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Purpose: To analyze the impact of microthreads on the stresses generated in peri-implant bone surrounding reduced-diameter zirconia and titanium implants under loading., Materials and Methods: Two custom-made zirconia implants, microthreaded or smooth neck, and two titanium replicas were made. Strains were recorded in the peri-implant region under 200-N vertical load. Two three-dimensional finite element models were created. Zirconia and titanium implants were tested under 200-N vertical load and 150-N oblique load at 30, 45, and 60 degrees., Results: The lowest peri-implant strain (40 ± 6 με) under vertical load was related to the microthreaded zirconia implant. Oblique load showed higher von Mises stress on bone in comparison with vertical load. The von Mises stress increased by increasing the load angle by approximately 2 MPa per degree. Under oblique load, implants showed more stress in peri-implant bone and the implant itself. On the other hand, total strains were within physiologic limits in all tested cases., Conclusion: Stresses within the peri-implant cortical bone around the reduced-diameter implant with microthreads appeared to be superior compared with the smooth-neck one. Reduced-diameter zirconia implants induced less stress on bone in comparison with the titanium implants, suggesting that zirconia is a feasible alternative for titanium.

Purpose: To evaluate the long-term clinical performance of prosthetic reconstructions on one-piece implants, with a focus on technical and biological complications., Materials and Methods: An electronic MEDLINE search complemented by a manual search was conducted to identify randomized and prospective controlled clinical trials on one-piece implants. Additional inclusion criteria were a mean follow-up period of at least 5 years and an inception cohort where more than 80% of the enrolled patients remained in the study at the 5- or 10-year observation point., Results: Sixty-six studies from an initial yield of 597 titles were selected, and the data were extracted. Of the full-text articles examined, 46 were excluded and a total of 20 articles were finally selected. All studies were published between 1995 and 2011. Two different study designs were identified: 4 randomized controlled trials and 16 prospective cohort studies. The studies were analyzed and classified according to study type, patient characteristics, prosthetic characteristics, and biologic and technical complications after 5 and 10 years. The meta-analysis of the included studies showed a prosthetic survival rate for one-piece, one-part implants of 82.81% after 5 years and 97.85% and 98.24% in two-part implants after 5 and 10 years, respectively. Although the prosthetic survival rates were high, complications were frequent: complications of the suprastructure (18.44% to 18.75%), screw loosening/fracture (7.64%), soft-tissue complications (4.69% to 8.25%), sensory disturbances (0.36% to 6.25%), implant loss before loading (0% to 0.23%) and during function (1.10% to 3.21%), and implant fracture (0.0004%)., Conclusion: Within the limits of this systematic review, it can be concluded that despite high long-term prosthetic survival rates, technical and biologic complications are frequent in one-piece implants, both in one-part and two-part designs. Further randomized clinical trials are needed to provide more information about the outcome of different variables associated with this type of implant design.

Purpose: The aim of this systematic review was to evaluate the long-term clinical performance of one-piece implants., Materials and Methods: An electronic MEDLINE search complemented by a manual search was conducted to identify randomized and prospective cohort studies on one-piece implants. Additional inclusion criteria were: a mean follow-up period of at least 5 years and an inception cohort where more than 80% of the enrolled patients remained in the study at the 5- or 10-year observation point., Results: Sixty-six studies from an initial yield of 597 titles were selected, and the data were extracted. Of the full-text articles examined, 46 were excluded from the final analysis. A total of 20 articles were finally selected. All studies were published between 1995 and 2011. Two different study designs were included: 4 randomized controlled trials and 16 prospective cohort studies. The studies were analyzed and classified according to the follow-up period, the type of implant surface, the type of edentulism, the type of loading protocol, and the type of setting. The meta-analysis of the included studies showed an implant survival rate for one-piece, one-part implants of 96.79% (95% CI: 94.04% to 98.71%) after 5 years. In one-piece, two-part implants, the survival rate was slightly higher: 98.16% (95% CI: 96.48% to 99.31%) after 5 years and 96.83% (95% CI: 93.12% to 99.24%) after 10 years., Conclusion: Within the limits of this systematic review, it can be concluded that high long-term survival rates can be observed with one-piece implants. Further randomized clinical trials are needed to provide more information about the outcome of different variables associated with one-piece implants.

Purpose: Immediate loading and/or restoration of dental implants requires the assessment of implant stability, which is best performed by resonance frequency analysis (RFA) prior to loading. One-piece dental implants are usually used for immediate loading, but there is currently no available reliable method to assess the primary stability of one-piece dental implants. Therefore, this study sought to validate a novel device designed for RFA measurements of one-piece implants., Material and Methods: Thirty (3.75 x 13 mm) internal-hex implants (Seven, MIS) were divided into two groups; 15 were placed in an acrylic glass block and 15 were placed in fresh porcine jawbone using 30 N/cm2 of insertion torque. Implant stability quotient (ISQ) values were measured using the Osstell Mentor device; then, a new external fixation device was attached to the implant abutment with a 10-mm arm extending from the implant to an internal-hex ring at its proximal end. ISQ values were measured at the implant's internal hex and at the internal hex of the device, and the damping ratio was calculated. The measurements were repeated with 15 (3 x 13 mm) one-piece implants (UNO, MIS) attached to the same device., Results: The damping ratio between the implant and the proximal device was 23.6% ± 4% in acrylic glass (50.1 ± 1.7 ISQ and 38.2 ± 1.8 ISQ, respectively) and 23.1% ± 3% in porcine bone (74.9 ± 2.8 ISQ and 57.5 ± 0.5 ISQ, respectively). ISQ values determined by the device on one-piece and two-piece implants were similar (57.4 ± 0.9 and 57.5 ± 0.5, respectively)., Conclusion: With the present validation of this external fixation device for the measurements of implant stability using RFA, it is now possible to measure primary stability of any one-piece implant system, obviating the need for custom-made Osstell adaptors.

Purpose: To evaluate differences in the temperature rise at the cervical area of one-piece vs two-piece implants during the setting of relined provisional crowns. Materials and Methods: A K-type thermocouple was fixed to the coronal thread of 15 one-piece implants and 15 two-piece implants that were mounted on a plexiglass apparatus. Baseline temperature (Bl Temp) was recorded before starting the curing process. The maximum temperature (Max Temp) reached during the process in both implant groups was also recorded. Total heat flux (THF) was calculated as well as the thermal amplitude (Temp-Amp) at the implant surface. Finally, the differences between the implant types were compared using unpaired t test. Results: The increase in temperature from baseline was statistically significantly greater in the one-piece implants than in the two-piece implants ( P < .01). Similarly, the THF and Temp-Amp were significantly greater in the one-piece implants compared to two-piece implants ( P < .01). Conclusions: The polymerization of PMMA-based resin temporary crowns produces a significant temperature rise in both one-piece and two-piece implants. It is advisable to use two-piece implants to restore immediately loaded implants to reduce the risk to implant surroundings that may occur due to the temperature rise at the implant neck.

Purpose: To evaluate the performance of one- and two-piece ceramic implants regarding implant survival and success and patient satisfaction. Materials and Methods: This review followed the PRISMA 2020 guidelines using PICO format and analyzed clinical studies of partially or completely edentulous patients. The electronic search was conducted in PubMed/MEDLINE using Medical Subject Headings (MeSH) keywords related to dental zirconia ceramic implants, and 1,029 records were received for detailed screening. The data obtained from the literature were analyzed by single-arm, weighted meta-analyses using a random-effects model. Forest plots were used to synthesize pooled means and 95% CI for the change in marginal bone level (MBL) for short-term (1 year), mid-term (2 to 5 years), and long-term (over 5 years) follow-up time intervals. Results: Among the 155 included studies, the case reports, review articles, and preclinical studies were analyzed for background information. A meta-analysis was performed for 11 studies for one-piece implants. The results indicated that the MBL change after 1 year was 0.94 ± 0.11 mm, with a lower bound of 0.72 and an upper bound of 1.16. For the mid term, the MBL was 1.2 ± 0.14 mm with a lower bound of 0.92 and an upper bound of 1.48. For the long term, the MBL change was 1.24 ± 0.16 mm with a lower bound of 0.92 and an upper bound of 1.56. Conclusion: Based on this literature review, one-piece ceramic implants achieve osseointegration similar to titanium implants, with a stable MBL or a slight bone gain after an individual initial design depending on crestal remodeling. The risk of implant fracture is low for current commercially available implants. Immediate loading or temporization of the implants does not interfere with the course of osseointegration. Scientific evidence for two-piece implants is rare.

Purpose: To evaluate the influence on peri-implant soft and hard tissues of one-piece implants with a convergent hyperbolic profile collar placed at different depths with respect to the bone crest., Materials and Methods: Six dogs were included in the experiment. Three months after mandibular tooth extractions, two one-piece implants carrying a 2.8-mm-high convergent hyperbolic profile collar were placed in the alveolar crest with the coronal margin of the rough surface either 0.8 mm (test-1) or 1.8 mm (test-2) deeper with respect to the bone crest (Ct0). Two similar implants were instead placed flush to Ct0 as controls (control-1 and control-2, respectively). Healing screws were connected, and nonsubmerged healing was allowed. After 4 months, block sections were harvested, and histologic slides were prepared in a buccolingual plane., Results: In the histologic analyses, both the buccal crest and coronal level of osseointegration were located more coronally at the test compared to the control implants concerning the implant. However, the buccal bone crest with respect to Ct0 presented a loss of 0.8 ± 0.4 mm at the test-1 and 0.5 ± 0.4 mm at the control-1 implants (P = .028), and a loss of 2.0 ± 1.0 mm and 0.7 ± 0.4 mm at the test-2 and control-2 implants (P = .028), respectively. At the control implants, the collars were exposed above the peri-implant mucosa, while those of the test implants were not. However, the coronal level of the peri-implant mucosa with respect to Ct0 was located more apically at the test compared to the control implants., Conclusion: The placement of implants with a hyperbolic convergent profile collar in the subcrestal position resulted in higher buccal bone resorption and more soft tissue recession compared to the crestal implants with respect to the level of the bone crest at placement.

Titanium oral implants are still considered "state of the art" in implant dentistry, with well-documented survival rates. However, their grayish color and high prevalence of peri-implant infections have resulted in controversial discussion as to whether tooth-like-colored, metal-free zirconia ceramic implants provide sufficient potential to be considered equal regarding treatment outcomes. The present position paper has been composed upon invitation by the European Association of Osseointegration in order to provide an update on the current level of evidence regarding zirconia implants in clinical trials. To date, most available and scientifically documented zirconia implant systems are one-piece implants that require an experienced surgeon and prosthodontist due to the restricted flexibility in cases of compromised angulation or vertical positioning. Taking this limitation into account, there is evidence of a comparable outcome for one-piece zirconia implants compared to titanium implants for the fixed replacement of one to three missing teeth. In contrast, currently available clinical data evaluating two-piece zirconia implants with an adhesively bonded implant-abutment interface suggest an inferior outcome. Data evaluating the clinical applicability of screw-retained solutions, even if revealing sufficient fracture resistance in laboratory investigations, are still missing. High survival rates were reported for all-ceramic reconstructions supported by zirconia implants, but with increased technical complications; ie, fractures of the ceramic veneer in the case of bilayered restorations. Sufficient clinical evidence for recommending monolithic approaches is limited to single crowns.

Purpose: To compare the temperature changes during the setting process of two provisional crown materials, polymethyl methacrylate (PMMA)-based acrylic resin (Ac) and bis-acryl composite resin (Co), at the first thread surface of one-piece implants., Materials and Methods: Twenty-two 3.3-mm-diameter one-piece implants were divided into two groups according to the provisional restoration material. Implants were mounted on a Plexiglas apparatus. A K-type thermocouple was fixed at the most coronal thread. Baseline (Bl Temp) and maximal (Max Temp) temperatures of both groups were recorded during the curing process. Total heat flux (THF) at the implant surface and thermal amplitude (Temp-Amp) were calculated. Differences between groups were compared using a t test for unpaired observations., Results: Upon curing, a statistically significant increase in the Max Temp from the Bl Temp was detected in both groups, with a greater increase in the Ac compared with the Co group. The Temp-Amp and the THF were two times greater in the Ac group than the Co group., Conclusion: Significant heat is produced during the polymerization of PMMA-based resin and bis-acryl composite resin provisional crowns in one-piece implants. To decrease the risk of thermal challenge at the implant cervical aspect associated with restoration of immediately loaded implants, bis-acryl composite resin should be used.

Background: Accurate implant placement in the bone is key to successful implant treatment. Once inserted, it can be difficult to correct the orientation of the implant axis, especially of a one-piece implant. Prosthetic-driven digital implant planning in combination with fully guided implant surgery can offer additional safety in such cases., Case Presentation: The patient presented with a wide, edentulous interdental space extending from sites 13 to 16, which was to be restored with three one-piece zirconia implants supporting a zirconia fixed partial denture comprizing a cantilever to the mesial aspect. Digital planning based on DICOM (Digital Imaging and Communications in Medicine) and intraoral surface data was performed to ensure optimal positioning. Guided implant placement was executed using a contra-angle handpiece with special attachments and a compatible, sleeveless drill guide. Impressions of the implants for the final restoration were acquired using an intraoral scanner. Reflection-related errors were compensated for by using the given digital abutment geometry. The DICOM and STL datasets were superimposed and used as the basis for fabricating a monolithic zirconia restoration through a subtractive milling process. The final restoration was adhesively cemented., Conclusions: By using a prosthetic-driven implant planning strategy, it was possible to place the one-piece ceramic implants without an available implant manufacturer's guide-based solution. This was accomplished using a contra-angle surgical handpiece with special attachments and a compatible drill guide. This approach is particularly recommended for the placement of one-piece implants, which otherwise require irreversible abutment grinding for the adjustment of the implant axis orientation after placement. To increase the precision of the digital impressions of the implants, the ideal abutment geometry was imported and superimposed onto the scan data. The results demonstrate that the proposed method can dispense with the need for gingival retraction when acquiring impressions for implants of this type in the future.

The purpose of the current study was to determine the survival rates and to measure marginal bone changes and peri-implant conditions 8.5 years after placement of one-piece implants with an anodically oxidized surface (AOS). A total of 52 subjects who received a one-piece implant with an AOS using a flapless or flap protocol and completed a previous randomized clinical trial were contacted for a recall visit 8.5 years after implant placement (T 8.5 ). Implant success and survival rates, probing pocket depth (PPD), presence of bleeding on probing (BoP), papilla level, and incidence of complications and peri-implant disease were assessed by a single, blinded examiner. A second blinded examiner evaluated marginal bone level changes. Results for 8.5 years were compared to those at the time of implant placement, implant loading (0.5 year), and 1 and 1.5 years follow-up. The results based on 28 patients who attended the follow-up visit (half had flapless and half a flap protocol) showed a 100% implant survival rate and a 96.4% implant success rate 8.5 years after implant placement using one-piece implants, with no difference in survival and success rates between the flapless and the flap protocol. During the same follow-up period, a significant increase in crestal bone height from 1.5 to 8.5 years was observed. Analysis suggested decreasing mean levels of bone loss with time (P < .001). Moreover, there was 0.8 to 1.0 mm of bone loss through year 1.5, which decreased to 0.3 mm at 8.5 years (P < .05). There was no statistically significant difference in PPD or BoP over time. Similar mean levels of PPD were found in flap and flapless groups (mean [SD] = 2.4 [0.3] and 2.2 [0.4] mm, respectively [P = .18]), as well as similar rates of BoP (22.8% vs 17.9%, respectively). Papilla levels increased during the first year after implant loading. However, there was little additional change between 1.5 and 8.5 years. A total of eight fractured porcelain crowns and three crown loosenings were reported. One-piece implants with an AOS showed high survival rates and stable marginal bone and periimplant soft tissue levels regardless of whether a flapless or flap protocol was used.

Purpose: This prospective study was undertaken to evaluate the 10-year implant survival rate as well as bone remodeling for immediately loaded anterior mandibular implants., Materials and Methods: Patients with nonrestorable anterior mandibular teeth were enrolled. All mandibular teeth were extracted, and five rough-surfaced (titanium plasma spray) one-piece implants were placed, evenly spread between the mental foramina. All implants were immediately loaded with a provisional prosthesis. A definitive prosthesis was ., Results: Eight patients received 40 implants, 30 in extraction sockets and 10 in healed sites. All but two implants that did not achieve primary stability (35 Ncm) were immediately loaded. The progress of seven patients was evaluated after 10 years. The mean age at implant placement was 60 years, and the length of follow-up varied between 10.3 and 11.47 years. The results showed a 100% implant retention rate; however, clinically observed bone loss around two central implants led to consideration for future surgical intervention or removal. Average bone loss was < 1 mm, and little difference was noted between implants placed in healed sites and those placed in extraction sockets. Technical problems with the prostheses were confined to two patients; one patient had seven fractures and the other had one., Conclusion: Rough-surfaced implants placed in extraction sockets between the mental foramina and immediately loaded can be successful in the long term. Because only is recommended that this site be avoided when immediately loaded implants are to be used in the anterior mandible.

Purpose: The purpose of this study was to determine the prosthodontic outcomes of one-piece zirconia implants and their attachment systems in edentulous participants with maxillary and mandibular overdentures after 1 year of a randomized controlled trial., Materials and Methods: Random allocation of 24 edentulous participants (age range: 45 to 86 years) into titanium (control) or zirconia (test) groups using onepiece implants and a planned unsplinted prosthodontic design was performed. Four maxillary implants (one midpalatal; three anterior crestal) and three mandibular implants (one midsymphyseal; two bilateral distal) were conventionally loaded with the overdentures. Similar attachment systems were used throughout: ball abutment-type patrices (diameter: 2.25 to 3.1 mm as part of the one-piece implants) and custommade plastic matrices (with or without metal housings depending on the patrix size). Prosthodontic outcomes were documented during the first year of the clinical trial., Results: Following three deaths and two dropouts, there were 19 participants who were available at the 1-year recall. Of these participants, 3 had early maxillary implant failure and had to be converted to conventional maxillary complete dentures opposing mandibular implant overdentures. There were 79 maintenance events, 34 in the titanium (control) group and 45 in the zirconia (test) group. Patrix loss occurred as a result of three zirconia implant fractures (one mandibular and two crestal maxillary implants). Maintenance events were principally the replacement of matrices and overdenture fracture. Although relines and replacement overdentures also occurred, overall there were no significant differences in prosthodontic maintenance between the control and test groups. A six-field prosthodontic-success analysis table showed no statistically significant difference between the two groups; however, 50% of participants in each group were allocated to the retreatment (repair) field, which produced a low prosthodontic success rate., Conclusions: Removable overdentures can be used on both one-piece titanium and zirconia implants with these attachment systems, due to no difference in prosthodontic maintenance and success. Before recommending routine use of a "metal-free" overdenture treatment option in clinical practice, consideration must be given to the success of the implants themselves.

Purpose: To retrospectively evaluate the clinical performance of zirconia endosseous implants., Materials and Methods: Partially edentulous patients with adequate bone volume to fit yttria tetragonal zirconia polycrystal (Y-TZP) implants at least 3.5 mm wide and 8.0 mm long were included. Full-mouth probing pocket depth (PPDs) and percentage bleeding on probing (BOP) scores around teeth and implant(s) were assessed and compared. Marginal bone loss/gain relative to baseline was measured on intraoral radiographs, and the prevalence and quantities of seven periodontal bacteria were assessed around implants and teeth in the same patient., Results: Seventy-four consecutively treated patients with 121 zirconia implants (66 two-piece implants and 55 one-piece implants) were clinically evaluated after a mean observation period of 18 months. Three implants had failed and had been removed, for a cumulative implant survival rate of 96.5% (± 2.0%) after 3 years. The 118 surviving implants demonstrated healthy mucosal conditions, with low mean PPDs (1.8 ± 0.4 mm) and mean BOP scores (4.1% ± 4.2%). PPD and BOP were statistically significantly lower around implants than around teeth. BOP and PPD around implants and teeth were significantly correlated. Stable marginal bone levels were observed (mean bone loss of 0.1 ± 0.6 mm after 3 years). The frequency of isolation of all marker bacteria was similar at tooth and implant sites., Conclusion: Zirconia endosseous implants can achieve a 3-year implant survival rate in partially edentulous patients, similar to that of titanium implants, with healthy and stable soft and hard tissues.

This study aimed to histomorphometrically evaluate the soft tissue reactions of one-piece zirconia implants versus titanium implants in regard to their insertion depth. Four one-piece implants of identical geometry were inserted on each side of six mongrel dogs: an uncoated zirconia implant, a zirconia implant coated with a calcium liberating titanium oxide, a titanium implant, and an experimental implant made of a synthetic material. Using a split-mouth design, they were inserted in both submerged and nonsubmerged healing modes. After 4 months, dissected blocks were stained with toluidine blue to histologically assess the marginal portion of the implant mucosa, apical extension of the barrier epithelium, and margin level of bone-to-implant contact. The inflammation status at the crestal part of the implant was assessed as well. The histomorphology presented the typical soft tissue configuration of barrier epithelium and connective tissue near the bone-to-implant contact. Histomorphometrically, the length of the barrier epithelium did not differ significantly concerning material type or healing modality. Furthermore, the inflammation signs were higher with nonsubmerged implants. The submerged uncoated zirconia implants, however, showed few signs of inflammation. Within the limits of this study, it is concluded that uncoated and coated zirconia implants are capable of establishing sufficient soft tissue configurations that are comparable to those of titanium implants.

Purpose: The aim of this clinical investigation was to evaluate marginal bone remodeling and soft tissue health surrounding a novel one-piece implant system over a 3-year study period., Materials and Methods: Subjects missing at least one tooth in either arch were consecutively enrolled in this open prospective 3-year investigation. Five clinics were invited to participate. Strict inclusion and exclusion criteria were used. Marginal bone levels were evaluated using radiographs taken at implant insertion, 6 months, and annually thereafter. Plaque and bleeding indices were recorded at 3 and 6 months and 1 and 3 years following implant insertion. The shapes of papillae were evaluated at implant insertion with the provisional restoration in place, at the insertion of the definitive restoration, and at the 3-year follow-up, using Jemt's papilla index. Life tables and the Mann-Whitney U test were used for statistical analyses., Results: Fifty-six patients were restored with a total of 82 one-piece implants; 47 patients attended the 3-year appointment. One implant had to be removed 1 month postinsertion, giving a cumulative survival rate of 98.8% for the 3-year study period. Most bone resorption (mean, 1.19 ± 1.38 mm; n = 61) occurred during the first year of function, while there was minimal change in mean marginal bone levels between 1 and 3 years (-0.07 ± 1.07 mm; n = 58). Normal peri-implant mucosa was registered for more than 81% of the sites, and no visible plaque was registered for more than 54% of the sites., Conclusion: This prospective 3-year multicenter study showed stable marginal bone levels, good soft tissue health, and a high implant survival rate, supporting the hypothesis that the presented one-piece implant system has the capacity to maintain both hard and soft tissues after the first year of initial bone remodeling.

Purpose: The aim of this article was to evaluate the effectiveness of various implant neck configurations in the preservation of marginal bone level as well as to identify the available scientific evidence., Materials and Methods: Online and hand searches of the literature published from 1976 through 2009 were conducted to identify studies dealing with modifications in the implant neck area and marginal bone loss for at least a 5-year observation period. The search terms that were used, alone or in combination, were "implant neck," "marginal bone loss," "neck design," "bone resorption," "bone remodeling," and "implant collar." Relevant studies were selected according to predetermined inclusion and exclusion criteria., Results: The initial search yielded 3,517 relevant titles and revealed eight different implant neck configurations and/or methods suggested for the preservation of marginal bone. These methods included changes in implant neck length and design, implant surface characteristics, implant diameter, and/or insertion depth; the addition of microthreads; the use of one-piece implants; and the concept of platform switching. After subsequent filtering, 20 studies were finally selected and involved the following methods: the use of microthreads (1 study); modifications in implant surface characteristics (11 studies), implant diameter (4 studies), or insertion depth (2 studies); the use of one-piece implants (3 studies); and platform switching (1 study). Because of the heterogeneity of the studies, it was not possible to analyze the data statistically. No evidence was found regarding the effectiveness of any specific modification in the implant neck area in preserving marginal bone or preventing marginal bone loss., Conclusion: The current literature provides insufficient evidence about the effectiveness of different implant neck configurations in the preservation of marginal bone. Long-term randomized controlled clinical trials are needed to elucidate the effects of such modifications.

Purpose: The aim of this retrospective analysis was to report on the clinical outcome of immediate provisionalization using one-piece narrow-diameter implants., Materials and Methods: The dental records of patients who received narrow implants were reviewed. Narrow-diameter (3.0-mm) one-piece implants were used to support restorations of missing maxillary lateral incisors and mandibular incisors. All implants were placed in a one-stage procedure according to the protocol recommended by the manufacturer, with immediate placement of provisional restorations. Following an average healing period of 3 months in the mandible and 5 months in the maxilla, the definitive prostheses were fabricated. The survival rate of the implants was analyzed, and radiographic evaluation was performed. RESULTS. Thirty-six patients (20 men and 16 women), aged from 42 to 72 years (average age of 53 years), were treated with 62 one-piece narrow implants. A success rate of 100% was observed over a period up to 33 months (mean, 23 ± 4.3 months). Among these, 8 implants were placed in maxillary lateral incisor positions and 54 implants were placed in mandibular incisor areas. Forty-four implants supported fixed partial prostheses, and 18 implants supported single crowns. The majority of the implants were 15 mm in length. Mean marginal bone loss at the 12-month follow-up visit was 0.53 ± 0.37 mm (range, 0 to 1.4 mm)., Conclusions: The results obtained in this retrospective analysis suggest that the one-piece narrow-diameter implant can predictably restore missing maxillary lateral incisors and mandibular incisor with narrow interdental spaces and labiolingual widths.

Purpose: To investigate the peri-implant stress fields generated from four different implant-abutment interfaces under axial loading applied at the center of the implant and several millimeters away from the implant center via photoelastic analysis., Materials and Methods: Similar unthreaded and cylindric implants and abutments were fabricated and embedded in photoelastic resin with four different implant-abutment interfaces: external hex, internal hex, internal taper (11.5 degrees), and solid connection to the abutment (one piece). The samples were submitted to vertical compressive loads; one was applied at the implant center (1.5 kg; centered load), and the other was applied 6.5 mm away from the center, 4.4 mm from the outside of the outer aspect of the implant (0.75 kg; off-centered load). The maximum shear stresses were determined and observed at 46 points around the implants under the centered load and at 61 points under the off-center load in the photoelastic models. Graphics describing the maximum shear stress (y-axis) and the analyzed points (x-axis) were obtained, and areas under the curves were calculated., Results: The centered loading (all points) resulted in small differences. The lowest amounts of stress were observed for the internal-taper implants, and values were minimally greater (0.4% to 3.3%) for the other implants. No statistically significant differences were found between groups for the centered load in any area. Under an off-center load, the internal-hex implants presented the least stress (all points). For off-center loading, the internal-hexagon implants differed significantly from the external-hex and one-piece implants and displayed the lowest stress levels., Conclusion: Under an off-center load, the internal-hex interfaces presented the lowest stress concentrations, internal-taper interfaces presented intermediate results, and one-piece and external-hex implants resulted in high stress levels. Centralized axial loads produced similar results.

This study compared the dimensions of the peri-implant soft tissues around immediately and early loaded one-piece implants as well as conventionally loaded one-piece implants. Comparisons of the peri-implant soft tissue dimensions were made among four different loading periods. Forty-eight titanium sandblasted/acid-etched implants were placed in four foxhounds. The implants were placed at four time periods in groups of three. The first group (A) had implants placed 3 months before the placement of restorations. Further groups of three implants each were placed at 21 days (group B), 10 days (group C), and 2 days (group D) before restoration. Three months after abutment connection, all dogs were sacrificed. Histometric analysis of the undecalcified histologic sections included dimensional measurements of the sulcus depth plus junctional epithelium, the connective tissue contact area, and recession measured from the interface to the gingival margin. No statistically significant differences were observed among the four groups. The data suggest that the dimensions of the peri-implant soft tissues around immediately and early loaded one-piece implants are similar to those around conventionally loaded one-piece implants and comparable to the dimensions of the biologic width around natural teeth.

Consecutively restored scalloped dental implants were evaluated radiographically and clinically. Radiographic evaluation of 16 two-piece scalloped implants and 9 one-piece scalloped implants revealed enhanced interproximal bone levels versus a nonscalloped conventional flat-top implant design. Based on the Jemt system for interproximal soft tissue level evaluation, 78% of the two-piece implants scored a 3 and 22% scored a 2, and 89% of the one-piece implants scored a 3 and 11% scored a 2. Enhanced interproximal tissue preservation from scalloped implant designs may lead to more predictable esthetic dental implant restorations in the anterior maxilla.