Assessment of the changes in retention and surface topography of attachments for maxillary 4-implant-retained overdentures.

STATEMENT OF PROBLEM: Restoring the edentulous maxilla with an implant-retained overdenture (IRO) can present a challenge because of increased implant divergence and the added wear of the implant abutments and attachments. However, knowledge pertaining to the degree of implant divergence and its effects on the wear pattern of the implant attachments is lacking. PURPOSE: The purpose of this in vitro study was to investigate the change in the retention and wear characteristics of unsplinted abutments and attachments when used to retain a maxillary 4-implant palateless complete removable overdenture with different implant angulations. MATERIAL AND METHODS: Three groups of specimens of 0-, 15-, and 30-degree implant angulations were evaluated, each with 7 specimens. The retention of specimens was recorded after aging cycles equivalent to 1, 2.5, and 6 years of use. The surface of the attachments was examined with light and scanning electron microscope (SEM). RESULTS: Increasing the interimplant divergence improved the initial retention. After 1 year of use, retention of the 15- and 30-degree groups was significantly higher than that of the 0-degree group (P<.05). No significant difference in retention was found between the 15- and 30-degree groups (P>.05). After 2.5 and 6 years of use, no significant difference in retention was noted between groups (P>.05). Under light and SEM examination, the wear of the abutments and attachments was related to the interimplant divergence. CONCLUSIONS: The initial retention of single attachments increased significantly as the implant divergence increased. The retention of the 15- and 30-degree groups was significantly higher than that of the 0-degree group after 1 year of use. No significant difference in retention was found after 2.5 and 6 years, regardless of implant angulation.

Immediate versus delayed temporization at posterior single implant sites: A randomized controlled trial.

AIMS: We conducted a randomized controlled trial to assess the clinical outcomes of two loading protocols involving either immediate or delayed prosthetic temporization of single implants placed at posterior, healed sites. MATERIALS AND METHODS: Forty-nine patients in need of single implants at premolar or molar sites were randomized to receive a temporary crown either immediately after implant placement or 3 months later. Randomization was stratified by sex, implant location (premolar/molar) and arch (maxilla/mandible). Final implant screw-retained zirconia crowns with angulated screw channels were delivered at 5 months after surgery. Radiographic bone levels (primary outcome), peri-implant mucosal margin levels and peri-implant probing depths were recorded at baseline, 6 and 12 months after surgery. RESULTS: Both treatment arms showed similar patterns of soft tissue and bone re-modelling from the implant platform over 12 months [mean bone level change 1.6 mm (SD 1.0 mm) in the delayed, and 1.2 mm (SD 1.3 mm) in the immediate temporization group], with the majority of changes occurring within the first 6 months. CONCLUSIONS: Immediate or delayed temporization of single implants placed at posterior healed sites resulted in largely similar 1-year outcomes with respect to peri-implant bone levels and soft tissue changes.

Prosthetically Driven Therapy for a Patient With Systemic Lupus Erythematosus and Common Variable Immunodeficiency: A Case Report.

Patients who have systemic diseases in conjunction with severely resorbed maxillary and mandibular bone present challenges for dental implant therapy and rehabilitation. This case report describes the interdisciplinary comprehensive treatment completed on a patient with systemic lupus erythematosus (SLE) and common variable immunodeficiency (CVID). Patients with these systemic conditions present a multifactorial challenge for dental treatment due to advanced carious lesions, missing teeth, lack of adequate bone quality and quantity, as well as secondary effects of their medications. The sequence of treatment presented allowed for the necessary case control to ensure successful, predictable reconstruction of the edentulous patient with limited bone available for implant placement. For this patient, we used a combination of autogenous iliac bone graft, bilateral maxillary sinus lifts with BMP-2, transitional implants, and dental endosseous root form implants. Digital dentistry aided in designing the final implant supported fixed restorations. Transitional implants eliminated the need for tissue-borne prostheses, avoiding pressure to the graft and implants. Digital dentistry allowed for prosthetically driven implant placement and a functional, esthetic result. The techniques and staging presented for implant placement and rehabilitation can be used for other patients presenting with similar challenging conditions.

Various Surface Treatments to Implant Provisional Restorations and Their Effect on Epithelial Cell Adhesion: A Comparative In Vitro Study.

PURPOSE AND OBJECTIVE: The aim of this in vitro study was to investigate the ability of epithelial cells to attach to or proliferate on various mechanical or chemical surface treatments of an implant provisional material. MATERIALS AND METHODS: Polyethyl methacrylate discs 10 mm in diameter and ∼0.2 to 0.75 mm in width were used in the study. Experimental discs were treated with either a mechanical (pumice, varnish for shine, or high polishing) or a chemical agent (alcohol, chlorhexidine, or steam) to provide cleaning and/or polishing. Using primary human epidermal keratinocytes, experiments were performed to test the adhesion or proliferation of cells on the discs with various surface treatments. RESULTS: Scanning electron microscope analysis, rhodamine staining, and cell counting using a hemocytometer corroborated all findings and illustrated that the highest cell adhesion was found to be in the smooth surface treatment groups and the poorest adhesion was found to be in the rough surface groups and chemical treatment group. CONCLUSION: Within the limitations of this study, the following clinical protocol is recommended for finishing, polishing, and disinfecting implant provisional restorations: coarse, medium, fine pumice → high polishing (if desired) → steam. It is recommended to avoid applying varnish in the perimucosal area near the epithelium. This study could establish the most appropriate way to handle provisional restorations in the peri-implant sulcus for improved soft tissue health, esthetics, and long-term stability.

A prospective clinical trial to assess the optical efficacy of pink neck implants and pink abutments on soft tissue esthetics.

OBJECTIVE: The purpose of this prospective, randomized, controlled, multicenter clinical study was to analyze the optical effects of an anodized pink colored implant shoulder/abutment system in the peri-implant mucosa of immediately placed dental implants. MATERIALS AND METHOD: Forty subjects with a restoratively hopeless tooth in the maxillary esthetic zone, were recruited and randomized to receive either a pink-neck implant, or a conventional gray implant. All patients received an immediate implant and immediate provisional and two identical CAD/CAM titanium abutments with different surface colors: pink and gray, and one zirconia all-ceramic crown. The color of the peri-implant mucosa was measured using a dental spectrophotometer and analyzed using CIELAB color system. RESULTS: The overall color difference between the peri-implant mucosa with a pink abutment and a gray abutment was ΔE = 4.22. Patients with gray implants presented a color change of ΔE = 3.86-4.17 with this abutment change, while patients with pink implants had a color change of ΔE = 3.84-4.69. The peri-implant mucosa with a pink abutment was significantly more red when compared with a gray abutment (P ≤ .01). CONCLUSIONS: When a pink abutment was used, there is a significant color change of the peri-implant mucosa that is above the detectable color threshold. CLINICAL SIGNIFICANCE: Esthetic outcomes are important for the success of implant treatment of maxillary anterior implants. The phenomenon of the gray color of a dental implant and abutment shining through the peri-implant mucosa has been documented in the literature. The objective of this study was to assess the optical effect of an anodized pink-neck implant and a pink abutment on the color of peri-implant mucosa. This study demonstrates that using pink-neck implant and a pink abutment would contribute positively to the overall esthetic outcome for an anterior implant.

Clinical and patient-reported outcomes after recession coverage using modified vestibular incision subperiosteal tunnel access with a volume-stable collagen matrix as compared to a coronally advanced flap with a subepithelial connective tissue graft.

PURPOSE: Coronally advanced split-or full-thickness (CAST or CAFT) flaps in combination with subepithelial connective tissue grafts (SCTGs) are commonly used in root-coverage procedures despite postoperative pain and bleeding from the graft donor site. Therefore, the modified vestibular incision subperiosteal tunnel access procedure (VISTAX) uses a novel collagen matrix (VCMX) instead of autogenous tissue to address the limitations associated with autogenous tissue grafting. This retrospective study compared the clinical outcomes of VISTAX to the results obtained after using a CAST or CAFT flap in combination with SCTG for root coverage. METHODS: Patients with single or multiple adjacent recession I/II defects were included, with 10 subjects each in the VISTAX, CAFT, and CAST groups. Defect coverage, keratinized tissue width, esthetic scores, and patients' perceived pain and dentinal hypersensitivity (visual analogue scale [VAS]) were assessed at baseline, 3 months, and 6 months. RESULTS: All surgical techniques significantly reduced gingival recession (P<0.0001). Defect coverage, esthetic appearance, and the reduction in dentinal hypersensitivity were comparable. However, the VAS scores for pain were significantly lower in the VISTAX group than in the CAFT and CAST groups, which had similar scores (P<0.05). Furthermore, the clinical results of VISTAX and CAFT/CAST generally remained stable at 6 months. CONCLUSIONS: The clinical outcomes of VISTAX, CAFT, and CAST were comparable. However, patients perceived significantly less pain after VISTAX, indicating a potentially higher patient acceptance of the procedure. A prospective trial with a longer follow-up period and a larger sample size should therefore evaluate VISTAX further.

Evaluation of Dimensional Changes and Ridge Contour Around Ovate Pontics Inserted Immediately After Extraction with Alveolar Ridge Preservation in the Esthetic Zone.

Alveolar ridge preservation (ARP) is indicated to attenuate anatomic and physiologic changes following tooth extraction. A properly contoured ovate pontic placed immediately into an extraction socket may be adequate to maintain alveolar ridge architecture for improved esthetic results. This prospective clinical study evaluated the ability of immediately placed ovate pontics in conjunction with ARP to attenuate postextraction tissue dimensional changes in the esthetic zone and maintain alveolar ridge contour. Ten patients (11 sites) completed the study. All subjects received a combination of socket grafting with allogeneic particulate graft material and socket sealing with an ovate pontic provisional restoration. A set of clinical linear and volumetric outcomes were assessed after a 6-month healing period. At 6 months postoperative, the linear measurements for the mean ridge dimensional loss were 0.9 ± 0.6 mm (range: 0.2 to 1.8 mm) in height and 1.4 ± 0.6 mm (range: 0.1 to 2.4 mm) in width. The mean volumetric tissue loss observed was 24.4 ± 15.4 mm3 (range: 2.6 to 50.1 mm3) at 3 months postoperative and 32.2 ± 14.2 mm3 (range: 3.8 to 50.5 mm3) at 6 months postoperative. Resorption pattern assessment showed the overall cervical area to have less resorption than the apical areas at 6 months postoperative, with the least amount of resorption in the midbuccal cervical section. When compared to the data of a previous pilot study, no statistically significant difference was seen between the dimensional losses when using ovate pontics with and without ARP. This may be evidence that the use of an ovate pontic provisional restoration immediately after extraction effectively attenuates postextraction dimensional changes.

A Retrospective, Multicenter, Cross-Sectional Case Series Study Evaluating Outcomes of CAD/CAM Abutments on Implants from Four Manufacturers: 4-Year Mean Follow-up.

PURPOSE: To evaluate the clinical, radiographic, and prosthetic outcomes of a single custom CAD/CAM abutment system on implants from four manufacturers, with a mean clinical service of 4 years in a retrospective, multicenter case series study. MATERIALS AND METHODS: Adult subjects (n = 142) previously restored with titanium or gold-shaded titanium nitride custom CAD/CAM abutments (Atlantis, Dentsply Sirona; n = 259) connected to implants from four different manufacturers (Dentsply Sirona Implants [AT], Biomet 3i [BM], Nobel Biocare [NB], Straumann [ST]), irrespective of implant-abutment interface, and replacing one or more teeth in any position were recalled for a single-visit examination by calibrated investigators at six university clinics. The primary outcomes evaluated included abutment success and survival; secondary outcomes included assessment of papillae fill, probing pocket depth (PD), bleeding on probing (BOP), marginal bone levels (MBLs), and patient-reported outcome measures (PROMs). RESULTS: Two-hundred fifty-five (98.5%) abutments supported cement-retained restorations, and four (1.5%) abutments supported screw-retained restorations. Forty-two patients had 64 AT implants (25%), 31 patients had 61 BM implants (24%), 26 patients had 50 NB implants (19%), and 43 patients had 84 ST implants (32%). The overall implant-CAD/CAM abutment success rate was 92.66% (95% CI: 88.78%, 95.53%) for all implants examined, and the survival rate was 98.84% (95% CI: 96.65%, 99.76%) for all implants evaluated. The Jemt papillae index demonstrated a minimum of at least 50% to complete fill of the interproximal papillae in 65.0% of sites. PDs had a median value of 3.0 mm, and BOP was present on 19% of abutment surfaces. Mean MBL changes from the time of placement to exam were -0.24 ± 0.99 mm (-4.9 to 2.3; P = .058) for mesial sites and -0.32 ± 0.96 mm (-4.9 to 2.1; P = .000) for distal sites. PROMs expressed 93% of patients reporting good to very good masticatory function, 97% of patients reporting being satisfied or very satisfied with their esthetic outcomes, and 94% of patients indicating that they were satisfied or very satisfied with their overall implant-restorative outcomes. CONCLUSION: This retrospective, multicenter clinical study of FDA 510k-approved titanium CAD/CAM abutments of a single manufacturer on multiple implant systems demonstrated high levels of success and survival as well as stable peri-implant tissue outcomes, reflected by overwhelmingly positive PROMs.

Evaluation of a one-piece milled zirconia post and core with different post-and-core systems: An in vitro study.

STATEMENT OF PROBLEM: One-piece milled zirconia posts and cores present an esthetic option as foundation restorations for ceramic crowns. To date, dimensional fit and load capacity of 1-piece zirconia posts and cores have not been determined. PURPOSE: The purpose of this study was to evaluate the accuracy of fit of milled zirconia posts and cores and to compare the shear strength with other post-and-core systems. MATERIAL AND METHODS: Eighty-five maxillary central incisors and canines received endodontic treatment and were divided into 5 groups (n=17) as follows: cast gold post and core (Au) as control, 1-piece milled zirconia post and core (Zr), prefabricated zirconia post with heat-pressed ceramic core (Zr/Cer), titanium post and composite resin core (Ti), and combined fiber/zirconia post with composite resin core (Fiber/Zr). The posts and cores were cemented with dual-polymerized composite resin cement (Multilink). Zirconia copings were made for each specimen, cemented, and loaded to failure. Fracture loads and modes of failure were recorded. Fracture loads were compared with a linear model. Differences in the mean marginal gap distance between the post-and-core patterns and the adjusted milled zirconia posts and cores were analyzed with a paired t test (alpha=.05). RESULTS: A significant difference was found in the marginal gap distance of group Zr (P<.001), compared with the marginal gap distance of the acrylic resin patterns. Mean loads to failure were highest for the Fiber/Zr group in comparison with custom-made milled zirconia posts and cores (P<.001). CONCLUSIONS: All systems evaluated presented sufficient mean load-to-failure values for anterior tooth restorations, including the recently developed 1-piece milled zirconia post and core.

Evaluation of Horizontal and Vertical Buccal Ridge Dimensional Changes After Immediate Implant Placement and Immediate Temporization With and Without Bone Augmentation Procedures: Short-Term, 1-Year Results. A Randomized Controlled Clinical Trial.

This prospective randomized controlled clinical trial aimed to compare changes in the horizontal and vertical soft tissue and the alveolar ridge dimension over the course of 12 months following immediate implant placement and temporization with or without simultaneous augmentation with a deproteinized bovine bone mineral with 10% collagen (DBBM-C). Thirty-two patients with a hopeless maxillary anterior tooth and fully intact sockets received an immediate implant and provisional or custom healing abutment after a flapless extraction. Patients were randomized to a control group (n = 16), which received no graft, or to a test group (n = 16), which received DBBM-C grafts. Horizontal and vertical soft tissue changes as well as soft tissue thickness were compared digitally between groups on casts obtained from impressions made at baseline and 3, 6, and 12 months. The test group showed less horizontal dimensional change than the control group; however, the change between the two groups was not statistically significant. Vertical dimensional soft tissue changes from baseline to 12 months showed a statistically significant difference at the distal papilla, favoring the test group. No statistically significant difference was observed for vertical changes between both groups at mesial papillae and midbuccal soft tissue; however, the test group showed lower values overall. No statistically significant differences in soft tissue thickness between groups were detected. Immediate implant placement and temporization with and without adding DBBM-C demonstrate favorable clinical outcomes regarding horizontal and vertical soft tissue changes. Both groups showed loss of tissue volume. Adding DBBM-C in the gap of immediately placed implants slightly lowered the change in tissue parameters, which was not statistically significant, for the first 12 months after implant placement.

Comparison of Peri-implant Soft Tissue Color with the Use of Pink-Neck vs Gray Implants and Abutments Based on Soft Tissue Thickness: A 6-Month Follow-up Study.

PURPOSE: To compare the optical effects of an immediately placed anodized pink-neck implant and abutment vs a conventional gray implant and abutment in relation to soft tissue thickness 6 months after the restoration was completed. MATERIALS AND METHODS: Forty patients with a hopeless maxillary anterior tooth received an immediate implant and an immediate provisional or custom healing abutment after flapless extraction. Participants were randomized to receive either a conventional titanium implant (control) or a pink-neck implant (test). All patients then received two identical CAD/CAM titanium abutments (one conventional gray, delivered first, and one anodized to appear pink, delivered 3 weeks after) and a zirconia crown. A spectrophotometer was used to record the color of the peri-implant mucosa and gingiva 3 weeks after delivery of each abutment and 6 months after the final restoration was delivered. The color difference between the two sites was calculated (ΔL*, Δa*, Δb*), and correlations with soft tissue thickness, change in ridge dimension, and implant position were assessed. RESULTS: Irrespective of the randomization group, changing the abutments from gray to pink showed a change in color between the peri-implant mucosa and the natural gingiva. Patients with a thin gingival biotype showed a statistically significant color change (P = .00089) in the a* axis, meaning that the gingiva appeared more pink (Δa*). No significant correlation between the soft tissue color and buccolingual collapse, vertical recession, or implant position was observed in either group. CONCLUSION: The difference in color observed between the peri-implant mucosa and the gingiva was considerable in all groups. Anodized pink implants and abutments could reduce the difference in the red aspect (Δa*) of the peri-implant mucosa compared to the adjacent gingiva in patients with a thin biotype.

Comparison of the Color Appearance of Peri-implant Soft Tissue with Natural Gingiva Using Anodized Pink-Neck Implants and Pink Abutments: A Prospective Clinical Trial.

PURPOSE: The aim of this study was to assess the visual effects of pink-neck implants and pink abutments with respect to the color of natural gingiva. The distribution pattern and magnitude of CIELAB color difference coordinates were studied. MATERIALS AND METHODS: Forty subjects with a tooth in the maxillary esthetic zone deemed hopeless were recruited. Patients were randomized to either a conventional gray implant or a pink-neck implant. The hopeless tooth was removed and patients received an immediate implant along with an immediate customized provisional prosthesis. The provisional was maintained for 3 months to allow for complete healing of the implants. Two identical CAD/CAM titanium abutments only differing in color (gray and pink) were fabricated along with an all-ceramic zirconia crown. The gray abutment was delivered first with a zirconia crown, and it was replaced with the pink abutment 3 weeks later. Three weeks after insertion of each abutment with the zirconia crown, a spectrophotometer was used to collect the color of the peri-implant mucosa and natural gingiva, so the difference between the two sites could be calculated (ΔL* [difference in lightness], Δa* [difference in green-red axis], Δb* [difference in blue-yellow axis]). The natural gingiva measured was the gingiva of a contralateral or adjacent unrestored tooth. The effect of implant color and abutment on the color difference between peri-implant mucosa and natural gingiva was investigated with a linear regression model using a generalized estimating equation (GEE) approach. RESULTS: Raw data demonstrated statistically insignificant smaller ΔL*, Δa*, Δb* between peri-implant soft tissue and natural gingiva when the implant was pink versus gray. Further, there were statistically insignificant smaller ΔL* and Δb* between peri-implant soft tissue and natural gingiva when the abutment was pink versus gray. Δa* between peri-implant soft tissue and natural gingiva was significantly smaller when using a pink abutment regardless of the implant type (P < .05). CONCLUSION: Using an anodized pink abutment and/or a pink-neck implant minimizes the color difference observed between the peri-implant mucosa and the natural gingiva in the redness spectrum. These advances in technology assist in helping the peri-implant mucosa appear more natural by minimizing the color variance.

Changes of the alveolar ridge dimension and gingival recession associated with implant position and tissue phenotype with immediate implant placement: A randomised controlled clinical trial.

PURPOSE: This prospective, randomised, controlled clinical trial evaluated the relationship between alveolar ridge dimensional change and recession with the implant position (horizontal and vertical) and tissue phenotype in immediately placed and provisionalised implants without the use of bone grafting. MATERIALS AND METHODS: Patients (n = 40) with a hopeless maxillary anterior tooth received an immediate implant and immediate provisional or customised healing abutment after flapless extraction. Implants were finally restored 3 months after placement and followed up for 6 months after delivery of the restoration. The alveolar ridge dimensional change and recession were measured using cone beam computed tomography (CBCT) scans and digitalised dental casts. Alveolar contour changes were correlated to implant position and tissue phenotype. RESULTS: The tissue phenotype showed no significant correlation to the alveolar ridge dimensional change. At 6 months, the average alveolar ridge dimensional change was approximately 0.7 mm in the buccolingual dimension independent of tissue phenotype. A statistically significant difference was observed on the recession values comparing tissue phenotypes, with more recession observed in the thin phenotype (1.96 mm) than in the thick phenotype (1.18 mm). A significant correlation was observed between horizontal implant position and buccolingual alveolar ridge change. A positive correlation was observed between the horizontal implant position and the dimensional change measured in the casts at the level of the free gingival margin. A statistically significant negative correlation was observed between the horizontal implant position and the resorption measured by the CBCT scans. CONCLUSIONS: Patients with thin tissue phenotype had a more marked recession. The horizontal implant position showed a relationship to the alveolar ridge dimensional changes observed. The greater the buccal gap distance between the implant and the buccal plate, the lesser the radiographic changes observed in the alveolar bone, however, the greater the changes observed in the buccal aspect of the casts at the level of the free gingival margin.

Fabrication of a custom abutment for a wide-diameter implant in a situation with limited interocclusal space.

This article illustrates a technique to solve the esthetic and functional challenges of restoring implants in situations with limited interocclusal clearance. As manufactured, some wide implants lack a gold cylinder abutment that attaches directly to the implant. Instead, an intermediate abutment is provided with the system. However, with limited interocclusal space, it is not feasible to restore an intermediate abutment due to the increased restorative space required. This article describes a technique to fabricate a customized abutment that directly connects to a wide-diameter implant, resulting in a functional and esthetic restoration.

Changes in Ridge Dimension with Pontics Immediately Placed at Extraction Sites: A Pilot Study.

The aim of this prospective clinical study was to evaluate dimensional changes following immediate placement of a fixed ovate pontic provisional restoration into an intact extraction socket without grafting. The mean buccolingual dimensional change at 1 month was 0.51 ± 0.48 mm and 0.93 ± 0.55 mm at 3 months. The mean incisoapical dimensional change at 1 month was 0.68 mm ± 0.19 mm, and at 3 months, 1.64 ± 1.35 mm. The dental literature reports dimensional change of 3 to 5 mm in width and 1 to 4 mm in height for ridges with no treatment following extraction. This study provides validation for the use of ovate pontics in the preservation of tissue contour. Further research is needed to determine whether placing a graft into the socket with placement of an ovate pontic will decrease dimensional changes after extraction.

Histomorphometric Results of a Randomized Controlled Clinical Trial Studying Maxillary Sinus Augmentation with Two Different Biomaterials and Simultaneous Implant Placement.

PURPOSE: Maxillary sinus augmentation has been a predictable procedure. However, in-depth analysis of tissue healing after sinus grafting with simultaneous implant placement is limited. This study aimed to compare histologic outcomes after sinus grafting with a synthetic bone graft compared with a xenograft. MATERIALS AND METHODS: A randomized controlled split-mouth study was conducted to compare bone formation around microimplants (2.00 mm, Dentium) placed at the time of maxillary sinus augmentation with a synthetic material (Osteon, Dentium) (OST) and deproteinized bovine bone (Bio-Oss) (BIO) as the control group. Four microimplants per subject (n = 13) were placed bilaterally for intrasubject comparison (two implants per side/patient). Bone cores with osseointegrated microimplants were harvested for histomorphometric analysis 6 to 8 months after sinus augmentation surgery. RESULTS: Histologic analysis revealed newly formed bone deposited on the microimplant surface and bridging to bone graft material in both groups. Further, there was no histologic evidence of signs of inflammation in all specimens. In general, bone-to-implant contact was comparable and ranged from 6.1% to 67.0% with a mean of 38.4% ± 11.61% in OST and from 10.5% to 57.0% with a mean of 34.58% ± 12.55% in BIO. However, a significantly higher percentage of bone-to-implant contact in the first four threads of the grafted area was noted in OST compared with BIO (P = .016). CONCLUSION: The synthetic OST was found to be equivalent to BIO in new bone formation and clinical success after sinus augmentation in conjunction with microimplant placement. Although there are some statistically significant differences in the histologic outcomes, the clinical relevance of these needs to be further evaluated. Nevertheless, the findings of this study indicate that this synthetic alloplast would be a viable alternative to an allograft material.

Multicenter Clinical Randomized Controlled Trial Evaluation of an Implant System Designed for Enhanced Primary Stability.

PURPOSE: This intention-to-treat (ITT) non-inferiority multicenter study was performed to evaluate implant system design, surgical and prosthetic aspects, and the effect on marginal bone levels of two related implant systems. Implant design alterations consisted of modifications in implant body shape and abutment connections. Drilling procedures and drill design were adapted to the implant design. MATERIALS AND METHODS: Five clinics participated in this study; all had institutional review board approval. Two versions of the implant system were used: test and predicate. One hundred twenty partially dentate subjects with healed sites were randomized to either test or predicate implants. Fifty-nine subjects received 79 test implants and 61 received 87 predicate implants. Bone classification, insertion torque values (ITV), and the surgeon's perception of primary stability were recorded. Definitive restorations with a titanium abutment were made approximately 6 to 8 weeks following implant placement. All restorations were cement retained. Marginal bone levels were evaluated on radiographs at implant placement, at restoration, and at 6 and 12 months postloading. RESULTS: Most subjects received one implant placed in the premolar or molar area (95% of sites). Fifty-three percent of the implants were placed in the maxilla. Median ITV at placement was 31 ± 13 Ncm for the test system and 22 ± 9 Ncm for predicate system, respectively. Time to loading was similar (test, 63.1 ± 24.8; predicate, 62.9 ± 26.9 days). Mean marginal bone loss 12 months after functional loading was 0.07 ± 0.73 mm in the test group and 0.03 ± 0.84 mm in the predicate group, with no statistically significant difference (P = .6895). Five implants were lost (four test, one predicate) from implant placement, all within the first 8 weeks following placement; none were restored. The 1-year postloading cumulative implant survival rate was 94.9% (73 implants at risk) for the test system and 98.9% (84 implants at risk) for the predicate system. CONCLUSION: Treatment with the test implant system, utilizing its bone classification for guidance regarding drilling protocol, resulted in enhanced implant stability. Marginal bone levels were stable 12 months after functional loading.