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OBJECTIVE To investigate the clinical performance of monolithic zirconia implant crowns as compared to porcelain-fused-to-metal (PFM) implant crowns. MATERIALS AND METHODS Seventy-six healthy patients received reduced diameter implants in the molar region. Following random allocation, either a monolithic zirconia crown (Mono-ZrO$_{2}$ ) or a (PFM) was inserted. Crown and implant survival rates, modified USPHS criteria, clinical measurements, and interproximal marginal bone level (MBL) were assessed at crown delivery (baseline, BL) and at the 1-year follow-up (1y-FU). Data were analyzed descriptively. Fisher's exact test and Wilcoxon rank sum test were applied for statistical analysis. The level of statistical significance was set at p

Peri-implant bone dehiscences were grafted either with deproteinized bovine bone mineral (DBBM) block or with particulate DBBM, both covered with a collagen membrane and stabilized with resorbable pins. After 6 months, 17 biopsy samples were included for histologic assessment. Block and particulate DBBM rendered successful tissue integration. Particulate DBBM showed a median of 25.2% of new bone and 31.3% of bone substitute. In the block group, there was a median of 11.5% of new bone and 36.0% of bone substitute. When interpreting the discrepancy in new bone between the groups, the difference in the size of the augmented hard tissue needs to be taken into account.

To test whether soft-type block bone substitute used for guided bone regeneration (GBR) of peri-implant defects leads to a different dimension of the augmented hard tissue than particulate bone substitute.In 40 patients, 40 two-piece dental implants were placed2 months after tooth extraction. Following random allocation, 20 peri-implant bone dehiscences were grafted with a soft-type block made of synthetic biphasic calcium phosphate (BCP) + collagen and 20 bone dehiscences with particulate BCP. All the sites were covered with a collagen membrane stabilized with titanium pins. Immediately after wound closure and after 6 months, the horizontal dimension (HD) of the augmented hard tissue was measured at the level of implant shoulder using cone beam computed tomography. During re-entry at 6 months, the defect fill was clinically assessed.At 6 months, the median HD measured 1.15 mm (mean: 1.31 mm) in the soft-block group and 0.93 mm (mean: 1.05 mm) in the particulate group (p = .6). At 6 months, 7.1% of contained defects and 61.9% of non-contained defects showed an incomplete vertical defect fill.Soft-type block of BCP + collagen used for GBR of peri-implant defects did not differ from particulate BCP regarding the dimension of the augmented hard tissue after 6 months of healing.

The aim of this study was to identify the additional effects of collagen membrane (CM) and of synthetic bone substitute (BS) on lateral bone augmentation of chronic peri-implant defect with titanium mesh (TM).Atrophic alveolar ridge was induced in six canine mandibles, and 5 peri-implant defects were achieved in each hemi-mandible. Bone augmentation was attempted using the following randomly allocated modalities: (1) Control: no treatment, (2) TM only group: blood clot covered by TM, (3) TM+BS group: BS covered by TM, (4) TM+CM group: blood clot covered by TM and CM, and (5) TM+BS+CM group: BS covered by TM and CM. After 16 weeks of submerged healing, micro-CT and histomorphometric analyses were performed.TM exposure occurred in one case in the TM only group, one case in the TM+CM group, and two cases in the TM+BS+CM group. Histologically, pseudo-periosteum was observed along the inner and outer surfaces of TM, and the directions of the collagen fiber within the pseudo-periosteum differed according to the additional use of CM. In general, the TM only group rendered higher values in vertical defect fill and dimension of the augmented hard tissue in comparison with the other treatment groups.Due to the small sample size, this pilot study remains inconclusive. Within the limitations of the study, the use of CM and/or BS did not appear to have an additional benefit on lateral bone augmentation of peri-implant defect with TM.

STATEMENT OF PROBLEM Clinical trials are needed to evaluate the digital and conventional fabrication technology for providing fixed partial dentures (FPDs). PURPOSE The purpose of the second part of this clinical study was to compare the laboratory production time for tooth-supported, 3-unit FPDs by means of computer-aided design and computer-aided manufacturing (CAD-CAM) systems and a conventional workflow. In addition, the quality of the 3-unit framework of each treatment group was evaluated clinically. MATERIAL AND METHODS For each of 10 participants, a 3-unit FPD was fabricated. Zirconia was used as the framework material in the CAD-CAM systems and included Lava C.O.S. CAD software (3M) and centralized CAM (group L); CARES CAD software (Institut Straumann AG) and centralized CAM (group iT); and CEREC Connect CAD software (Dentsply Sirona) and centralized CAM (group C). The noble metal framework in the conventional workflow (group K) was fabricated by means of the traditional lost-wax technique. All frameworks were evaluated clinically before veneering. The time for the fabrication of the cast, the 3-unit framework, and the veneering process was recorded. In addition, chairside time during the clinical appointment for the evaluation of the framework was recorded. The paired Wilcoxon test together with appropriate Bonferroni correction was applied to detect differences among treatment groups (α=.05). RESULTS The total effective working time (mean ±standard deviation) for the dental technician was 220 ±29 minutes in group L, 217 ±23 minutes in group iT, 262 ±22 minutes in group C, and 370 ±34 minutes in group K. The dental technician spent significantly more time in the conventional workflow than in the digital workflow, independent of the CAD-CAM systems used (P

STATEMENT OF PROBLEM Clinical trials are needed to evaluate digital and conventional technologies for providing fixed partial dentures. PURPOSE The purpose of the first part of this clinical study was to test whether complete-arch digital scans were similar to or better than complete-arch conventional impressions regarding time efficiency and participant and clinician perceptions. MATERIAL AND METHODS Ten participants in need of a posterior tooth-supported 3-unit fixed partial denture were included. Three intraoral digital scanners and subsequent workflows (Lava C.O.S.; 3M [Lava], iTero; Align Technology Inc [iTero], Cerec Bluecam; Dentsply Sirona [Cerec]) were compared with the conventional impression method using polyether (Permadyne; 3M) and the conventional workflow. A computer-generated randomization list was used to determine the sequence of the tested impression procedures for each participant. The time needed for the impression procedures, including the occlusal registration, was assessed. In addition, the participant and clinician perceptions of the comfort and difficulty of the impression were rated by means of visual analog scales. Data were analyzed with the nonparametric paired Wilcoxon test together with an appropriate Bonferroni correction to detect differences among the impression systems (α=.05). RESULTS The total time for the complete-arch impressions, including the preparation (powdering) and the occlusal registration, was shorter for the conventional impression than for the digital scans (Lava 1091 ±523 seconds, iTero 1313 ±418 seconds, Cerec 1702 ±558 seconds, conventional 658 ±181 seconds). The difference was statistically significant for 2 of the 3 digital scanners (iTero P=.001, Cerec P

AIM To investigate new bone (NB) formation by using bone-block substitute materials with/without recombinant human bone morphogenetic protein-2 (rhBMP-2). MATERIALS AND METHODS Three synthetic bone-block substitute materials [biphasic calcium phosphate (BCP); nanostructured hydroxyapatite (NH); 3D-printed tricalcium phosphate/hydroxyapatite (3DP)] and one xenogeneic deproteinized bovine bone mineral (DBBM) block substitute were affixed to rabbit calvarium using osteosynthesis screws, either with rhBMP-2 (n = 12) or without rhBMP-2 (n = 16). At 2 or 12 weeks (n = 6 with rhBMP-2 and n = 8 without rhBMP-2 for each week), histologic, histomorphometric and microcomputed tomography analyses were performed. RESULTS The application of rhBMP-2 increased NB formation in all experimental groups at both weeks. DBBM resulted in a greater area of NB compared with synthetic blocks either with or without rhBMP-2 at 2 weeks (2.8 ± 0.9 vs. 1.4 ± 0.5-1.9 ± 1.4 mm$^{2}$ ; 1.4 ± 1.0 vs. 0.6 ± 0.3-0.9 ± 0.5 mm$^{2}$ ) and without rhBMP-2 at 12 weeks (3.0 ± 0.8 vs. 1.7 ± 0.7-2.6 ± 1.5 mm$^{2}$ ) (p > 0.05). NB formation did not differ significantly for DBBM and the three types of synthetic block with rhBMP-2 at 12 weeks (4.5 ± 2.0 vs. 3.8 ± 0.7-5.1 ± 1.1 mm$^{2}$ ; p > 0.05). CONCLUSIONS rhBMP-2 enhanced NB in all blocks. DBBM blocks yielded more NB than synthetic blocks without rhBMP-2. The application of rhBMP-2 appears to compensate for differences in late healing.

This study quantified the strain development after inserting implant‐borne fixed dental prosthesis (FDP) to various implant–abutment joints. Two bone‐level implants (∅ = 4.1 mm, RC, SLA 10 mm, Ti, Straumann) were inserted in polyurethane models (N = 3) in the area of tooth nos 44 and 47. Four‐unit veneered zirconium dioxide FDPs (n = 2) were fabricated, one of which was fixed on engaging (E; RC Variobase, ∅ = 4.5 mm, H = 3.5 mm) and the other on non‐engaging (NE) abutments (RC Variobase, ∅ = 4.5 mm, H = 5.5 mm). One strain gauge was bonded to the occlusal surface of pontic no. 46 on the FDP and the other two on the polyurethane model. Before (baseline) and after torque (35 Ncm), strain values were recorded three times. Data were analyzed using Kruskal–Wallis and Mann–Whitney U tests (α = 0.05). Mean strain values presented significant increase after torque for both E and NE implant–abutment connection type (baseline: E = 4.33 ± 4.38; NE = 4.85 ± 4.85; torque: E = 196.56 ± 188.02; NE = 275.63 ± 407.7; p

The objective of this study was to test whether or not soft tissue augmentation with a volume-stable collagen matrix (VCMX) leads to similar volume gain around dental implants compared to autogenous subepithelial connective tissue graft (SCTG). In 12 adult beagle dogs, immediate implants were placed with simultaneous guided bone regeneration. After 25–45 weeks, soft tissue augmentation was randomly performed using VCMX, SCTG, or a sham-operated control. Impressions were taken pre-op and post-op (tissue augmentation) and again at sacrifice after healing periods of 4, 8, and 24 weeks. They were then digitized to allow for superimposition. Values of linear and volumetric changes were calculated. The median increase (pre-op to post-op) in buccal volume measured 0.92 mm for VCMX, 1.47 mm for SCTG, and 0.24 mm for SH. The values (pre-op to sacrifice) were − 0.25 mm for VCMX, 0.52 mm for SCTG, and − 0.06 mm for group SH. The median ridge width 2 mm below the crest measured − 0.26 mm for VCMX, 0.53 mm for SCTG, and − 0.15 mm for SH (pre-op to sacrifice). Volume augmentation using VCMX and SCTG resulted in an increase in ridge dimension (pre- to post-op). During the follow-up, the volume decreased in all three groups to a level close to the situation prior to surgery. Soft tissue volume augmentation around dental implants is usually performed using the patient’s own tissue. This therapy is associated with an increased morbidity due to a second surgical site. Soft tissue volume at implant sites can be augmented using VCMX and SCTG. The gain on top of the ridge appears not to be stable during the follow-up in both groups.

Aim To test whether guided bone regeneration (GBR) of peri-implant defects at zirconia (ZrO2) implants differs from GBR at titanium (Ti) implants regarding the bone integration of the implant and of the grafting material. Materials and methods Maxillary premolars and molars were extracted in seven dogs. After 5 months, four semi-saddle bone defects were created in each maxilla. Implant placement and simultaneous GBR were performed using the following randomly assigned modalities: (1) ZrO2 implant + deproteinized bovine bone mineral (DBBM) granules + a collagen membrane (CM), (2) ZrO2 implant + DBBM with 10% collagen matrix + CM, (3) ZrO2 implant + DBBM block + CM, and (4) Ti implant + DBBM granules + CM. After 3 months, one central histological section of each site was prepared. Histomorphometrical assessments were performed evaluating the augmented area (AA) within the former bone defect (primary outcome), the area of new bone (NB), bone substitute (BS), and non-mineralized tissue (NMT) within AA in mm2. In addition, the distance between the most coronal bone-to-implant contact and the margin of the former bone defect (fBIC-DEF), and the bone-to-implant contact fraction (BIC) were measured in mm. Results AA measured 8.6 ± 4.0 mm2 for ZrO2 implant + DBBM granules, 4.7 ± 1.6 mm2 for ZrO2 implant + DBBM-collagen, 5.1 ± 1.9 mm2 for ZrO2 implant + DBBM block, and 7.6 ± 2.8 mm2 for Ti implant + DBBM granules. There were no statistically significant differences between the treatment modalities (P > 0.05). NB reached 2.0 ± 1.7 mm2 for ZrO2 implant + DBBM granules, 0.9 ± 0.9 mm2 for ZrO2 implant + DBBM-collagen, 2.1 ± 0.9 mm2 for ZrO2 implant + DBBM block, and 0.8 ± 0.6 mm2 for Ti implant + DBBM granules. fBIC-DEF amounted to 2.1 ± 1.7 mm2 for ZrO2 implant + DBBM granules, to 2.7 ± 1.1 mm2 for ZrO2 implant + DBBM-collagen, to 2.9 ± 1.2 mm2 for ZrO2 implant + DBBM block, and to 3.4 ± 0.4 mm2 for Ti implant + DBBM granules. BIC measured 70 ± 19% for ZrO2 implant + DBBM granules, 69 ± 22% for ZrO2 implant + DBBM-collagen, 77 ± 30% for ZrO2 implant + DBBM block, and 66 ± 27% for Ti implant + DBBM granules. Conclusions The findings of the present pilot study suggest that zirconia and titanium implants grafted with DBBM granules and covered with a collagen membrane do not perform differently regarding the augmented ridge contour, the NB formation, and the implant osseointegration.

To test whether or not a one- (S1) and a two-piece (S2) dental implant systems render the same biological, technical, and esthetic outcomes regarding implants and implant-supported reconstructions over an observation period of 4 to 6 years.Sixty patients were randomly assigned to receive S1 or S2 implants. The implants were restored with either fixed or removable prostheses. The insertion of the final reconstruction was chosen as baseline. One-year and 4- to 6-year (FU-5) measurements included biological (e.g. marginal bone level, probing pocket depth, peri-implant mucositis, and peri-implantitis), technical (e.g. fracture or loosening of prosthetic screws, fracture or loosening of abutments, fracture of framework, and/or veneering ceramic (minor, major), loss of retention for cemented restorations), and esthetic parameters (visibility of the crown margin, shimmering of the implant through the mucosa, the level of the facial margo mucosae compared to the contralateral tooth or implant site and the modified papilla index) for implants and reconstructions. Survival and success rates of implants and reconstructions were calculated. Because of the asymmetric data distributions, nonparametric statistical methods were applied.The implant-based analysis revealed a cumulative implant survival rate of 97.9% (S1: 96.6%; S2: 98.9%) at FU-5. The median marginal bone level for group S1 changed from 0.51 mm at baseline to 0.49 mm at FU-5 and for group S2 from 1.02 mm to 1.35 mm (P 0.001). Patient-level analyses demonstrated a frequency of peri-implant mucositis of 7.7% (S1) and 10.0% (S2) and for peri-implantitis of 7.7% (S1) and 13.3% (S2) at FU-5. The patient-based cumulative implant survival rate was 94.6% (S1: 92.3%; S2: 96.7%). The overall patient-based biological complication rate amounted to 15.4% (S1) and to 23.3% (S2) (P = 0.517), whereas the overall technical complication rates were 30.8% (S1) and 13.3% (S2) (P = 0.349). The prosthetic survival rates were 93.1% for S1 and 100% for S2 (P 0.05).Both implant systems reveal high survival rates on the implant and prosthetic level. Apart from marginal bone-level changes, biological and technical outcomes did not reveal significant differences between the two implant systems.

Aim To assess (i) bone regeneration around implants placed early in sites with or without ridge preservation and (ii) if the bone substitute material (DBBM-C) has to be removed at implant placement. Materials and methods In eight beagle dogs, three sites were randomly assigned to ridge preservation (DBBM-C plus collagen matrix (CMX)) (two sites; RP) or spontaneous healing (1 site; SH). Four weeks later, in one of the RP sites, dental implants were placed without removing the DBBM-C (RP1), whereas in RP2 and SH sites all non-integrated DBBM-C and/or granulation tissue were removed before implant placement and concomitant GBR. Histomorphometric outcomes were assessed at 4 and 12 weeks. Results The median buccal fBIC (first bone-to-implant contact) was located more apical in groups RP1: 1.34 mm (0.09; 2.96) and RP2: 1.41 mm (0.54; 2.72) than in group SH: 0.79 mm (0.26; 1.50) (p = 0.452) at 4 weeks. At 12 weeks, median buccal fBIC values were for RP1: 0.88 mm (0.00; 2.33), for RP2: 0.16 mm (0.00; 1.33) and for SH: 0.00 mm (0.00; 0.98) (p = 0.362). BIC values increased over 12 weeks in all groups. Conclusions Ridge preservation followed by early implant placement led to higher BIC values at 12 than at 4 weeks. There is no need to remove the biomaterial at implant placement to ensure osseointegration. No relevant differences were observed between the three groups for any outcome measure.

Aim To test whether implants placed with simultaneous guided bone regeneration (GBR) differ from implants placed without GBR regarding survival rate, interproximal marginal bone level (MBL), and dimensions of buccal bone and mucosa. Material and Methods Twenty-three patients treated 15 years earlier were included. Machined implants had been inserted following one of the two procedures: (i) with simultaneous GBR, which involved grafting with particulate deproteinized bovine bone mineral (DBBM), autogenous bone (AB), or a mixture of the two and defect covering with a native collagen membrane (CM) (GBR group) and (ii) standard implant placement without GBR (control group). One GBR and one control implant in each patient were selected for analysis. At 15 years, the dimensions of buccal bone and mucosa were measured with cone beam computed tomography. The interproximal MBL was evaluated at 5 and 15 years on periapical radiographs. Results The 15-year survival rate amounted to 95.6% for GBR implants and to 94.1% for control implants. At 15 years, interproximal MBL measured 1.44 ± 0.84 mm for the GBR group and 1.69 ± 0.84 mm for the control group. From the 5- to the 15-year examination, the loss of interproximal MBL reached 0.23 ± 0.70 mm for the GBR group and 0.28 ± 0.63 mm for the control group. At 15 years, buccal MBL measured 1.98 ± 0.98 mm for GBR implants and 2.19 ± 1.29 mm for control implants. None of these values reached statistical significant differences between the groups. In cases in which GBR involved grafting with DBBM, GBR implants achieved approximately 0.3–0.4 mm higher mean values in buccal bone dimensions and mucosal level in comparison to control implants. In contrast, when GBR was performed by grafting with AB without DBBM, implants rendered less favourable results in buccal bone and mucosa dimensions than the control implants. Conclusions Implants placed with simultaneous GBR using particulate DBBM and/or AB in combination with CM did not significantly differ from implants completely placed into pristine bone with respect to 15-year implant survival, interproximal bone levels, and dimensions of buccal bone and mucosa. The machined-surface implants placed both into native bone and sites augmented by GBR exhibited stable interproximal bone levels.

OBJECTIVES To test whether block bone substitute used for guided bone regeneration (GBR) of peri-implant defects leads to different thickness of the augmented hard tissue than particulate bone substitute. MATERIAL AND METHODS In 24 patients, 24 two-piece dental implants were placed >4 months after tooth extraction. Following random allocation, 12 peri-implant bone dehiscences were grafted with an individually shaped block of deproteinized bovine-derived bone mineral (DBBM) and 12 bone dehiscences with particulate DBBM. All the sites were covered with a collagen membrane stabilized with resorbable pins. Immediately after wound closure and after 6 months, the horizontal thickness (HT) of the augmented hard tissue was measured at the level of implant shoulder using cone beam-computed tomography. RESULTS After wound closure, the median HT measured 3.35 mm (mean: 3.38) in the block group and 2.85 mm (mean: 2.73) in the particulate group. At 6 months, the median HT decreased to 2.90 mm (mean: 2.71) in the block group and to 0.2 mm (mean: 0.52) in the particulate group. This difference was statistically significant (p

OBJECTIVES To test whether the load-bearing capacity of occlusal veneers made of ceramic or hybrid materials bonded to dentin does differ from those of porcelain-fused-to metal or lithium disilicate glass ceramic crowns. MATERIAL AND METHODS In 80 human molars, occlusal tooth substance was removed so that the defects extended into dentin, simulating defects caused by attrition/erosion. Restorations at a standardized thickness of either 0.5 mm or 1.0 mm were digitally designed. For both thicknesses, 4 test groups (n = 10 per group) were defined, each including a different restorative material: "0.5-ZIR": 0.5 mm thick zirconia (Vita YZ HT); "1.0-ZIR": 1.0 mm thick zirconia (Vita YZ HT); "0.5-LDC": 0.5 mm thick lithium disilicate ceramic (IPS e.max Press); "1.0-LDC": 1.0 mm thick lithium disilicate ceramic (IPS e.max Press); "0.5-HYC": 0.5 mm thick PICN (Vita Enamic); "1.0-HYC": 1.0 mm thick PICN (Vita Enamic); "0.5-COC": 0.5 mm thick tooth shaded resin composite (Lava Ultimate) and "1.0-COC": 1.0 mm thick tooth shaded resin composite (Lava Ultimate). Consecutively, the specimens were thermo-mechanically aged and then loaded until fracture. The load-bearing capacities (F) between the groups were statistically compared using the Kruskal-Wallis test (p 0.05). The median F values of the 1.0 mm thick restorations were: 2'489 N in the group 1.0-ZIR, 1'864 N in the group 1.0-LDC, 2'485 N in the group 1.0-HYC and 2'479 N in the group 1.0-COC. With CLD as the control group, a significant difference between zirconia and lithium-disilicate was found for the 0.5 (p = 0.0017) and 1.0 mm (p = 0.0320) thick specimens. Comparing the 0.5 mm thick specimens with CLD as the control, a significant difference was found between 0.5-HYC and 0.5-LDC (p = 0.0017). With PFM as the control, the comparison of lithium disilicate and zirconia was statistically significant for both thicknesses (p = 0.0009 for the 0.5 mm thick specimens; p = 0.0074 for the 1.0 mm thick specimens). In addition, with PFM as control group, significant differences were seen between 0.5-LDC and all other groups with restorations in 0.5 mm thickness (p = 0.0017). CONCLUSIONS Regarding their maximum load-bearing capacity, minimally invasive occlusal veneers made of ceramic, hybrid materials or polymeric materials can be applied to correct occlusal tooth wear with exposed dentin and thus replace conventional crown restorations in cases of normally expected intraoral bite forces.

Statement of problem Studies evaluating the trueness of intraoral scanners (IOSs) at anatomic locations within an intracoronal preparation are lacking. Purpose The purpose of this in vitro study was to evaluate the trueness of digital scans obtained by IOSs at the margin and intaglio surfaces of intracoronal preparations. Material and methods Six IOSs (CEREC Omnicam, E4D, FastScan, iTero, TRIOS, Zfx IntraScan) were used to obtain digital scans of various intracoronal preparations. Standard tessellation language (STL) data sets obtained from a reference scanner and each IOS were superimposed, and the deviation of the digital casts was assessed at multiple measuring points along the margin and intaglio surfaces of each preparation. The Kruskal–Wallis test and multiple Mann–Whitney tests were used to detect differences in trueness (α=.05). Results The overall median trueness values were lowest for TRIOS (23.9 μm), followed by Zfx IntraScan (24.6 μm), iTero (25.4 μm), FastScan (26.1 μm), CEREC Omnicam (26.9 μm), and E4D (77.5 μm). The greatest deviation was generally observed at the line angles between the preparation surfaces. The axiogingival line angle was the most error-prone location in the cavity preparations. An increased tendency to produce a more accurate impression was observed when the cavity had a greater width and more divergent walls. Conclusions The trueness of digital scans was influenced by the type of IOS and the location within a prepared cavity. The trueness decreased at the line angles between the preparation surfaces, particularly at the axiogingival line angle. Among the tested IOSs, E4D produced the least accurate digital scans.

The aim of this study was to evaluate the trueness of 5 intraoral scanners (IOSs) for digital impression of simulated implant scan bodies in a complete-arch model. A 3D printed full-arch mandible model made of Co-Cr with a total of 6 bilaterally positioned cylinders in the canine, second premolar, and second molar area served as the study model. Digital scans of the model were made with a reference scanner (steroSCAN neo) and 5 IOSs (CEREC Omnicam, CS3600, i500, iTero Element, and TRIOS 3) (n=10). For each IOS’s dataset, the XYZ coordinates of the cylinders were obtained from the reference point and the deviations from the reference scanner were calculated using a 3D reverse engineering program (Rapidform). The trueness values were analyzed by Kruskal-Wallis test and Mann-Whitney post hoc test. Direction and amount of deviation differed among cylinder position and among IOSs. Regardless of the IOS type, the cylinders positioned on the left second molar, nearest to the scanning start point, showed the smallest deviation. The deviation generally increased further away from scanning start point towards the right second molar. TRIOS 3 and i500 outperformed the other IOSs for complete-arch digital impression. The accuracy of the CEREC Omnicam, CS3600, and iTero Element were similar on the left side, but they showed more deviations on the right side of the arch when compared to the other IOSs. The accuracy of IOS is still an area that needs to be improved.

Statement of problem Trials comparing the overall performances of digital and conventional workflows in restorative dentistry are lacking. Purpose The purpose of the third part of this clinical study was to test whether the fit of zirconia 3-unit frameworks for fixed partial dentures fabricated with fully digital workflows differed from that of metal frameworks fabricated with the conventional workflow. Material and methods In each of 10 participants, 4 fixed-partial-denture frameworks were fabricated for the same abutment teeth according to a randomly generated sequence. Digital workflows were applied for the fabrication of 3 zirconia frameworks with Lava, iTero, and Cerec infiniDent systems. The conventional workflow included a polyether impression, manual waxing, the lost-wax technique, and the casting of a metal framework. The discrepancies between the frameworks and the abutment teeth were registered using the replica technique with polyvinyl siloxane. The dimensions of the marginal discrepancy (Discrepancymarginal) and the internal discrepancy in 4 different regions of interest (Discrepancyshoulder, Discrepancyaxial, Discrepancycusp, and Discrepancyocclusal) were assessed using a light microscope. Post hoc t tests with Bonferroni correction were applied to detect differences (α=.05). Results Discrepancyshoulder was 96.1 ±61.7 μm for the iTero, 106.9 ±96.0 μm for the Lava, 112.2 ±76.7 μm for the Cerec infiniDent, and 126.5 ±91.0 μm for the conventional workflow. The difference between the iTero and the conventional workflow was statistically significant (P=.029). Discrepancyocclusal was 153.5 ±66.8 μm for the iTero, 203.3 ±127.9 μm for the Lava, 179.7 ±63.1 μm for the Cerec infiniDent, and 148.8 ±66.8 μm for the conventional workflow. Discrepancyocclusal was significantly lower for the conventional workflow than for the Lava and the Cerec infindent workflows (P Conclusions In terms of framework fit in the region of the shoulder, digitally fabricated zirconia 3-unit frameworks presented similar or better fit than the conventionally fabricated metal frameworks. In the occlusal regions, the conventionally fabricated metal frameworks achieved a more favorable fit than the CAD-CAM zirconia frameworks.

Aim The aim of this study was to assess the accuracy of periapical radiography in measuring peri-implant bone levels. Materials and Methods Twenty-five subjects with 46 implants in need of surgical treatment for peri-implantitis were included in this cross-sectional study. Prior to surgery, periapical radiographs were taken, a prediction of type of defect was made and radiographic peri-implant bone levels (RxBL) were determined at the mesial and distal aspects. Intra-operatively, the peri-implant bone level (SurgBL) was assessed mesially, distally, buccally and orally and the type of defect was recorded. A paired t-test was applied to detect differences between inter-proximal RxBL and SurgBL. ANOVA was used to compare SurgBL at different circumferential positions. Results The mean inter-proximal RxBL was 4.0 ± 2.2 mm and the mean inter-proximal SurgBL was 5.3 ± 2.3 mm. The difference between RxBL and SurgBL was statistically significant (p = 0.014). There were no significant differences in SurgBL at the mesial, distal, buccal and oral aspects (p > 0.05). Conclusions The intra-operatively measured peri-implant bone levels were more apical than the radiographic bone levels. The intra-operatively assessed peri-implant bone levels (SurgBL) were similar at all the circumferential positions around the implant.

OBJECTIVES The objective of this study was to test whether or not the load-bearing capacity of occlusal veneers bonded to enamel and made of ceramic or hybrid materials does differ from those of porcelain-fused-to-metal or lithium disilicate glass ceramic crowns. MATERIAL AND METHODS In 80 human molars occlusal enamel was removed without extending into the dentin in order to mimic substance defects caused by attrition. The restorations were digitally designed at a standardized thickness of either 0.5 mm or 1.0 mm. For each thickness, 4 test groups were formed each including a different restorative material: "0.5-ZIR": 0.5 mm thick zirconia (Vita YZ HT); "1.0-ZIR": 1.0 mm thick zirconia (Vita YZ HT); "0.5-LDC": 0.5 mm thick lithium disilicate ceramic (IPS e.max Press); "1.0-LDC": 1.0 mm thick lithium disilicate ceramic (IPS e.max Press); "0.5-HYC": 0.5 mm thick PICN (Vita Enamic); "1.0-HYC": 1.0 mm thick PICN (Vita Enamic); "0.5-COC": 0.5 mm thick tooth shaded resin composite (Lava Ultimate) and "1.0-COC": 1.0 mm thick tooth shaded resin composite (Lava ultimate). Each group consists of 10 specimens. Two additional groups of 10 specimens each were used as controls and exhibited conventional crown preparations. In one group the crowns were made of lithium-disilicate ceramic ("CLD": IPS e.max CAD) and the other group consisted of porcelain-fused to metal crowns ("PFM"). All restorations were cemented onto the prepared teeth following the manufacturer's instruction of the corresponding luting cement. Subsequently, they were thermo-mechanically aged and then loaded until fracture. Load-bearing capacities (F) between the groups were compared applying the Kruskal-Wallis test (p

The objectives of this study were to compare conventional and computer-assisted implant planning and placement (CAIPP) protocols regarding surgical planning predictability, intraoperative complications, and patient-centered outcomes. Partially edentulous patients (N = 73) were randomly allocated to one of three treatment groups: control (C, n = 26), with preoperative planning based on conventional radiography and freehand implant placement; and test 1 (T1, n = 24) and test 2 (T2, n = 23), with two different CAIPP protocols. The clinicians' predictions of the bony morphology, materials needed for surgery, and surgery duration were matched with intrasurgical findings using kappa tests. Complications or deviations from the surgical or prosthetic protocol were recorded. Descriptive statistics were used to study the sample sorted out by treatment group. Differences between groups were evaluated with chi-square test for qualitative variables and with nonparametric Kruskal-Wallis test for quantitative continuous variables. For post-hoc tests, the Bonferroni corrected (P.016 = .05/3) Mann-Whitney test was used. CAIPP protocols showed better diagnostic potential than conventional protocols for the bone topography, need for simultaneous GBR procedures, membrane selection, and implant length predictions. The rate of surgical protocol deviations was similar in all groups, but their nature differed. Conventional protocols showed fewer splint-related incidences. Implant bed preparation and insertion could not be fully completed using the surgical splint in 3.8% of patients in C (1/26), 45.8% in T1 (11/24), and 47.8% in T2 (11/23). Deviation from the initial prosthetic plan was necessary in one case (T2; 4.4%). No biologic or technical complications were observed. CAIPP protocols showed a higher diagnostic potential than conventional protocols. A high incidence of intraoperative surgical protocol modifications to adjust suboptimal implant placements was reported for every group. Therefore, strict intraoperative implant position monitoring is mandatory for both treatment protocols.

OBJECTIVE To test the accuracy of measurement of interproximal peri-implant bone defects at titanium (Ti) and zirconium dioxide (ZrO ) implants by digital periapical radiography (PR) and cone beam computed tomography (CBCT). MATERIAL AND METHODS A total of 18 models, each containing one Ti and one ZrO implant, were cast in dental stone. Six models each were allocated to following defect groups: A-no peri-implant defect, B-1 mm width defect, C-1.5 mm width defect. The defect width was measured with a digital sliding caliper. Subsequently, the models were scanned by means of PR and CBCT. Three examiners assessed the defect width on PR and CBCT. Wilcoxon signed-rank test and Wilcoxon rank sum test were applied to detect differences between imaging techniques and implant types. RESULTS For PR, the deviation of the defect width measurement (mm) for groups A, B, and C amounted to 0.01 ± 0.03, -0.02 ± 0.06, and -0.00 ± 0.04 at Ti and 0.05 ± 0.02, 0.01 ± 0.03, and 0.09 ± 0.03 at ZrO implants. The corresponding values (mm) for CBCT reached 0.10 ± 0.11, 0.26 ± 0.05, and 0.24 ± 0.08 at Ti and 1.07 ± 0.06, 0.64 ± 0.37, and 0.54 ± 0.17 at ZrO implants. Except for Ti with defect A, measurements in PR were significantly more accurate in comparison to CBCT (p ≤ 0.05). Both methods generally yielded more accurate measurements for Ti than for ZrO . CONCLUSIONS The assessment of interproximal peri-implant defect width at Ti and ZrO implants was more accurate in PR in comparison to CBCT. Measurements in CBCT always led to an overestimation of the defect width, reaching clinical relevance for ZrO implants.

Objective To assess whether or not peri-implant soft tissue dimensions and hard tissue integration of loaded zirconia implants are similar to those of a titanium implant. Materials and methods In six dogs, two one-piece zirconia implants (VC, ZD), a two-piece zirconia implant (BPI) and a control one-piece titanium implant (STM) were randomly placed. CAD/CAM crowns were cemented at 6 months. Six months later, animals were killed and histomorphometric analyses were performed, including: the level of the mucosal margin, the extent of the peri-implant mucosa, the marginal bone loss and the bone-to-implant contact (BIC). Means of outcomes variables were calculated together with their corresponding 95% confidence intervals. Results In general, the mucosal margin was located coronally to the implant shoulder. The buccal peri-implant mucosa ranged between 2.64 ± 0.70 mm (VC) and 3.03 ± 1.71 mm (ZD) (for all median comparisons p > 0.05). The relative marginal bone loss ranged between 0.65 ± 0.61 mm (BPI) and 1.73 ± 1.68 mm (ZD) (buccal side), and between 0.55 ± 0.37 mm (VC) and 1.69 ± 1.56 mm (ZD) (lingual side) (p > 0.05). The mean BIC ranged between 78.6% ± 17.3% (ZD) and 87.9% ± 13.6% (STM) without statistically significant differences between the groups (p > 0.05). Conclusions One- and two-piece zirconia rendered similar peri-implant soft tissue dimensions and osseointegration compared to titanium implants that were placed at 6 months of loading. Zirconia implants, however, exhibited a relatively high fracture rate.

BACKGROUND Reference elements are necessary to transfer a virtual planning into reality for guided implant placement. New systems allow matching optical scans with three-dimensional radiographic images. PURPOSE To test whether digitally designed three-dimensional printed templates (D-temp) fabricated by matching surface scans and cone beam computed tomography (CBCT) images differ from the templates fabricated in-lab (L-temp) by using a physical transfer device for the positioning of the guiding sleeves. MATERIALS AND METHODS L-temp were fabricated for eight human lower cadaver-jaws applying a digital planning software program (smop, Swissmeda AG, Zurich, Switzerland) using a Lego® (Lego Group, KIRKBI A/S, Billund, Denmark) brick as reference element and the respective transfer device (X1-table). Additionally, digital templates (D-temp) using the identical planning data sets and software were virtually designed and three-dimensional printed, after matching a surface scan with CBCT data. The accuracy of both templates for each planning was evaluated determining the estimated coronal, apical, and angular deviation if templates were used for implant placement. RESULTS Mean coronal deviations for L-temp were 0.31 mm (mesial/distal), 0.32 mm (lingual/buccal), and 0.16 mm and 0.23 mm for D-temp, respectively. The mean apical deviations for L-temp were 0.50 mm (mesial/distal), 0.50 mm (lingual/buccal). and 0.25 mm and 0.34 mm for the D-temp, respectively. Differences between both devices were statistically significant (p

Objective To evaluate the volumetric changes occurring from prosthesis insertion to the 1-year follow-up (FU) using one- and two-piece dental implants. Methods Sixty patients were randomly assigned to receive one-piece or two-piece implants. Casts were obtained at baseline (insertion of final reconstruction) and at 1 year of loading. Finally, 33 pairs of casts (BRA = 18, STM = 15) were deemed appropriate for volumetric analysis of the peri-implant tissues. If the patients had more than one implant, one was randomly selected for analysis. Casts were scanned to obtain stereolithography (STL) files. Baseline and 1-year FU digital models were superimposed with an image analysis program. Linear and volumetric measurements were performed including (i) crown height changes (CHCs), (ii) volumetric changes, and (iii) changes in tissue thickness at three levels below the mucosal margin on the buccal side of the implants (at 1,3, and 5 mm). The Mann–Whitney U-test and the paired t-test were used to analyze the data between the two groups using the patient as the unit of analysis. Results No significant baseline differences were observed between the one- and two-piece groups for the linear measurements. The mean CHCs in the two-piece group amounted to 0.02 mm (SD ± 0.32), whereas the one-piece group exhibited a change of −0.17 mm (±0.57). The mean volume changes (VCs) were −0.12 mm (±0.27) (two-piece group) and −0.03 mm (±0.29) (one-piece group). With regard to the changes in tissue thickness, the two-piece group presented a change of −0.15 mm (±0.20) at 1 mm, −0.06 mm (±0.20) at 3 mm, and −0.2 mm (±0.51) at 5 mm. The respective values for the one-piece group were −0.03 mm (±0.35), 0.01 mm (±0.28), and −0.01 mm (±0.51) at the three levels. None of the differences in linear measurements between baseline and the 1-year FU reached significance. Positive correlations were seen for tissue thickness changes at 1 and 3 mm for both groups (P

The purpose of this study was to test whether prosthetic treatment with different intraradicular posts influences the color of the buccal gingiva at teeth restored with zirconia crowns. A total of 31 patients in need of a full-coverage single crown at an endodontically treated premolar, canine, or incisor in the maxilla or the mandible were included. The patients were randomly assigned to receive composite build-ups using titanium (Ti), zirconia (Zi), or glass-fiber (Gf) posts or a build-up using no post at all (NP). All the teeth were restored with veneered zirconia single crowns. Spectrophotometric color measurements of the buccal gingiva were taken at the test teeth prior to and after the prosthetic treatment, and at the contralateral vital control tooth. The differences of the color components ΔL, Δa, and Δb and the total color difference ΔE between the test tooth prior to and after treatment and between the test and control tooth were calculated. The color differences were analyzed to determine whether they varied from 0 and 3.7, the threshold for detection by the human eye. Analysis of variance was performed to compare ΔE, ΔL, Δa, and Δb in the four post groups. The prosthetic treatment induced a significant color change ΔE in all the groups (Ti: ΔE1 = 6.4 ± 1.9; Zi: 7.1 ± 2.0; Gf: 6.2 ± 3.5; NP: 6.6 ± 3.5). There was no significant difference between Ti, Zi, Gf, and NP with respect to ΔE, ΔL, Δa, and Δb. Gingival color ΔE differed significantly between the test and control teeth before (Ti: ΔE = 6.8 ± 3.0; Zi: 9.0 ± 3.5; Gf: 5.7 ± 2.1; NP: 8.2 ± 2.8) and after prosthetic treatment (Ti: ΔE = 6.0 ± 2.8; Zi: 7.1 ± 2.9; Gf: 7.2 ± 3.0; NP: 6.9 ± 2.6). The use of different intraradicular posts (titanium, zirconia, glass fiber) or no post at all did not influence the color of the buccal gingiva at teeth restored with zirconia crowns. There was a significant gingival color difference between endodontically treated teeth and vital control teeth, both before and after prosthetic treatment.

Objective The aim of this pilot study was to test whether a porcine collagenated bone substitute block (PCBB) and collagen membrane (CM) loaded with bone morphogenetic protein-2 (BMP-2) used for horizontal ridge augmentation differ from PCBB and CM without BMP-2 regarding the osseointegration of the grafting material and the maintenance of the ridge contour. Material and methods Two semi-saddle bone defects were created in each side of the mandible of six dogs. The defects were randomly allocated to receive one of the following treatments: bone augmentation using (1) PCBB, (2) PCBB loaded with BMP-2 (PCBB-BMP2), (3) PCBB + CM and (4) PCBB + CM loaded with BMP-2 (PCBB + CM-BMP2). After 12 weeks, one titanium implant was inserted into every site. After 8 weeks, one central histological section of each site was prepared. Histomorphometrical assessments were performed evaluating the augmented area (AA), the area of new bone (NB) (primary outcome), residual bone substitute (BS) and non-mineralized tissue (NMT) within AA in mm2. In addition, the most coronal and the most buccal localizations of new bone and residual bone substitute, and the most coronal bone-to-implant contact were measured in mm. Results Clinically, all PCBB were firmly integrated and permitted implant placement. All the implants osseointegrated and exhibited complete hard-tissue coverage of the buccal surface. Bone ingrowth always reached the central portions of PCBB. AA measured 10.4 ± 4.2 mm2 for PCBB, 11.8 ± 2.8 mm2 for PCBB-BMP2, 9.8 ± 2.9 mm2 for PCBB + CM and 8.5 ± 2.2 mm2 for PCBB + CM-BMP2. Only the difference between PCBB-BMP2 and PCBB + CM-BMP2 was statistically significant (P = 0.031). NB reached 2.3 ± 1.3 mm2 for PCBB, 2 ± 0.5 mm2 for PCBB-BMP2, 2.7 ± 1.2 mm2 for PCBB + CM and 1.8 ± 0.7 mm2 for PCBB + CM-BMP2. There were no statistically significant differences regarding NB, the most coronal and the most buccal localizations of new bone, residual bone substitute and bone-to-implant contact (P > 0.05). Conclusions The addition of BMP-2 to PCBB or CM used for horizontal ridge augmentation did not render a statistically significant improvement in the maintenance of the augmented ridge contour and the new bone formation. PCBB with and without CM showed pronounced bone ingrowth and capacity to maintain the augmented ridge contour. In all the regions previously augmented with PCBB, the implants successfully integrated and presented with complete hard-tissue coverage.

AIM: To spectrophotometrically and visually test whether the peri-implant mucosal color differs from the color of the natural gingiva. MATERIAL AND METHODS: Forty single implants in the incisor and premolar region of 40 patients were assessed 3-7 years after implant placement. The differences of the color components lightness, chroma along red-green axis, chroma along yellow-blue axis, and the total color difference ΔE between peri-implant mucosa and natural gingiva were measured with a spectrophotometer. The color difference between peri-implant mucosa and natural gingiva was visually evaluated by clinicians and rated as "clinically visible" or "clinically invisible" from speaking distance. The dimensions of peri-implant mucosa and gingiva at the mid-buccal aspect were evaluated by using cone-beam CT. Spearman analysis was performed to detect correlations between different variables. Two-sided t-test, ANOVA, Mann-Whitney, and Kruskal-Wallis tests were applied to detect differences between the groups. RESULTS: The spectrophotometrically assessed color difference ΔE between peri-implant mucosa and natural gingiva amounted to 7.0 ± 3.9. The peri-implant mucosa presented a significant dark, greenish and bluish discoloration in comparison with gingiva at control teeth. Clinical investigation revealed that in 60% of sites the color difference between peri-implant mucosa and natural gingiva was clinically visible from speaking distance. The threshold value ΔE for the extraoral clinical distinction of mucosal color differences measured 7.5. When comparing the groups with visible and invisible color differences with respect to the three color components, a significant difference was found only for chroma along yellow-blue axis. In the group with visible color difference, mucosa presented a bluish discoloration. Correlation analysis indicated that with an increase in mucosal thickness, a trend for smaller ΔE was found. CONCLUSION: The spectrophotometrically assessed color of the peri-implant mucosa revealed more dark, green and blue components compared to the natural gingiva. At 60% of the implants, peri-implant mucosal discoloration was visible from speaking distance. The sites with visible and those with invisible mucosal discolorations differed significantly only regarding the chroma along yellow-blue axis.

Objectives To test whether GBR with an L-shaped soft-block bone substitute and particulate bone substitute differs from GBR with particulate bone substitute as regards the volume stability of the augmented region during flap closure. Materials and methods Twenty peri-implant box-shaped bone defects were created in 10 pig mandibles. Every bone defect was augmented with each of the following two GBR procedures in turn: control group – particulate xenograft applied buccally + collagen membrane + pins; test group – particulate xenograft applied buccally + L-shaped soft-block xenograft applied buccally and occlusally + collagen membrane + pins. Cone-beam computed tomography scans were obtained before and after wound closure. The horizontal thickness (HT) of the augmented region (bone substitute + membrane) was assessed at the implant shoulder (HT0 mm) and at 1 mm to 5 mm apical to the implant shoulder (HT1 mm-HT5 mm). In the test group, the vertical thickness (VT) and 45° thickness (45-T) of the augmented region were measured from the implant shoulder. The changes in HT during flap suturing were calculated as absolute (mm) and relative values (%). Repeated-measures ANOVAs were used for statistical analysis. Results The reduction in HT0 mm was 20.5 ± 23.3% (SD) in the control group and 2.4 ± 9.2% (SD) in the test group (P = 0.014). There were no statistically significant differences in changes in HT1–5 mm between the groups (P > 0.05). In the test group, the reduction in VT amounted to 28.0 ± 11.9% (SD) and the reduction in 45-T amounted to 24.8 ± 10.2% (SD) (P

Aim To test whether an equine bone substitute block used for guided bone regeneration (GBR) of peri-implant defects differs from bovine block or particulate bone substitutes regarding the hard and soft tissue contours of the augmented ridge. Material & Methods Two semi-saddle bone defects were prepared in each side of the mandible of eight dogs, and one titanium implant was inserted into every defect. The defects were randomly allocated to receive one of the following treatments: bone augmentation by GBR using (1) particulate deproteinized bovine bone mineral (DBBM) + a collagen membrane (CM), (2) block DBBM + CM, (3) equine bone substitute block + CM, and (4) empty controls. After 4 months, the jaws were scanned by means of cone beam computed tomography (CBCT). CBCT analysis was performed in one central and two lateral (mesial and distal) regions of interest (ROI) of each site evaluating the horizontal thickness of the augmented hard tissue (HThard tisue) and the total thickness of hard and soft tissue (HTtotal). The Wilcoxon-Pratt signed rank test was used for statistical analysis. Results In the majority of ROIs, equine and bovine blocks rendered significantly higher values in HThard tissue and HTtotal than controls (P 0.05). In the central ROI, HThard tissue at the level of the implant shoulder measured 1.7 ± 1.4 mm for equine blocks, 1.7 ± 1.0 mm for DBBM blocks, 0.9 ± 1.2 mm for particulate DBBM, and 0 ± 0 mm for controls. The corresponding values in the lateral ROI reached 1.9 ± 1.1 mm for equine blocks, 1.2 ± 0.8 mm for DBBM blocks, 1.0 ± 0.9 mm for particulate DBBM, and 0 ± 0 mm for controls. Conclusions GBR with bone substitute blocks lead to higher ridge dimensions than empty controls. The equine block with CM rendered the most favorable outcomes in hard and soft tissue contours followed by DBBM block and DBBM granulate with CM.

AIM: The aim of this study was to test whether or not the intensity of artifacts around implants in cone-beam computed tomography (CBCT) differs between titanium, titanium-zirconium and zirconium dioxide implants. MATERIALS AND METHODS: Twenty models of a human mandible, each containing one implant in the single-tooth gap position 45, were cast in dental stone. Five test models were produced for each of the following implant types: titanium 4.1 mm diameter (Ti4.1 ), titanium 3.3 mm diameter (Ti3.3 ), titanium-zirconium 3.3 mm diameter (TiZr3.3 ) and zirconium dioxide 3.5-4.5 mm diameter (ZrO3.5-4.5 ) implants. For control purposes, three models without implants were produced. Each model was scanned using a CBCT device. Gray values (GV) were recorded at eight circumferential positions around the implants at 0.5 mm, 1 mm and 2 mm from the implant surface (GVT est ). GV were assessed in the corresponding volumes of interest (VOI) in the control models without implants (GVC ontrol ). Differences of gray values (ΔGV) between GVT est and GVC ontrol were calculated as percentages. One-way ANOVA and post hoc tests were applied to detect differences between implant types. RESULTS: Mean ΔGV for ZrO3.5-4.5 presented the highest absolute values, generally followed by TiZr3.3 , Ti4.1 and Ti3.3 implants. The differences of ΔGV between ZrO3.5-4.5 and the remaining groups were statistically significant in the majority of the VOI (P ≤ 0.0167). ΔGV for TiZr3.3 , Ti4.1 and Ti3.3 implants did not differ significantly in the most VOI. For all implant types, ΔGV showed positive values buccally, mesio-buccally, lingually and disto-lingually, whereas negative values were detected mesially and distally. CONCLUSIONS: Zirconium dioxide implants generate significantly more artifacts as compared to titanium and titanium-zirconium implants. The intensity of artifacts around zirconium dioxide implants exhibited in average the threefold in comparison with titanium implants.

Aim To test whether titanium-zirconium (TiZr) 3.3 mm diameter implants perform differently from titanium (Ti) 4.1 mm diameter implants with respect to marginal bone level (MBL) and clinical parameters. Material and methods Forty subjects in need of a single implant-supported crown in the anterior or premolar regions were recruited in two centres. After random allocation, either a Ti or a TiZr implant was placed. Definitive crowns were inserted 6 months after implant placement. Implant survival, change in MBL, clinical parameters and occurrence of adverse events were assessed at the 1-year examination. Results At 1 year, 38 of the 40 included patients were examined (18 Ti and 20 TiZr implants). All the implants were in place and stable. From the implant placement to the 1-year examination, the change of MBL amounted to -0.40 mm in the Ti group and -0.41 mm in the TiZr group. There were no significant differences between the groups regarding the change in MBL, the clinical parameters and the occurrence of adverse events. Conclusions The use of TiZr implants with narrow diameter for the support of single crowns in the anterior and premolar regions leads to successful tissue integration and clinical performance over a 1-year period.

BACKGROUND: The treatment of mandibular edentulism with implant fixed complete dental prostheses (IFCDPs) is a routinely used treatment option. PURPOSE: The study aims to report the implant and prosthodontic survival rates associated with IFCDPs for the edentulous mandible after an observation period of a minimum 5 years. MATERIALS AND METHODS: An electronic MEDLINE/PubMED search was conducted to identify randomized controlled clinical trials and prospective studies with IFCDPs for the edentulous mandible. Clinical studies with at least 5-year follow-up were selected. Pooled data were statistically analyzed and cumulative implant- and prosthesis survival rates were calculated by meta-analysis, regression, and chi-square statistics. Implant-related and prosthesis-related factors were identified and their impact on survival rates was assessed. RESULTS: Seventeen prospective studies, including 501 patients and 2,827 implants, were selected for meta-analysis. The majority of the implants (88.5% of all placed implants) had been placed in the interforaminal area. Cumulative implant survival rates for rough surface ranged from 98.42% (95% confidence interval [CI]: 97.98-98.86) (5 years) to 96.86% (95% CI: 96.00-97.73) (10 years); smooth surface implant survival rates ranged from 98.93% (95% CI: 98.38-99.49) (5 years) to 97.88% (95% CI: 96.78-98.98) (10 years). The prosthodontic survival rates for 1-piece IFCDPs ranged from 98.61% (95% CI: 97.80-99.43) (5 years) to 97.25% (95% CI: 95.66-98.86) (10 years). CONCLUSION: Treatment with mandibular IFCDPs yields high implant and prosthodontic survival rates (more than 96% after 10 years). Rough surface implants exhibited cumulative survival rates similar to the smooth surface ones (p > .05) in the edentulous mandible. The number of supporting implants and the antero-posterior implant distribution had no influence (p > .05) on the implant survival rate. The prosthetic design and veneering material, the retention type, and the loading protocol (delayed, early, and immediate) had no influence (p > .05) on the prosthodontic survival rates.

Digital approaches to assess the misfit of fixed dental prostheses have been limited to in vitro evaluation. The present article describes a fully digital technique for the in vivo assessment of the fit of fixed dental prostheses by means of a chairside optical scanner and software for 3-dimensional (3D) analysis. The 3D digital capture is performed in 3 steps: an extraoral scan of the restoration, an intraoral scan of the abutment tooth, and an intraoral registration scan of the restoration positioned on the abutment tooth.

Aim The aim of this study was to test whether or not soft tissue augmentation with a collagen matrix (VCMX) leads to a similar increase in ridge width around dental implants compared to the use of an autogenous subepithelial connective tissue graft (SCTG). Materials and Methods In 12 dogs, immediate dental implants were placed with simultaneous guided bone regeneration. Three months later, soft tissue volume augmentation was performed by randomly allocating three treatment modalities to these sites [VCMX, SCTG, sham-operated group (control)]. Dogs were sacrificed at 1 (n = 4), 2 (n = 4) or 6 months (n = 4). Descriptive histology and histomorphometric measurements for soft tissue thickness were performed on non-decalcified sections. Results The horizontal soft tissue thickness was maximal at the most coronal level (alveolar crest) at 1 month (VCMX: 2.1 ± 1.6 mm; SCTG: 2.5 ± 1.7 mm; p = 0.877) and decreased until 6 months. At 6 months, the greatest mucosal thickness was at a level 3.5 mm below the crest (VCMX: 0.8 ± 0.3 mm; SCTG: 0.7 ± 0.2 mm) (p = 0.754). Control sites revealed no relevant soft tissue augmentation at any level and any time-point. Tissue integration for VCMX and SCTG were favourable with minimal inflammatory reactions. Conclusions Soft tissue volume augmentation at implant sites was obtained to a similar extent using VCMX and SCTG up to 2 months. Thereafter, degradation and remodelling processes were enhanced leading to a minimal increase in soft tissue thickness at 6 months for VCMX and SCTG.

Clinical studies are needed to evaluate the entire digital and conventional workflows in prosthetic dentistry.The purpose of the second part of this clinical study was to compare the laboratory production time for tooth-supported single crowns made with 4 different digital workflows and 1 conventional workflow and to compare these crowns clinically.For each of 10 participants, a monolithic crown was fabricated in lithium disilicate-reinforced glass ceramic (IPS e.max CAD). The computer-aided design and computer-aided manufacturing (CAD-CAM) systems were Lava C.O.S. CAD software and centralized CAM (group L), Cares CAD software and centralized CAM (group iT), Cerec Connect CAD software and lab side CAM (group CiL), and Cerec Connect CAD software with centralized CAM (group CiD). The conventional fabrication (group K) included a wax pattern of the crown and heat pressing according to the lost-wax technique (IPS e.max Press). The time for the fabrication of the casts and the crowns was recorded. Subsequently, the crowns were clinically evaluated and the corresponding treatment times were recorded. The Paired Wilcoxon test with the Bonferroni correction was applied to detect differences among treatment groups (α=.05).The total mean (±standard deviation) active working time for the dental technician was 88 ±6 minutes in group L, 74 ±12 minutes in group iT, 74 ±5 minutes in group CiL, 92 ±8 minutes in group CiD, and 148 ±11 minutes in group K. The dental technician spent significantly more working time for the conventional workflow than for the digital workflows (P.001). No statistically significant differences were found between group L and group CiD or between group iT and group CiL. No statistical differences in time for the clinical evaluation were found among groups, indicating similar outcomes (P.05).Irrespective of the CAD-CAM system, the overall laboratory working time for a digital workflow was significantly shorter than for the conventional workflow, since the dental technician needed less active working time.

Aim To test whether an equine bone substitute block used for guided bone regeneration (GBR) of peri-implant defects renders different results from bovine block or particulated bone substitutes regarding the dimensions of the augmented ridge and the amount of new bone. Material and methods Mandibular premolars and molars were extracted in eight dogs. After 4 months, four semi-saddle bone defects were created in each mandible and one titanium implant was inserted into every site. Bone augmentation by GBR was attempted using the following randomly assigned modalities: (i) particulated deproteinized bovine bone mineral (DBBM) + a collagen membrane (CM), (ii) block DBBM + CM, (iii) equine bone substitute block + CM, and (iv) empty controls. After 4 months, one central and two lateral sections of each site were prepared. Descriptive histological and histomorphometrical assessments were performed evaluating the augmented area (AA) within the former bone defect, the area of mineralized tissue (MT), non-mineralized tissue (NMT), and residual bone substitute (BS) within AA, the horizontal thicknesses of the augmented region (HTaugm ) and of the mucosa (HTmucosa ). Results At the central sections, AA measured 11.2 ± 3.3 mm(2) for the equine block, 9.5 ± 2.6 mm(2) for DBBM block, 7.9 ± 4.8 mm(2) for particulated DBBM, and 2.4 ± 2.1 mm(2) for the empty control. All GBR groups rendered significantly higher values of AA in comparison with control (P ≤ 0.05). The differences in AA between GBR groups did not reach statistical significance (P > 0.05). The equine block rendered the highest values in HTaugm , although only the differences between equine block and control as well as equine block and DBBM block were statistically significant (P ≤ 0.05). With respect to HTmucosa , all GBR groups reached significantly higher values compared to control (P ≤ 0.05). The equine block revealed the most pronounced signs of graft degradation. Conclusions Guided bone regeneration lead to higher ridge dimensions and thicker covering mucosa than empty controls. The equine block with CM resulted in the most favorable outcomes regarding the maintenance of ridge contour. There were no significant differences regarding amount of new bone between GBR treatments.

OBJECTIVES The aim was to test whether or not the marginal bone-level alterations of loaded zirconia implants are similar to the bone-level alterations of a grade 4 titanium one-piece dental implant. MATERIALS AND METHODS In six dogs, all premolars and the first molars were extracted in the mandible. Four months later, three zirconia implants (BPI, VC, ZD) and a control titanium one-piece (STM) implant were randomly placed in each hemimandible and left for transmucosal healing (baseline). Six months later, CAD/CAM crowns were cemented. Sacrifice was scheduled at 6-month postloading. Digital X-rays were taken at implant placement, crowns insertion, and sacrifice. Marginal bone-level alterations were calculated, and intra- and intergroup comparisons performed adjusted by confounding factors. RESULTS Implants were successfully placed. Until crown insertion, two implants were fractured (one VC, one ZD). At sacrifice, 5 more implants were (partly) fractured (one BPI, four ZD), and one lost osseointegration (VC). No decementation of crowns occurred. All implant systems demonstrated a statistically significant (except VC) loss of marginal bone between baseline and crown insertion ranging from 0.29 mm (VC; P = 0.116) to 0.80 mm (ZD; P = 0.013). The estimated marginal bone loss between baseline and 6 months of loading ranged between 0.19 mm (BPI) and 1.11 mm (VC), being statistically significant for STM and VC only (P < 0.05). The changes in marginal bone levels were statistically significantly different between zirconia implants and control implants (STM vs. BPI P = 0.007; vs. VC P = 0.001; vs. ZD P = 0.011). CONCLUSIONS Zirconia implants were more prone to fracture prior to and after loading with implant-supported crowns compared to titanium implants. Individual differences and variability in the extent of the bone-level changes during the 12-month study period were found between the different implant types and materials.

Objective The objective of this study was to evaluate the dimensions of buccal bone and soft tissue at immediately placed implants over a 7-year period. Material and methods Twenty-four patients, that participated in a clinical prospective study and received implants immediately placed into extraction socket, were enrolled for this study. Residual bone defects were grafted with xenogenic bone substitute and covered by means of collagen membrane. Baseline examination included measurements of full-mouth plaque and bleeding scores, width of keratinized mucosa, and dimensions of residual bone defects at the buccal aspect. Seven years after implant placement, full-mouth plaque score, full-mouth bleeding score, width of keratinized mucosa, and probing pocket depth were assessed and cone beam computed tomography images acquired. Dimensions of buccal bone and soft tissue were evaluated on the cross-sectional cone beam computed tomography reconstructions. Differences between two time-points were tested using the two-sided t-test. Correlation analysis was used to investigate the influence of baseline bone defect dimensions on the bone dimensions measured at the 7-year follow-up. Results and conclusions Fourteen patients attended the follow-up examination. In five implants almost no buccal bone was detected, whereas in the remaining nine implants the buccal bone was found covering the rough implant surface. No correlation was found between initial bone defects and bone dimensions at the follow-up examination. The sites without radiographically detectable buccal bone at the 7-year control presented with 1 mm more apical mucosal level in comparison to implants with intact buccal bone.

Background: The accuracy of implant casts generated with various impression techniques was mainly investigated in vitro resulting in limited clinical data. Purpose: (1) To compare the three-dimensional (3-D) accuracy of splinted and non-splinted impression techniques to the control casts (verification jigs) that had been used for actual patient treatment; and (2) to determine the maximum level of clinically undetectable misfit. The null hypothesis was that there would be no significant difference in the accuracy of casts generated with different impression techniques. Materials and methods: The implant casts used for the prosthetic rehabilitation of 12 edentulous jaws with CAD/CAM zirconia, implant-fixed complete dental prosthesis (IFCDP) were included in this study. Intraoral acrylic jigs were used to fabricate index casts. Splinted and non-splinted, open-tray techniques were used to generate two casts. Optical scanning acquisition of the x-coordinates, y-coordinates and z-coordinates of the implant positions for each individual cast was performed. The “best fit” algorithm was used with computer software to superimpose the scanning datasets. Group I (n=12) included casts from the splinted impression technique vs. acrylic jig casts, and group II (n=12) included casts from non-splinted technique vs. jig casts. Results: The paired t-test and Wilcoxon's signed ranks test were used to compare the 3-D discrepancies within and between groups I (splinted vs. jig) and II (non-splinted vs. jig), respectively. Significant difference was found at the x-axis, y-axis and 3-D between groups I and II (P 0.05). Within subject, global 3-D discrepancies between groups I and II were significantly different (P

Introduction: The treatment of dentinogenesis imperfecta is complex and requires a team approach. The aim of this case report is to describe the steps taken in the long-term rehabilitation of a middle-aged female with dentinogenesis imperfecta with severe attrition. This treatment included an initial temporary treatment to restore esthetic appearance and function followed by a complete prosthetic rehabilitation with implants in the second stage.In advanced stages of dentinogenesis imperfecta, patients can benefit from full-mouth rehabilitation where the deteriorated – yet still present – teeth can be used as abutments for a fixed, temporary restoration throughout the stages of treatment. Detailed pretreatment planning of how much bone and soft tissue are to be removed and an accurate determination of where the implants should be placed must be considered very thoroughly.Case Presentation: All teeth were ultimately extracted and replaced with fixed implant-supported prostheses in a staged approach using re...

Aim: The aim of the present review was to systematically assess the dental literature in terms of soft tissue grafting techniques. The focused question was: is there superiority of one method over others for augmentation and stability of the augmented soft tissue in terms of increasing the width of keratinized tissue (part 1), and gain in soft tissue volume (part 2). Methods: A Medline search was performed for human studies focusing on augmentation of keratinized tissue and/or soft tissue volume, and complimented by additional hand searching. Relevant studies were identified and statistical results reported for meta-analyses including the test minus control weighted mean differences (WMD) with 95% confidence intervals (CI), the I-squared statistic for tests of heterogeneity, and the number of significant studies. Results: Twenty-five (part 1) and three (part 2) studies met the inclusion criteria; 14 studies (part 1) were eligible for comparison using meta-analyses. An apically positioned flap/vestibuloplasty (APF/V) procedure resulted in a statistically significantly greater gain in keratinized tissue than untreated controls. APF/V plus autogenous tissue revealed statistically significant more attached gingiva compared to untreated controls and a borderline statistical significance compared to APF/V plus allogenic tissue. Statistically significantly more shrinkage was observed for APF/V plus allogenic graft compared to APF/V plus autogenous tissue. Patient-centered outcomes did not reveal a superiority of any of the treatment methods regarding post-operative complications. The 3 studies reporting on soft tissue volume augmentation could not be compared due to lack of homogeneity. The use of subepithelial connective tissue grafts (SCTGs) resulted in statistically significantly more soft tissue volume gain compared to free gingival grafts (FGGs). Conclusions: APF/V is a successful treatment concept to increase the width of keratinized tissue or attached gingiva around teeth. The addition of autogenous tissue statistically significantly increases the width of attached gingiva. For soft tissue volume augmentation only limited data are available favoring SCTGs over FGG.

PURPOSE: The aim of this study was to test whether or not implants associated with bone regeneration show the same survival and success rates as implants placed in native bone in patients requiring both forms of therapy. MATERIAL AND METHODS: Thirty-four patients (median age of 60.3 years, range 18-77.7 years) had been treated 5 years before the follow-up examination. Machined screw-type implants were inserted following one of two surgical procedures: (1) simultaneously with a guided bone regeneration (GBR) procedure, which involved grafting with xenogenic bone substitute material, autogenous bone or a mixture of the two and defect covering with a bio-absorbable collagen membrane (test) and (2) standard implantation procedure without bone regeneration (control). For data recording, one test and one control implant from each patient were assessed. Examination included measurements of plaque control record (PCR), probing pocket depth (PPD), bleeding on probing (BOP), width of keratinized mucosa (KM), frequency of situations with supra-mucosal location of the crown margin, implant survival assessment and radiographic examination. Radiographs were digitized to assess the marginal bone level (MBL). Differences between groups were tested using the one-sample t-test. The estimation of survival rate was based on Kaplan-Meier analysis. RESULTS: The follow-up period of the 34 GBR and 34 control implants ranged from 49 to 70 months (median time 57 months). Cumulative survival rates reached 100% for the GBR group and 94.1% for the control group without statistical significance. No statistically significant differences for clinical and radiographic parameters were found between the two groups regarding PCR, BOP, PPD, KM and MBL. CONCLUSION: The present study showed that, clinically, implants placed with concomitant bone regeneration did not performed differently from implants placed into native bone with respect to implant survival, marginal bone height and peri-implant soft tissue parameters.

AIM To test whether titanium-zirconium (Ti-Zr) 3.3 mm diameter implants perform differently from titanium (Ti) 4.1 mm diameter implants with respect to marginal bone level (MBL) and clinical parameters. MATERIAL AND METHODS Forty patients in need of a single-implant crown in the anterior or premolar regions were enrolled in two centres. Following random allocation, either a Ti-Zr or a Ti implant was inserted. Porcelain-fused-to-metal crowns were inserted 6 months after implantation. Implant survival, change in MBL, clinical parameters, change in mid-facial mucosa and papilla levels, and the occurrence of biological and technical complications were assessed at the 3-year follow-up. RESULTS At 3 years, 32 of the 40 included patients were examined (15 Ti, 17 Ti-Zr). There were no implant failures. From the implant placement to 3 years, the median change in mean MBL amounted to 0.21 mm (mean: -0.31) in the Ti group and 0.10 mm (mean: -0.40) in the Ti-Zr group. There were no significant differences between the groups with respect to the change in MBL, the change in mucosa levels, and the occurrence of complications. CONCLUSIONS Ti-Zr implants with 3.3 mm diameter used for the support of single crowns in the anterior and the premolar regions did not differ from Ti implants with 4.1 mm diameter regarding the clinical performance over a 3-year period. This article is protected by copyright. All rights reserved.

In 2011, the first consensus conference on guidelines for the use of cone-beam computed tomography (CBCT) was convened by the Swiss Society of Dentomaxillofacial Radiology (SGDMFR). This conference covered topics of oral and maxillofacial surgery, temporomandibular joint dysfunctions and disorders, and orthodontics. In 2014, a second consensus conference was convened on guidelines for the use of CBCT in endodontics, periodontology, reconstructive dentistry and pediatric dentistry. The guidelines are intended for all dentists in order to facilitate the decision as to when the use of CBCT is justified. As a rule, the use of CBCT is considered restrictive, since radiation protection reasons do not allow its routine use. CBCT should therefore be reserved for complex cases where its application can be expected to provide further information that is relevant to the choice of therapy. In periodontology, sufficient information is usually available from clinical examination and periapical radiographs; in endodontics alternative methods can often be used instead of CBCT; and for implant patients undergoing reconstructive dentistry, CT is of interest for the workflow from implant planning to the superstructure. For pediatric dentistry no application of CBCT is seen for caries diagnosis.