Accuracy of implant placement in the posterior maxillary region depending on the alveolar residual bone height and sinus morphology: An in vitro study.

OBJECTIVES: The primary aim of this in vitro study was to assess the effect of alveolar residual bone height in the posterior maxilla on the accuracy of the final implant position via free-handed and static Computer-Assisted Implant Placement (sCAIP). The secondary aim was to evaluate the influence of the maxillary sinus morphology on the accuracy of final implant position. MATERIALS AND METHODS: Partially edentulous standardized maxillary models simulating three different residual bone heights and different sinus floor morphologies were investigated. One-hundred eighty equally distributed implants, which were placed either free-handed or sCAIP, constituted the study sample. 3D digital deviations were obtained by superimposing the post-surgical scans on the initial treatment plan. RESULTS: Angular and linear deviation assessment demonstrated higher implant position accuracy in the sCAIP group. sCAIP revealed similar outcomes independently of the alveolar bone height and sinus floor morphology. Contrarily, in the free-handed group, alveolar bone height and sinus morphology statistically affected the final implant position. Non-parametric three-way ANOVA showed significance for implant placement protocol (p < .0001) and alveolar bone height (p ≤ .02) when angular, and linear deviations were evaluated. Sinus morphology was statistically significantly associated with angular deviation (p = .0009). CONCLUSIONS: sCAIP demonstrated higher 3D implant position accuracy. Alveolar bone height (strongly) and sinus morphology are associated with the accuracy of final implant position when the free-handed implant protocol is followed. However, these anatomical factors did not affect final implant position during sCAIP.

Candida albicans adhesion on 3D-printed and thermopolymerizable polymethyl methacrylate for removable prostheses.

PURPOSE: To compare Candida albicans adhesion and quantify the biofilm formed on thermopolymerizable (T.PMMA) and 3D printing (3D.PMMA) polymethyl methacrylate through quantitative and qualitative analyses. METHODS: The specimens were made (n= 39/material) by conventional polymerization (T.PMMA) and designed in Autodesk Meshmixer software, followed by 3D printing (3D.PMMA) - CAD-CAM method. After the roughness standardization, the monospecies biofilm of C. albicans (ATCC 10231) was submitted to adhesion analysis, verifying the quantification and microbial load, in triplicate, by the methods of counting colony forming units (CFU/mL) and staining with crystal violet, followed by optical density reading, respectively. Qualitative analyses were performed by scanning electron microscopy to analyze the surface characteristics of the specimens and biofilm formed. The Mann-Whitney U test was used for comparisons between resins regarding the count of CFU/mL (log¹°+ 1) and optical density values (P≤ 0.05). RESULTS: T.PMMA (5.78 ± 0.43) had a CFU/mL count (P< 0.001) higher than 3D.PMMA (4.84 ± 0.39). There was a difference between C. albicans biofilm accumulation (P< 0.001), in which on T.PMMA (1.59 ± 0.31) was higher than 3D.PMMA (1.10 ± 0.14). The qualitative analyses corresponded to the quantitative ones and allowed the visualization of more porosities in T.PMMA. CLINICAL SIGNIFICANCE: The adhesion (microbial load and biofilm accumulation) of C. albicans was lower in the 3D printed polymethyl methacrylate when compared to the thermopolymerizable model.

Impact of the extension of the anterior-posterior spread on quality of life and satisfaction of patients treated with implant-retained mandibular overdentures - a randomized clinical trial.

OBJECTIVES: To compare the degree of satisfaction (SD) and the impact on oral health-related quality of life (OHRQoL) of edentulous patients treated with conventional complete dentures (CCDs) and mandibular overdentures (IODs) with a short anteroposterior spread (S-APS) or a large antero-posterior spread (L-APS). MATERIALS AND METHODS: Edentulous patients were treated with CCDs and subsequently randomly allocated to receive a bar clip mandibular overdenture retained by 2 interforaminal implants (Control) or 4 (Test: 2 additional implants distal to the mental foramen). The Oral Health Impact Profile Edent questionnaire (OHIP-20E) and the Visual Analogue Scale (VAS) were applied at a mean follow-up of 38.5 months to assess the impact on OHRQoL and DS, respectively. Comparisons between the type of prosthesis and the extension of the AP spread were made with Student's t test for paired samples and for independent samples, respectively, at a significance level of 5%. RESULTS: The IODs had significantly lower OHRQoL values ​​in the dimensions "functional limitation" (p=0.03), "physical pain" (p=0.02), "psychological discomfort" (p<0.01), "disability physical" (p<0.01) and "general score" (p<0.01) (n=20 patients). The IODs presented DS values ​​significantly for "aesthetics" (p=0.04), "stability" (p=0.03), "masticatory capacity" (p<0.01), "function" (p<0.01) and "oral condition" (p=0.03). The S-APS group (control) resulted in significantly lower values ​​in the dimensions "physical pain" (p<0.01) and "general score" (p<0.01) and no domain with statistical difference in the VAS scale. CONCLUSIONS: IODs significantly improved OHRQoL and DS. The increase in AP spread did not result in benefits for the patient's OHRQOL and DS in this clinical study. (Study Protocol Number: 1.452.492) CLINICAL SIGNIFICANCE: Implantology has experienced in the last 20 years a permanent evolution that aim at increasing predictability and improving long-term clinical performance. Placement of short implants distally to the mental foramen, for instance, and the resulting increase of the anterior-posterior spread, is a promising approach and is worthy of investigation.