Clinical implant dentistry and related research最新文献

Introduction: Implantoplasty can be performed on implants diagnosed with peri-implantitis to facilitate implant decontamination and improve access for oral home care. However, its effect on the mechanical strength of the implant is still uncertain. This study aimed to evaluate the effect of implantoplasty on the fracture resistance of dental implants with various degrees of bone loss, as well as its surface changes.

Methods: Eighty 4.2 × 13 mm conical connection dental implants were allocated evenly into four groups based on the bone defect morphology: circumferential or semi-circumferential, and 3 or 5 mm vertical height. Half of the implants underwent implantoplasty with tungsten carbide finishing burs. Weight, volume, and surface roughness of the implants were recorded prior to and after instrumentation. All implants were subjected to static loading to failure or fracture and the implant surfaces were then analyzed using optical microscopy. Finite element analysis was carried out to assess the stress pattern on dental implants after implantoplasty.

Results: Implantoplasty significantly reduced the fracture resistance of implants with all defect morphologies, aside from those with 3 mm of circumferential bone loss. Implants with 5 mm of peri-implant bone loss also experienced significantly reduced fracture resistance compared to the 3 mm group. Significant decrease in fracture resistance was only observed between the circumferential and semi-circumferential groups with 5 mm of bone loss. Surface roughness was also significantly reduced following implantoplasty. The results from finite element analysis revealed a change in pattern of stress concentration in the implant after implantoplasty.

Conclusion: Implantoplasty negatively impacted the fracture resistance of standard diameter dental implants in most scenarios. The increase in exposed implant length resulted in a decrease in fracture resistance. This increase in fracture risk should be considered prior to implantoplasty, especially in implants with more advanced bone loss.

Introduction: This study aimed to analyze the factors affecting the occurrence of peri-implant medication-related osteonecrosis of the jaw (PI-MRONJ) in patients using anti-resorptive drugs (ARDs) on different implant position, inclinations, and types of prosthesis.

Methods: The data of 75 patients with bone necrosis that progressed around the implant between 2018 and 2022 were retrospectively examined to identify the factors influencing PI-MRONJ. Data, including patient demographics (age, sex, smoking status, concomitant disease, time of ARD therapy, dose of ARDs, and parafunctional habits) and implant-specific information (type of prosthesis, angle of insertion), were extracted from medical and dental records.

Results: Tilted implants with an angle ≥ 5.1° relative to the occlusal plane of the prosthesis had a stronger association with PI-MRONJ in comparison to non-tilted implants (inclination was < 5°). Additionally, the boundary of the area of osteonecrosis around the fixture was larger for the splinted implant-supported crowns than for the single implant supported crowns).

Conclusion: In patients taking anti-resorptive medications the inclination of the implant was associated with the occurrence of PI-MRONJ. Further studies are required to confirm the clinical findings.

Background: Full-arch immediate loading rehabilitations are now a widely used rehabilitation method that guarantees predictable medium- and long-term results. Numerous factors can influence its success and stability in the medium and long term. Among these the implant-abutment connection seems to play an important role, however there is still little information on which is the most suitable in this type of treatment.

Purpose: The aim of the present multicenter split-mouth controlled trial is to evaluate whether external hexagonal connections (EHC) and internal hexagonal connections (IHC) can influence success, bone resorption and peri-implant parameters in immediate-load full-arch rehabilitations.

Materials and methods: Twenty patients were rehabilitated with immediately loaded fixed full-arch rehabilitations. All the implants presented the same macro- and micro-topography but different implant-abutment connection. IHC were used in one randomly selected side of the jaw and EHC was used in the other side. Outcome measures were implant survival rate, peri-implant marginal bone loss (MBL), plaque index (PI), probing depth (PD), and bleeding on probing (BoP) evaluated at 3, 6, 12, 36, and 72-month post-loading. Technical and biological complications were recorded.

Results: In 20 patients, 43 EHC and 40 IHC implants were placed. Between 32 and 72 months of follow-up two patients withdrew (died) and no implants were lost. The cumulative survival rate (CSR) was 97.44% for EHC implants and 97.22% for IHC implants. The MBL presented a resorption of 2 mm in the EHC group and 1.9 mm in the IHC group. No statistically significant differences were found between the two groups for any of the parameters at any time. No biological or technical complications were detected between the 36th and 72nd month of follow-up.

Conclusions: After 72 months in function, both internal and external hexagon connections provided good clinical outcomes and were not associated with any significant difference in the clinical outcomes.

Objective: To evaluate the efficacy of 3D-printed scaffolds that were osteoinductively functionalized with a bone morphogenetic protein 2 (BMP-2)-incorporated biomimetic calcium phosphate particles (BMP-2-inc. BpNcCaP)/hyaluronic acid (HA) composite gel in vertical bone augmentation in beagle dogs.

Materials and methods: Four Beagle dogs were used in this study. Three months after the extraction of 1st, 2nd, 3rd, and 4th premolars at both sides of the lower jaws of Beagle dogs, one or two critical-size vertical bone defects (4 mm vertical bone defect without buccal and lingual bone) on each side were surgically created. The defects were randomly subjected to the following groups: (1) Control (without bone-defect-filling materials); (2) 3D scaffold; (3) BMP2-inc. BpNcCaP/HA-functionalized 3D scaffold. Six weeks post-surgery, samples were harvested and subjected to micro-CT and histomorphometric analyses.

Results: The struts of the BMP2-inc. BpNcCaP/HA-func. 3D scaffold were covered by a thick layer of cemented irregular particles with an average pore size at 327 ± 27 μm. The BpNcCaP/HA-func. 3D scaffold group bore significantly higher bone volume, bone volume fraction, trabecular number, trabecular thickness, bone mineral density, connectivity density, and bone volumes in three directions (mesiodistal, buccolingual, and apicocoronal) when compared with the groups of Control and 3D scaffold. Moreover, the BMP2-inc. BpNcCaP/HA-func. 3D scaffold group bore significantly lower trabecular separation and exhibited significantly higher bone-to-scaffold contact percentage and newly formed bone area percentage within pores in comparison with 3D scaffold.

Conclusions: BMP2-inc. BpNcCaP/HA-func. 3D scaffold dramatically enhanced vertical alveolar bone augmentation, which suggests a promising application potential of BMP2-inc. BpNcCaP/HA-func. 3D scaffold in dental clinic.

Background: Sinus floor elevation is one of the predictable techniques for augmentation of vertically deficient posterior maxillary alveolar ridges. Several biomaterials were reported to be successful for sinus augmentation, including xenografts and hydroxyapatite. The aim of this study was to compare the quality and quantity of generated bone using xenografts versus nanohydroxyapatite in sinus augmentation.

Methodology: Twenty-four patients/sinuses were randomly assigned into two groups; in the control group, patients underwent sinus floor elevation and augmentation using deproteinized bovine bone (DBB), whereas in the study group, the sinus was augmented using nanohydroxy-apatite bone (NHA). For each patient, the amount of bone height was assessed preoperatively, immediately postoperatively, and 6 months postoperatively. Furthermore, the quality of the newly formed bone was assessed via histological and histomorphometric analyses after 6 months postoperatively.

Results: Both biomaterials showed a good level of consolidation. In the study group, the mean bone height after 6 months was 11.72 ± 1.24 compared to 12.01 ± 1.16 mm in the control group which was not statistically significant (p > 0.05). The mean bone area percent of newly formed bone was 29.84% ± 6.7% for NHA group and 34.73 ± 7.9 for DBB group. Moreover, the mean percent of residual grafting material was 32.43% ± 11.53% for NHA group compared to 30.43% ± 8.27% for DBB group. Histologically, there was no significant difference between both groups regarding different parameters (p > 0.05).

Conclusion: The two-stage sinus floor augmentation using NHA and DBB revealed no statistically significant difference regarding both the quality and the quantity of the regenerated bone. Studies with larger samples and longer follow up are recommended.

Trial registration: ClinicalTrials.gov identifier: NCT03184857.

Aim: Technology improvement and a better understanding of sinus anatomy and wound healing in the past decade have allowed the development of minimally invasive surgical techniques. This systematic review focused on identifying and describing these techniques for vertical and lateral sinus augmentation (VSA and LSA).

Materials and methods: Electronic and hand search were conducted to screen the literature published from January 2003 to May 2024. The selected studies had to include detailed techniques for minimally invasive SA. Data extraction included the study types, sample size, technique/instrument details, and outcome measurements.

Results: A total of 36 articles (27 VSA, 8 LSA with an additional 1 article included both procedures) with 2732 sinus augmentation met the inclusion criteria. Minimally invasive VSA includes the use of modified rotary instruments with stopper, balloon, hydraulic pressure, digital planning, endoscope, and operating microscope. These techniques aim for conservative flap reflection, precise sinus window preparation, and/or controlled sinus membrane elevation. Most of the selected studies (n = 15) did not report the incidence of sinus membrane perforation.

Conclusion: Within the limitations of this review, minimally invasive VSA and LSA achieved sufficient sinus augmentation and implant success with the potential advantages of reduced surgical complications and morbidity. Comparative studies with defined outcomes are encouraged to further validate these useful minimally invasive techniques for SA.

Objectives: The objective of this study is to investigate the effect of collagen matrix with polydeoxyribonucleotide (PDRN) at two concentrations on keratinized tissue (KT) regeneration for buccally positioned implants in canines.

Methods: Four implants were placed in the edentulous mandible of five dogs simultaneously with KT removal. The implants were positioned buccally with respect to the ridge crest. After 2 months, KT augmentation was performed applying the following treatment modalities:(1) free gingival graft (FGG), (2) xenogeneic collagen matrix (XCM), (3) XCM loaded with 2 mg/mL PDRN (PDRN2), and (4) XCM loaded with 4 mg/mL PDRN (PDRN4). All animals were sacrificed 3 months later. Outcomes included clinical (KT height) and histomorphometric measurements (KT height/length, level of the mucosa, mucosal thickness, supracrestal soft tissue height).

Results: Clinical and histomorphometric KT formation at 3 months was greatest in groups with FGG (4.70 ± 1.00/3.94 ± 0.93 mm) and PDRN2 (4.85 ± 1.43/3.95 ± 0.87 mm). Group PDRN2 (1.87 ± 1.50 mm) showed a higher marginal mucosal level with respect to the implant platform compared to other groups (range: 0.57 ± 0.97-0.69 ± 1.14 mm). All groups presented a soft tissue thickness of < 2 mm on the buccal aspect of the implants.

Conclusions: Based on the limitations of this pilot preclinical study, XCM with 2 mg/mL of PDRN demonstrated a potential for KT augmentation.

Objective: The study evaluates three biologically active substances with known bone-inductive potential on previously decontaminated titanium (Ti) discs.

Material and methods: Rough and smooth Ti surfaces were contaminated with a multispecies biofilm and cleaned with a chitosan brush. Discs were treated either with injectable-platelet-rich fibrin (i-PRF), advanced platelet-rich fibrin (A-PRF+), or enamel matrix derivatives (EMDs) before osteoblast seeding.

Results: Biocompatibility, adhesion, migration, and gene expression of runt-related transcription factor 2 (RUNX2), collagen Type I Alpha 2 (COL1a2), alkaline phosphatase (ALP), osteocalcin (OC), and osteonectin (ON) were performed. All the tested biologic agents similarly increased cell viability. Specifically, osteoblasts seeded over i-PRF and EMD-treated surfaces showed improvement in adhesion and migration and significantly increased ALP, OC, ON, RUNX-2, and COL1a2 mRNA levels up to 2.8 fold (p < 0.05) with no differences between Ti surfaces.

Conclusions: i-PRF and EMD possess beneficial bioactive properties that enhance tissue healing and promote regeneration on thoroughly sterilized surfaces. Biologically active materials may hold the potential to influence the process of implant re-osseointegration, which warrants more research since sterilization of the affected surfaces under clinical conditions is still not reliably possible and remains one of the greatest challenges.