Clinical implant dentistry and related research最新文献

Purpose: To evaluate the mid-term clinical and radiographic results of immediate fixed full-arch prosthesis supported by two anterior axial and two posterior trans-crestally placed tilted implants in patients with severely atrophic posterior maxilla.

Materials and methods: Patients with posterior maxillary ridge less than 4 mm high and 3 mm wide were rehabilitated with an immediate fixed provisional prosthesis supported by two anterior axially placed and two trans-crestal posterior tilted implants within 3 h after implant surgery. The final prosthesis, consisting of a CAD-CAM titanium framework and composite teeth was delivered 6 months later. Patients were scheduled for follow-up visits every 6 months to assess clinical and radiological parameters. Patients' satisfaction was assessed by a questionnaire up to 5 years.

Results: From April 2008 to May 2017, 56 implants (28 axial and 28 tilted) were inserted in 14 subjects (eight female and six male). The average bone loss for the anterior axial implants was 0.99 ± 0.19 mm at 1 year (n = 28 implants), 1.37 ± 0.31 mm at 5 years (n = 28), and 2.05 ± 0.32 mm at 10 years (n = 14). Only for three implants in two subjects the marginal bone loss was higher than 2 mm after 60 months. No implant was lost, and no prosthetic failure occurred after a mean follow-up of 125 months (range 79-186 months), leading to 100% implant and prosthesis survival rates. The upper 95% confidence limit of the failure rate was 23% and 6% at patient and implant level, respectively. High level of satisfaction was reported at 5-year follow-up.

Conclusion: Wider sample sizes will be required to determine whether the presented technique is a reliable treatment option for the immediate rehabilitation of the atrophic maxilla.

Introduction: Bidirectional vertical ridge augmentation in the posterior maxilla is very challenging.

Purpose: To evaluate the regenerative potential of micrografts, derived from periosteum or bone tissue, added to an anorganic xenograft in vertical reconstruction of the posterior maxilla, by a prospective, controlled study.

Materials and methods: After clinical selection and the analysis of CBCT scans, 24 posterior maxillary sites, in 19 patients, were treated by using Barbell Technique®. Sites requiring both inlay and onlay reconstruction were enrolled in the study. In the Control Group (CG, n = 8), a xenograft was used in the inlay site and for the onlay site, a 1:1 mix of xenograft and an autograft was used. In Test Group 1 (TG1, n = 8), both inlay and onlay sites were grafted with the xenograft associated with the micrografts derived from periosteum. In Test Group 2 (TG2, n = 8), both inlay and onlay sites were grafted with the xenograft associated with the micrografts derived from bone. Six months after the procedures, CBCT scans were obtained, and bone biopsy samples were harvested during implant placement surgery. The bone specimens were analyzed histomorphometrically, by measuring the percentages of vital mineralized tissue (VMT), non vital mineralized tissue (NVMT) and non mineralized tissue (NMT). Immunohistochemically, the levels of VEGF were categorized by a score approach.

Results: Histomorphometric analysis revealed, for the inlay grafts, no significant difference among the groups for VMT, NVMT and NMT. However, for onlay grafts, CG achieved a higher amount of VMT in comparison with TG2, and the opposite occurred for NMT values. In this regard, no statistical difference was observed between CG and TG1. Concerning immunohistochemistry, the VEGF values for CG and TG1 were slightly higher than those obtained by TG2 for both inlay and onlay grafts, but without statistical significance. CBCT analysis showed a similar level of gain for all groups, for both inlay and onlay bone augmentation sites. Clinically, one implant (in CG) within a total of 50 implants installed, had early failure and was replaced after 3 months. All patients received implant supported prosthesis.

Conclusion: This study indicated that the clinical use of micrograft derived from periosteum may have some potential to increase bone formation in onlay reconstructions, unlike the micrograft derived from bone tissue.

Purpose: The objective of this study was to assess the surface micro-roughness and abutment adaptation of selective laser melting (SLM) implant abutments in comparison to cast and machined implant abutments.

Methods: Forty abutment specimens were divided equally into four groups according to the fabrication technique as follows (n = 10), Machined Ti alloy abutments (Control), Cast CoCr abutments, SLM-CoCr abutments, and SLM-Ti alloy abutments. Forty internal connection implants (Ø 4.0 ×10 mm, Superline™, Dentium Co., Seoul, Korea) were mounted in clear acrylic resin. Fabricated abutments were assessed for surface micro-roughness using a 3D optical noncontact surface microscope. Vertical and horizontal adaptation of the abutment with implant interface was assessed by using Bruker micro-CT. Data was assessed using analysis of variance and Tukey post hoc comparison tests for all the variables except vertical misfit was assessed using Kruskal-Wallis test. Pearson correlation was used to assess dependence between independent variable (surface roughness) and dependent variables (Horizontal misfit and vertical misfit).

Results: SLM-Ti abutments showed significantly rougher surface (p < 0.05) among the study groups. While SLM-CoCr abutments were smoother than Cast abutments with mean Ra of 1.30 ± 0.11 and 1.58 ± 0.17 μm, respectively (p < 0.05). For abutment adaptation, SLM-Ti abutments showed the highest horizontal misfit among the groups (p < 0.05). While, SLM-CoCr abutments (29.24 ± 11.11 μm) showed comparable (p > 0.05) horizontal misfit results with Cast (26.08 ± 3.93 μm) and machined (26.45 ± 7.33 μm) abutments. Comparable (p > 0.05) vertical misfit values between Cast CoCr (487.01 ± 40.34 μm), SLM-CoCr (358.38 ± 114.93 μm) and SLM-Ti (299.85 ± 172.88 μm) abutments were observed. A positive correlation was found between the surface roughness of the mating surfaces and abutment adaptation.

Conclusion: SLM CoCr abutments exhibited low roughness and comparable abutment adaptation (vertically and horizontally) than cast (control) abutments. Therefore, SLM CoCr abutments should be clinically investigated as potential implant abutments for clinical use.

Objectives: This study investigated the accuracy of robotic computer-assisted implant surgery (r-CAIS) for immediate implant placement.

Methods: Twenty cases with 20 implant sites were selected based on predefined inclusion criteria. The preparation of the implant bed and implant placement followed the standardized dental implant robotic surgery protocol. Postoperative cone-beam computed tomography scans were conducted to assess possible discrepancies between actual and planned implant positions.

Results: The r-CAIS technology for immediate implant placement exhibited a mean global coronal deviation of 0.71 ± 0.27 mm (95% CI: 0.58-0.83 mm), a mean global apical deviation of 0.69 ± 0.26 mm (95% CI: 0.56-0.81 mm), and an angular deviation of 1.27 ± 0.47° (95% CI: 1.05-1.49°). A substantial number of deviations were observed buccally at both coronal (90%) and apical (95%) levels, with a consistent tendency for buccal deviation.

Conclusions: The r-CAIS technology proved a promising approach for immediate implantation in the anterior region, with satisfactory clinical outcomes. However, an optimized surgical protocol for r-CAIS technology is required for particular implant sites like extraction sockets or bone defects.

Aim: To evaluate the efficacy of guided bone regeneration (GBR) for the treatment of peri-implant dehiscence defects using a synthetic bone substitute (SBS) or a deproteinized bovine bone mineral (DBBM) as a bone substitute.

Methods: Patients with expected dehiscence defects following implant placement were randomized to use either SBS or DBBM together with a bioabsorbable collagen membrane over dehiscenced implant surfaces aimed for GBR. The changes in the bone defect size were measured before the GBR procedure and 6 months after implant placement at the re-entry surgery. Secondary outcomes included peri-implant health outcomes, implant cumulative survival rates, bone level changes, and patient-reported outcomes (PROMs) at prosthesis delivery and 1-year follow-up.

Results: Of the 49 included patients, 24 were treated with SBS and 25 with DBBM. In the SBS group, the defect height (DH) at implant insertion was 5.1 ± 2.6 mm and was reduced at re-entry to 1.3 ± 2.0 mm (74.5%). In the DBBM group, the respective changes in DH were 4.1 ± 1.7 mm and 1.5 ± 1.9 mm (63.4%). These differences were not statistically significant (p = 0.216). The complete defect resolution rate was also comparable in both groups without statistical difference (62.5% of patients (15/24) vs. 44% of patients (11/25)). Overall, the marginal bone levels remained stable during the 1-year follow-up in both groups.

Conclusion: The SBS is noninferior to DBBM for simultaneous GBR to implant placement at implant sites with buccal dehiscences in terms of defect resolution and evaluated secondary outcomes (KCT0008393 - this clinical trial was not registered before participant recruitment and randomization).

Objectives: This retrospective study aimed to evaluate the early and late implant failure rates of one-stage lateral sinus floor elevation (LSFE) and to identify the patient and implant-related risk factors associated with these failures.

Materials and methods: All patients treated with one-stage LSFE from January 2014 to December 2021 were evaluated for inclusion. A total of 618 patients with 936 implants met the inclusion criteria. Clinical and radiographic information about patient and implants was collected. Univariate and multivariate Cox proportional hazards frailty regression models were performed to identify risk factors for early and late implant failure.

Results: The cumulative implant survival rate was 95.62% (95% CI 93.90%-97.68%), with 16 early implant failures and 25 late implant failures. The Cox analysis indicated that ≤3 mm residual bone height (RBH) was associated with a higher early failure rate. For late implant failure, smoking habit, ≤3 mm RBH, and certain implant brand were independent risk factors. Narrow sinus ostium, long infundibulum, and flat thickening of Schneiderian membrane might be non-independent risk factors for late implant failure. No significance was found in other variables, including age, periodontitis history, implant characteristics (position, diameter, length, protrusion length, marginal bone loss), surgeon experience, healing time, opposing dentition, and prosthesis.

Conclusions: One-stage LSFE is a predictable treatment for patients with atrophic maxilla. ≤3 mm RBH increased the risk of early implant failure, while smoking habit, ≤3 mm RBH, and certain implant brand were independent risk factors for late implant failure.

Background: The cortical shell technique is frequently associated with technical drawbacks, such as the lack of anatomical guidance during shell harvest and graft. This study aims to assess the horizontal bone gain and accuracy of a digitalized protocol that incorporates two interlocking patient-specific stackable guides (PSSGs) to control the shell harvest, positioning, and fixation.

Patients and methods: Twenty patients with deficient anterior mandibles were randomly allocated; 10 patients received freehand symphyseal shell harvest and fixation (the control group), whereas the other 10 received fully guided harvest and graft (study group) using (PSSGs), the first aided an accurate shell harvest, whereas the second conveyed shell fixation. The interposition gap among both groups was loaded with an equal mix of xenogeneic and autogenous particulates. The mean radiographic bone gain among both groups was calibrated 6 months postoperatively, and the accuracy of the digital plan was assessed by superimposing and comparing the virtually planned horizontal bone dimensions with the immediate postoperative actual bone dimensions.

Results: The mean 6-month postoperative horizontal bone gain value of the study group was recorded as (4.97 ± 0.73) mm versus (4.45 ± 0.61) mm for the control group, with a statistically insignificant mean gain difference of (0.52) mm, (p = 0.101). The mean virtual preplanned horizontal bone gain was recorded (5.4 ± 0.6) versus (5.4 ± 0.6) for the immediate postoperative actual bone gain, which was also statistically insignificant (p = 0.9).

Conclusion: The (PSSGs) provided a precise method for graft harvest, position, and fixation, resulting in satisfactory alveolar ridge dimensions with intimate accuracy.

Objectives: To investigate whether a labially inclined implant axis compromises the clinical outcomes of immediate implant placement and provisionalization (IIPP) in the anterior maxilla.

Materials and methods: Patients with unsalvageable central or lateral maxillary incisors were enrolled. IIPP with simultaneous connective tissue graft (CTG) was performed in all participants. In the control group, the alveolar ridge had a long axis aligned with the tooth, which ensured that the immediate implant was aimed at the incisor edge or the cingulum of future restoration. The test group had a large angle between the axes of the ridge and tooth. To avoid bone fenestration, the implants were placed labially inclined and emerged from the labial side of future restoration. Intra-oral scanning and cone-beam computed tomography were performed to record soft and hard tissue profiles at baseline and 1 year later. Soft tissue stability, bone remodeling, and pink esthetic score (PES) were evaluated and compared between two groups.

Results: Thirty-nine participants (19 tests and 20 controls) completed the study. At 1-year post-surgery, the mid-facial gingival margin migrations were 0.85 ± 0.37 mm (test) and 0.81 ± 0.33 mm (control), without significant differences. No differences were identified in buccal profile alteration, linear ridge reduction, buccal bone thickness, or PES scores. The test group demonstrated thinner buccal soft tissue at the crestal level than the control group.

Conclusions: When large tooth-ridge angulation presented, labially inclined implant, avoiding buccal ridge fenestration in IIPP with CTG, did not compromise the clinical outcome in short term.

Statement of problem: Osseointegration is now primarily established, but soft tissue integration is still susceptible to failure and problematic on implant surfaces. So, implant dentistry is increasingly focusing on improving peri-implant soft tissue integration.

Purpose: The present study aimed to evaluate the blood fibrin clot formation and adhesion on the abutment after cleaning and decontamination and determine the suitable abutment surface associated with fibrin clot attachment.

Materials and methods: Forty-two abutments (14 per group) were used in the present study: a brand-new (BN), contaminated with biofilm (CO) and decontaminated with an enzymatic cleaner and autoclave sterilization (DEC). For a fibrin clot, 9 mL of whole human blood and abutments was centrifuged at 2700 rpm for 12 min. Clots were divided into two parts for histomorphometry and scanning electron microscopy (SEM) analysis. Twelve abutments disconnected from the clot and two not treated with blood were observed under SEM.

Results: Residual debris and biofilm were observed on the abutment surface in the CO group but not in other groups. Healthy and organized fibrin clots formed on all abutments. The fibrin extension areas are distributed uniformly in BN and DEC groups but irregularly in CO. The surface percentage of the fibrin clot extensions was 41.76% ± 6.73, 26.99% ± 6.40, and 37.83% ± 9.72 for the BN, CON, and DEC groups, respectively. The blood clot-attached areas in the CO group were statistically lower than the other groups. No difference was observed between the BN and DEC groups.

Conclusions: This study confirmed that surface contamination could influence blood clot attachment on the abutment surfaces. Cleaning and sterilization can have a favorable effect on soft tissue healing on abutment surfaces.

Background: The collaboration between otolaryngologists and dental providers is crucial for the planning and execution of maxillary sinus elevation (MSE) procedures, which are integral to successful dental implant placements.

Purpose: This article examines the essential role of otolaryngological assessments in identifying potential sinonasal risks that could impact the outcomes of MSE.

Materials and methods: A comprehensive narrative review of existing literature was conducted.

Discussion: The review underscores the importance of thorough preoperative evaluations, including patient history, computed tomography (CT) or cone-beam CT (CBCT) scans, and nasal endoscopy, to mitigate sinonasal health risks. It details various clinical scenarios and patient assessments, emphasizing a systematic approach to diagnosing and managing sinonasal conditions proactively. The discussion reveals that while some sinus conditions may not significantly affect MSE success, conditions impacting mucociliary clearance and sinus drainage are critical risk factors requiring otolaryngological intervention. Additionally, the article introduces a grading system to assist clinicians in identifying patients who would benefit from otolaryngological evaluations prior to MSE.

Conclusion: This review highlights the value of interdisciplinary collaboration and standardized protocols in enhancing the predictability and safety of MSE procedures, ultimately improving patient outcomes.