Purpose: This systematic review and meta-analysis aimed to evaluate the difference in longevity of tooth- supported ceramic prostheses designed by conventional and computer-aided design/computer-aided manufacturing (CAD/CAM) techniques.

Study selection: Two reviewers searched the Web of Science, PubMed, SCOPUS and LILACS databases between 1966 and October 2017. Clinical studies that compared the survival rate of CAD/CAM against conventional restorations were included.

Results: Eleven randomized controlled trials and three prospective studies were included, n = 14. Three types of tooth-supported restorations were searched in the included studies: single crown, multiple-unit and partial ceramic crown. The follow-up of patients in the studies ranged from 24 to 84 months. A total of 1209 restorations had been placed in 957 patients in the included trials, and failures were analyzed by type and material restoration. From a total of 72 restoration failures, the CAD/CAM system resulted in a 1.84 (IC95%: 1.28–2.63) higher risk than conventional manufacturing of ceramic restoration. Nevertheless, when drop-outs were included as a failure risk, the CAD/CAM system resulted in a risk of 1.32 (IC95%: 1.10–1.58). Multilevel analysis of tooth-supported ceramic restorations, considering dropouts as successes, resulted in rates of 1.48 and 2.62 failures per 100 restoration-years for the controls and CAD/CAM groups, respectively. Considering drop-outs as failures, we found rates of 4.23 and 5.88 failures per 100 restoration-years for the controls and CAD/CAM groups, respectively.

Conclusions: The meta-analysis results suggest that the longevity of a tooth-supported ceramic prostheses made by CAD/CAM manufacturing is lower than that of crowns mad by the conventional technique.

Purpose: Compare the accuracy of intraoral digital impression in full-arch implant-supported fixed dental prosthesis acquired with eight different intraoral scanner (Ios).

Methods: A polymethyl methacrylate acrylic model of an edentulous mandible with six scan-abutment was used as a master model and its dimensions measured with a coordinate measuring machine. Eight different Ios were used to generate digital impression: True Definition, Trios, Cerec Omnicam, 3D progress, CS3500, CS3600, Planmeca Emelard and Dental Wings. Fifteen digital impressions were made. A software called "Scan-abut" was developed to analyse and compare the digital impression with the master model, obtaining the scanning accuracy. The three-dimensional (3D) position and distance analysis were performed.

Results: Mean value of the 3D position analysis showed that the True Definition (31 μm ± 8 μm) and Trios (32 μm ± 5 μm) have the best performance of the group. The Cerec Omnicam (71 μm ± 55 μm), CS3600 (61 μm ± 14 μm) have an average performance. The CS3500 (107 μm ± 28 μm) and Planmeca Emelard (101 μm ± 38 μm) present a middle-low performance, while the 3D progress (344 μm ± 121 μm) and Dental Wings (148 μm ± 64 μm) show the low performance. The 3D distance analysis showed a good linear relationship between the errors and scan-abutment distance only with the True Definition and CS3600.

Conclusions: Not all scanners are suitable for digital impression in full-arch implant-supported fixed dental prosthesis and the weight of the output files is independent from the accuracy of the Ios.

Purpose: To assess the effect of the shooting angle variation on linear and planimetric measurements of the pink and white tissues on intraoral photographs.

Methods: From intraoral three-dimensional (3D) scans of the anterior region in 10 patients, ninety-nine two-dimensional (2D) "scan pictures" each were generated with different shooting angles, each varying in 5° horizontal and vertical increments. Eleven intraoral photographs of each patient and tooth site were taken free-hand: one shot at baseline and 5 shots after 3 and 6 months at slightly varying shooting angles. Papilla height (PH) and area (PA) and tooth crown area (TCA) were estimated on all photographs; the "best-match-to-baseline" photograph from those taken at 3 and 6 months was chosen by 6 evaluators.

Results: Within the first 10° of deviation from the baseline shooting angle, measurements on the 2D "scan pictures" distorted ≤0.5 mm for PH and ≥10% for PA and TCA. Compared to baseline, only 6 out of 100 photographs presented ≥0.5 mm difference in PH, none of the TCA measurements showed distortion ≥10%, and only in 4 instances a ≥10% distortion of the PA was observed. Poor to moderate inter- and intra-rater agreement in choosing the "best-match-to-baseline" photograph was found, but photographs with clinically relevant changes were only seldomly chosen.

Conclusions: Deviations in the shooting angle ≤10° from the baseline shot cause clinically negligible distortions in linear and planimetric measurements. Highly comparable intraoral photographs of the anterior maxillary teeth can be captured "free-hand" in slightly varying perspective, and then selecting the "best-match-to-baseline".

Purpose: This study investigated changes in food and nutrient intake after implant-supported fixed prosthesis treatment in patients with partial edentulous posterior regions.

Methods: This study included 30 patients who received implant treatment with fixed prostheses in the posterior region. Food and nutrient intake was evaluated using a brief self-administered diet history questionnaire at baseline and post-implant treatment, and the results were statistically analyzed.

Results: Treatment with implant-supported fixed prostheses in patients with posterior edentulous conditions tended to increase the amounts of soy products and vegetables consumed: in particular, intake of carrot and squash was significantly increased. The total energy, protein, lipid, and carbohydrate intakes were comparable between baseline and post-implant treatment. On the other hand, the vegetable protein, α-carotene, daidzein, and genistein intakes were significantly increased, and dietary fiber and β-carotene intakes tended to be increased in patients with implant-supported fixed prostheses.

Conclusions: Implant-supported fixed prostheses in patients with posterior edentulous conditions affected food intake, resulting in improved nutrient intake.

Purpose: To evaluate the clinicaland biological behavior of full coverage restorations on teeth prepared without finish line during a 4-year follow-up.

Methods: This prospective study included 149 teeth treated using biologically oriented preparation technique (BOPT). The sample (149 teeth) was divided into two groups: Seventy four teeth restored with crowns, and 75 teeth supporting fixed partial dentures (FPD). Restorations were fabricated with zirconium oxide cores and ceramic coverings. Patients attended regular annual check-ups when probe depth, presence of inflammation with bleeding on probing, presence of plaque, gingival thickness, marginal stability, biological or mechanical complications, and the patient' s level of satisfaction were registered over a 4-year follow-up.

Results: After the 4-year follow-up, 2.1% of teeth underwent increases in probing depth; 12% of the sample presented inflammation and bleeding on probing; 20% of the restored teeth presented plaque; gingival thickening increased a 32.5%; 98.6% of teeth presented marginal stability; the restoration survival rate was 96.6%, with 2% of biological complications and 1.4% of mechanical complications. General satisfaction score was 80.73.

Conclusions: Restorations placed on teeth prepared using BOPT present good periodontal behavior, increase of gingival thickening, and marginal stability over a 4-year follow-up. High survival rates after 4 years show that the technique produces predictable outcomes.

Clinical significance: The BOPT technique is a good treatment option in cases where replacement of an old restoration is required; presenting good periodontal behavior, gingival thickening, and marginal stability.

Purpose: The present cross-over study evaluated the masticatory function and maximum occlusal force of edentulous patients with complete dentures with bilateral balanced occlusion (BBO) and canine guidance (CG), with normal (NR) and resorbed mandibular ridges (RR).

Methods: Participants received new complete dentures and both occlusal concepts (BBO and CG) were applied for a period of 30 days each. The masticatory performance was evaluated with the sieving method; masticatory ability with a visual analog scale (VAS) and maximum occlusal force was assessed by means of a gnatodynamometer. Data were analyzed using repeated-measure ANOVA or Generalized Estimating Equations (GEEs), α = 0.05.

Results: Thirty women completed the trial. The height of mandibular ridge was significant for the masticatory performance (ANOVA, p < 0.001, NR = 46.35 ± 12.18%, RR = 30.39 ± 9.94%), regardless of the occlusion guidance. A significant effect of the occlusion guidance was observed for the maximum occlusal force (ANOVA, p = 0.021, CG = 31.99 ± 12.74 N, BBO = 28.37 ± 9.83 N). The occlusion guidance was not significant for the masticatory performance (ANOVA, p = 0.156) and the height of the mandibular ridge did not influence on the occlusal force (ANOVA, p = 0.060). The interaction of the factors (guidance × ridge) was not significant for masticatory performance (ANOVA, p = 0.184) and occlusal force (ANOVA, p = 0.236). The VAS scores showed a significant effect of the ridge on chewing of lettuce, resulting in greater ease (GEEs, p = 0.016) and chewing quality (GEE, p = 0.028) of this food for participants with resorbed ridges. Participants with CG reported greater ease of chewing fresh bread and beef, and expressed higher quality of chew raw carrot. Participants with CG and normal ridges exhibited the highest overall chewing ability, in comparison to BBO (Bonferroni, p < 0.05, CG = 91.9, BBO = 72.7).

Conclusions: CG represents a viable alternative to the BBO in complete dentures with satisfactory clinical results related to the self-perception of chewing and occlusal force.

Purpose: The study aimed to compare the mixing ability (MA), comminuting ability (CA), and maximum bite force (MBF) of single-implant overdentures (IODs) and clinically acceptable complete dentures (CDs) through a randomized crossover control trial.

Methods: New CDs were fabricated for 22 patients. One implant was inserted in the middle of the symphyseal region for each patient. The patients were randomly allocated into two groups: group IC received an IOD, whereas group CI received a CD, for 2 months; the treatments were interchanged for the next 2 months. The MA, CA, and MBF were evaluated with the old CDs, new CDs (at the end of CD treatment period), and IODs (at the end of IOD treatment period).

Results: The MA, CA, and MBF of the IODs were significantly higher than those of the old and new CDs (p < 0.01). New CDs only showed a significant improvement in MA (p < 0.05), while there were no significant differences in CA and MBF between the old and new CDs.

Conclusions: Compared with the CD, IOD is more effective in restoring the MA, CA, and MBF of edentulous mandibles.

Purpose: The purpose of this study was to evaluate the trueness and precision of eight different extraoral laboratory scanners using three-dimensional (3D) analysis method.

Method: An arch-shaped master model was designed with a computer software (Rapidform XOR2) and manufactured with a 3D printer (Projet 3510 MP). Then the master model was digitized with an industrial 3D scanner (ATOS Core 200). With each scanner master model was scanned ten times and stereolithography (.stl) data were imported into 3D analysis software (Geomagic Control). Accuracy was determined with evaluating trueness and precision.

Results: Trueness of the scanners were 27.5 μm for 7 series; 30.9 μm for D640; 26.8 μm for D710; 33.3 μm for Activity 102; 32.4 μm for Tizian Smart-Scan; 21.6 μm for NeWay; 26.1 μm for inEOS X5 and 17,47 μm for D2000. 28.2 μm for laser; 32.9 μm for white light and 21.7 μm for blue light scanners. Significant differences were found between scanners (p <.001), (p <.001). Precision of the scanners were 30.1 μm for 7 series; 31.7 μm for D640; 26.3 μm for D710; 22.7 μm for Activity 102; 25.1 μm for Tizian Smart-Scan; 15.7 μm for NeWay; 26.1 μm for inEOS X5; 16.6 μm for D2000. 29.2 μm for laser; 24.4 μm for white light and 19.2 μm for blue light scanners. Significant differences were found between scanners (p <.001), (p =.027).

Conclusions: The systems that had the best combination of trueness and precision for complete-arch scanning were D2000 and NeWay. Scanners using blue-light showed more accurate results than the white-light and laser scanners.

Purpose: To assess the clinical performance of the complete rehabilitation of a series of patients with bruxism treated by teeth- and implant-supported veneered and non-veneered zirconia restorations with an increased vertical dimension of occlusion (VDO).

Methods: Ten patients with bruxism, aged 62–70 years, were treated with 108 veneered and 142 nonveneered zirconia restorations and attended the recall appointment. The mean observation period was 28.2 (±16.8) months. The patients were identified from records, and clinical details were retrieved from their files. In the recall appointment, the restorations were evaluated using modified California Dental Association (CDA) criteria. The periodontal probing depth, bleeding index, presence of caries and implant survival and success rate were recorded.

Results: No biological complications were recorded for any restorations. The success and survival rate of all implants was 100%. The overall mean survival and success rate of all restorations was 99.6%. In the veneered group, the predominant complication was minor veneer chipping (13.9%) on the incisal edge, which required only polishing (grade 1); in the non-veneered group, the predominant failure was open proximal contacts between the implant restoration and adjacent teeth (9%); only one implant restoration needed repair. One restoration was replaced due to a horizontal tooth fracture.

Conclusions: Within the limitations of this study, we conclude that the survival and success rate of monolithic zirconia restorations installed in patients with bruxism was excellent, although the veneered zirconia restorations showed a high rate of minor veneer chipping, which required only polishing.

Purpose: The objective of this study was to evaluate the suitability of monolithic zirconia crowns (MZC) as abutment teeth of Akers clasps on removable partial dentures (RPD) by determining the change in retentive force after repetitive insertion/removal test.

Methods: MZC and silver palladium copper alloy (Ag–Pd) full-metal crowns (FMC) for the mandibular second premolar were fabricated. Resin patterns of Akers clasps made with a 3D printer were casted with Ag–Pd or cobalt chromium alloy (Co–Cr). Clasp retentive force was measured with combinations of the crown and clasp materials. After measuring the initial retentive force of the clasp, repetitive insertion/removal test was carried out. The surface of the crown before and after the test was observed with an optical microscope and a scanning electron microscope; some specimens were subjected to element analysis by an electron probe microanalyzer.

Results: The initial retentive force of the Co–Cr clasp was greater than the Ag–Pd clasp for both MZC and FMC. Clasp retentive force decreased with increasing number of insertion/removal cycles, and least reduction in force was observed for the Ag–Pd clasp on MZC. Wear marks were detected where FMC contacted the clasp. Discoloration of MZC due to wear of the Co–Cr clasp was observed.

Conclusions: When repetitive insertion/removal of the clasp was performed on MZC, retentive force decreased depending on clasp materials. However, the amount of decrease in retentive force was comparable or small compared to conventional FMC. As a result, it was suggested that MZC could be used on abutment tooth for RPD.

Purpose: Much research has been invested in determining the effects of postoperative loading of implants and whether this loading contributes to implant failure, but the issue remains controversial. The present study aimed to elucidate whether cyclic lateral loading of an implant causes bone resorption or bone formation at various loading magnitudes, using a finite element method (FEM) and peri-implant morphologic and morphometric analyses.

Methods: An FEM model was created using Digital Imaging and Communications in Medicine (DICOM) data of rabbit tibia. For the animal study, implants were inserted into rabbit tibia and, after osseointegration, were subjected to lateral cyclic loading of 20N, 40N or 60N.

Results: Bone-implant contact was significantly higher in both 40N and 60N groups. Boneâ abutment contact (BAC) was extraordinarily observed in all experimental groups. Bone height was higher than the implant platform level at higher levels of loading (60 N). Among the three experimental groups, those receiving 40 N loading had the highest bone height and BAC. Larger BAC values were observed on the compressive side than the tensile side.

Conclusions: Peri-implant bone formation was enhanced with increased loading, with bone formation predominantly on the compressive side. BAC was highest in the 40 N group, implying existence of a loading threshold for peri-implant bone formation and resorption.