing (CAD/CAM) technology. MATERIALS AND METHODS: A 46-year-old female patient presented at the Federal University of Rio Grande do Norte complaining of the lack of retention in her mandibular RPD. After the design and preparation of the abutment teeth, further appointments were made. In the first appointment, intraoral scanning (IOS) with a Trios scanner was performed, followed by virtual planning of the framework. The RPD was then printed, invested, cast by induction, and polished. In the second appointment, the RPD was delivered. CONCLUSION: The technique proved to be efficient in terms of clinical time and sufficient for patient comfort and satisfaction.

Does a mandibular RDP and new maxillary CD improve masticatory efficiency and quality of life in patients with a mandibular Kennedy class I arch?

OBJECTIVES: To evaluate the change in masticatory efficiency and quality of life of patients treated with mandibular Kennedy class I removable partial dentures (RPDs) and maxillary complete dentures at the Department of Dentistry of the Federal University of Rio Grande do Norte. MATERIALS AND METHODS: A total of 33 Kennedy class I patients were rehabilitated with maxillary complete dentures, and mandibular RPDs were selected for this non-randomized prospective intervention study. The patients had a mean age of 59.1 years. Masticatory efficiency was evaluated by colorimetric assay using fuchsin capsules. The measurements were conducted at baseline and 2 and 6 months after prosthesis insertion. Quality of life was evaluated using the Oral Health Impact Profile (OHIP-14) at baseline and 6 months after denture insertion. The Kolmogorov-Smirnov normality test was applied. Masticatory efficiency was evaluated by repeated measures ANOVA. Oral health-related quality of life was compared using the paired t test. RESULTS: There was no statistically significant difference in masticatory efficiency after denture insertion (p = 0.101). Significant differences were found (p = 0.010) for oral health-related quality of life. A significant improvement in psychological discomfort (p < 0.01) and psychological disability (p < 0.01) was observed. Mean difference value (95 % confidence interval) was 6.8 (3.8 to 9.7) points, reflecting a low impact of oral health on quality of life, considering the 0-56 range of variation of the OHIP-14 and a Cohen's d of 1.13. CONCLUSION: According to the results of the present study, rehabilitation with Kennedy class I RPDs and complete dentures did not influence masticatory efficiency but improved oral health-related quality of life. CLINICAL RELEVANCE: The association between the patient's quality of life and the masticatory efficiency is important for treatment predictability.

Masticatory Performance And Impact On Oral Health-Related Quality Of Life In Patients Treated With Immediately Loaded Implant-Supported Prosthesis.

PURPOSE: To compare oral health-related quality of life (OHRQoL) and masticatory performance (MP) in patients treated with a mandibular complete denture (CD) and immediately loaded implant-supported prostheses (ISP). MATERIALS AND METHODS: Forty patients were divided into CD and ISP groups. Initially, all patients were treated with a mandibular CD. Then, 23 patients remained with a CD while 17 patients were treated with an ISP after wearing the CD for 3 months. OHRQoL was measured using the OHIP-EDENT questionnaire, and MP was evaluated by sieving. Data were recorded before treatment (T0) and after 3 months wearing the CD and ISP (T1). RESULTS: CD treatment did not affect OHRQoL and PM; however, patients treated with an ISP presented improvement in OHRQoL (P < .001) and MP (P < .001) with a high effect size (ES) (Cohen's d = 2.49 and 2.47, respectively). For intergroup analysis, ISP treatment presented improvement in OHRQoL and MP compared to CD treatment (P < 0.001) at T1 with a high ES (Cohen's d = 1.80 and 3.29, respectively). The correlation between MP and OHRQoL was positive only for psychologic discomfort in the CD group at T0 (P = .035), suggesting that poor MP increased psychologic discomfort. CONCLUSION: Converting a CD into an ISP had a positive impact on OHRQoL and MP with high ES.