International Journal of Implant Dentistry最新文献

Purpose: We assessed the efficiency of low-dose recombinant human bone morphogenetic protein-2 (rhBMP-2) incorporated biomimetic calcium phosphate on β-tricalcium phosphate (β-TCP) (rhBMP-2/BioCaP/β-TCP) on bone formation in a model of socket preservation using cone beam computed tomography (CBCT) scanning and histological examination.

Methods: Forty patients undergoing minimally invasive single-root tooth extraction for dental implantation were randomized to three groups according to the material used for socket preservation: filling with rhBMP-2/BioCaP/β-TCP, β-TCP, or natural healing (kept unfilled) (controls). The alveolar sockets (including the control group) were covered by two-layer collagen membranes and sutured. Two CBCT scans were taken, one immediately after socket preservation procedure (baseline) and another 6 weeks later. Gray values (GVs) obtained from CBCT were recorded. During insertion of the dental implant, biopsies were taken and analyzed histologically for new bone formation, residual material, and unmineralized bone tissue at the core of the biopsy.

Results: The mean (± standard deviation) changes of GVs of the CBCT scans at the central area of filled materials were as follows: 373.19 ± 157.16 in the rhBMP-2/BioCaP/β-TCP group, 112.26 ± 197.25 in the β-TCP group, and -257 ± 273.51 in the control group. The decrease of GVs in the rhBMP-2/BioCaP/β-TCP group as compared with the β-TCP group was statistically significant (P < 0.001). Differences in new bone formation (P = 0.006) were also found: 21,18% ± 7.62% in the rhBMP-2/BioCaP/β-TCP group, 13.44% ± 6.03% in the β-TCP group, and 9.49% ± 0.08% in controls. The residual material was10.04% ± 4.57% in the rhBMP-2/BioCaP/β-TCP group vs. 20.60% ± 9.54%) in the β-TCP group (P < 0.001). Differences in unmineralized bone tissue (P < 0.001) were also found (68.78% ± 7.67%, 65.96% ± 12.64%, and 90.38% ± 7.5% in the rhBMP-2/BioCaP/β-TC, β-TCP, and control groups, respectively).

Conclusions: This study shows that rhBMP-2/BioCaP/β-TCP is a promising bone substitute with fast degradation and potent pro-osteogenic capacity that can be useful for socket preservation in implant dentistry.

Trial registration: ChiCTR, ChiCTR2000035263. Registered 5 August 2020, https://www.chictr.org.cn/ChiCTR2000035263 .

Purpose: To evaluate collagen scaffolds (CS) in terms of their in vitro resorption behavior, surface structure, swelling behavior, and mechanical properties in physiologically simulated environments, compared with porcine native connective tissue.

Materials and methods: Three test materials-one porcine collagen matrix (p-CM), two acellular dermal matrices (porcine = p-ADM, allogenic = a-ADM)-and porcine native connective tissue (p-CTG) as a control material were examined for resorption in four solutions using a high-precision scale. The solutions were artificial saliva (AS) and simulated body fluid (SBF), both with and without collagenase (0.5 U/ml at 37 °C). In addition, the surface structures of CS were analyzed using a scanning electron microscope (SEM) before and after exposure to AS or SBF. The swelling behavior of CS was evaluated by measuring volume change and liquid absorption capacity in phosphate-buffered saline (PBS). Finally, the mechanical properties of CS and p-CTG were investigated using cyclic compression testing in PBS.

Results: Solutions containing collagenase demonstrated high resorption rates with significant differences (p < 0.04) between the tested materials after 4 h, 8 h and 24 h, ranging from 54.1 to 100% after 24 h. SEM images revealed cross-linked collagen structures in all untreated specimens. Unlike a-ADM, the scaffolds of p-CM and p-ADM displayed a flake-like structure. The swelling ratio and fluid absorption capacity per area ranged from 13.4 to 25.5% among the test materials and showed following pattern: p-CM > a-ADM > p-ADM. P-CM exhibited higher elastic properties than p-ADM, whereas a-ADM, like p-CTG, were barely compressible and lost structural integrity under increasing pressure.

Conclusions and clinical implications: Collagen scaffolds vary significantly in their physical properties, such as resorption and swelling behavior and elastic properties, depending on their microstructure and composition. When clinically applied, these differences should be taken into consideration to achieve the desired outcomes.

Objectives: The main purpose of this study was to evaluate whether large granular bovine bone can be as effective as small granular bovine bone in maxillary sinus floor elevation.

Methods: A comprehensive online search of eligible articles was conducted using PubMed, EMBASE, Cochrane Library, Scopus, and Web of Science, and a systematic review and meta-analysis was performed from establishment to February, 2023. The outcome indicators were the percentage of connective tissue, the percentage of newly formed bone and the percentage of residual xenograft respectively. The meta-analysis was conducted by using the Stata 15.1 (Stata Conpernarn, USA) and Review Manager software5.4.1.

Results: After careful screening and review, a total of 4 studies were included for systematic review and meta-analysis. The data were extracted to compare the histological performance of bovine bones with different particle sizes after maxillary sinus elevation. No significant differences were found in the percentage of connective tissue, the percentage of newly formed bone, and the percentage of residual xenograft.

Conclusion: In this study, a systematically review of the previous literature showed that similar histological results were obtained for both large-particle bovine bone and small-particle bovine bone. Therefore, the large granular bovine bone and the small granular bovine bone were equally effective in maxillary sinus elevation. It is difficult to make conclusion from limited evidence from four studies. More clinical evidence was needed.

Purpose: This systematic review aimed to evaluate the incidence of microleakage events (IME) and to identify the potential factors influencing the sealing ability of the implant-abutment interface (IAI) under in vitro investigation.

Material and methods: An electronic search of MEDLINE (PubMed), EMBASE, and Web of Science databases, combined with a manual literature search was conducted up to September 2022. In vitro studies that reported the degree of microleakage at IAI under dynamic loading conditions were included. A meta-analysis was performed to calculate the mean values of the incidence of microleakage events. Subgroup analysis and meta-regression were conducted to further investigate the effect of different variables.

Results: 675 studies were identified following the search process and 17 in vitro studies were selected according to the eligibility criteria. The weighted mean incidence of microleakage events was 47% (95% confidence interval: [0.33, 0.60]), indicating that contamination was observed in nearly half of the samples. Concerning possible factors that may influence microleakage (e.g., loading condition, assessment method, implant-abutment connection design, types of abutment material, the use of sealing agents), loading condition (p = 0.016) was the only variable that significantly influenced IME in the meta-regression analysis.

Conclusions: The results demonstrated that dynamic loading significantly increases the potential of bacterial penetration at the implant-abutment junction. The results should be interpreted carefully due to the data heterogeneity and further well-conducted in vitro studies with homogeneous samples are needed to standardize the methodologies.

Purpose: Dental implant abutments are defined as medical devices by their intended use. Surfaces of custom-made CAD/CAM two-piece abutments may become contaminated during the manufacturing process in the dental lab. Inadequate reprocessing prior to patient care may contribute to implant-associated complications. Risk-adapted hygiene management is required to meet the requirements for medical devices.

Methods: A total of 49 CAD/CAM-manufactured zirconia copings were bonded to prefabricated titanium bases. One group was bonded, polished, and cleaned separately in dental laboratories throughout Germany (LA). Another group was left untreated (NC). Five groups received the following hygiene regimen: three-stage ultrasonic cleaning (CP and FP), steam (SC), argon-oxygen plasma (PL), and simple ultrasonic cleaning (UD). Contaminants were detected using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) and segmented and quantified using interactive machine learning (ML) and thresholding (SW). The data were statistically analysed using non-parametric tests (Kruskal-Wallis test, Dunn's test).

Results: Significant differences in contamination levels with the different cleaning procedures were found (p ≤ 0.01). The FP-NC/LA groups showed the most significant difference in contamination levels for both measurement methods (ML, SW), followed by CP-LA/NC and UD-LA/NC for SW and CP-LA/NC and PL-LA/NC for ML (p ≤ 0.05). EDS revealed organic contamination in all specimens; traces of aluminum, silicon, and calcium were detected.

Conclusions: Chemothermal cleaning methods based on ultrasound and argon-oxygen plasma effectively removed process-related contamination from zirconia surfaces. Machine learning is a promising assessment tool for quantifying and monitoring external contamination on zirconia abutments.

Purpose: Narrow-diameter implants facilitate single-tooth restoration when interdental or inter-implant spaces and bone volume are inadequate for using standard diameter implants. This study reports the short-term data on the clinical safety and performance of a bone-level-tapered two-piece implant with a 2.9 mm diameter in the clinical practice setting. This study was retrospectively registered on March 1st, 2016 (NCT02699866).

Methods: Implants were placed in partially healed extraction sockets of the central and lateral incisors in the mandible and lateral incisors in the maxilla for single-tooth replacement. The primary outcome was to assess implant survival at 12 months after placement. Secondary outcomes included implant success, pink esthetic score, marginal bone-level changes, and safety.

Results: Twenty four males and 17 females with a mean age of 44.5 (± 18.3 standard deviation) received the implant. Three out of 41 implants were lost yielding a survival rate of 92.7% (95%-CI: 79.0%; 97.6%) at 1 year. One patient reported an ongoing foreign body sensation, pain, and/or dysesthesia at month 12. The average pink esthetic score at 6 months was 11.2 (95%-CI: 10.5; 11.9). The bone level was stable with a mean bone-level change of-0.3 mm (± 0.42 mm standard deviation) at 1 year after implantation. No serious adverse events or adverse device events were reported.

Conclusions: The use of a 2.9 mm diameter bone-level-tapered implant is a safe and reliable treatment option for narrow tooth gaps at the indicated locations. Overall performance and good survival rates support their use in cases, where wider implants are unsuitable.

Purpose: Sinus lift operations are a tried and tested means of providing adequate implant prosthetics to patients with compromised jawbones. Knowledge of the arterial supply of the maxillary sinus region is essential for surgical treatment in this area. The aim of the present comparative study was to determine whether alveolar antral artery (AAA) canal can be diagnosed both in corresponding panoramic radiography (PR) and cone-beam computed tomography (CBCT).

Methods: A total of 335 patients with 635 sites and corresponding maxillary sinus in both PR and CBCT were selected and examined for AAA canal visibility.

Results: The visibility of the AAA canal was significantly higher in CBCT than in PR. A total of 154 (46.0%) AAA canals could be identified in the maxillary sinus on the right. However, only four (1.2%) of these were also visible in PR. The detected values of the AAA canals in the maxillary sinus on the left in the PR and CBCT images were similar to those of the right. While 164 AAA canals (49%) were observed in CBCT images, only 1 (0.3%) was identifiable in PR.

Conclusions: The results show that CBCT can be recommended for visualising the AAA canal when surgically planning sinus augmentation procedures.

Background: Appropriate load distribution among the supporting elements is essential for the long-term success of implant-assisted removable partial dentures; however, there is little information available on load distribution.

Purpose: This study aimed to evaluate the effect of implant location on load distribution in implant-assisted removable partial dentures by reviewing in vitro models and finite-element analysis studies.

Materials and methods: English-language studies which examined the load distribution of implant-assisted removable partial dentures and were published between January 2001 and October 2022 were extracted from PubMed, ScienceDirect, and Scopus online databases, and manual searching. Two reviewers selected the articles based on the predetermined inclusion and exclusion criteria, followed by data extraction and analysis.

Results: Forty-seven studies were selected after evaluating the titles and abstracts of 264 articles; two were identified manually. After screening the text, 12 studies were included: six in vitro model experiments and six finite-element analysis studies. All included studies used a mandibular free-end missing model (Kennedy Class I or II). The influence of implant location on load distribution to the abutment tooth, implant, and mucosa under the denture base was summarized in three cases: implant at the premolar, first molar, and second molar region. Due to differences in the measurement method of load distribution and loading condition to the denture, the results differed among the studies.

Conclusions: The implant location in implant-assisted removable partial dentures can affect load distribution to the supporting elements, such as the abutment tooth, implant, and mucosa under the denture base.

Purpose: Increasing scientific evidence support extending the application of short dental implants to non-atrophic dental arches. The purpose of this study has been the evaluation of extra-short implants (≤ 6.5 mm in length) that were placed in atrophic and non-atrophic anatomical sites to support the same prosthesis.

Methods: For that, a retrospective study was conducted by including complete dentures that were solely supported by extra-short implants in the maxilla and/or the mandible. Clinical data about patients, implants, anatomy, and prosthesis were obtained. Statistical analysis was performed to assess implant- and prosthesis-survival, changes in the marginal bone level and prosthetic complications.

Results: A total of 87 implants in 15 screw-retained complete dentures were assessed. None of the prostheses nor the extra-short implant failed during the follow-up of 27.2 ± 15.4 months. The changes in the mesial and distal marginal bone level were + 0.15 ± 0.51 mm and + 0.11 ± 0.50 mm, respectively. Comparing the implants according to the availability of sufficient bone to place longer implants, indicated the absence of significant differences in the changes of the mesial marginal bone level. However, the changes in the distal marginal bone level showed a statistically significant difference in favor of implants that were placed in non-atrophic sites. Two events of screw loosening were reported that were resolved by retightening the screws.

Conclusions: Implant- and prosthesis-related outcomes support the use of extra-short implants in atrophic and non-atrophic site to support complete prosthesis.

Objectives: The aim of the ITI Consensus Workshop on zygomatic implants was to provide Consensus Statements and Clinical Recommendations for the use of zygomatic implants.

Materials and methods: Three systematic reviews and one narrative review were written to address focused questions on (1) the indications for the use of zygomatic implants; (2) the survival rates and complications associated with surgery in zygomatic implant placement; (3) long-term survival rates of zygomatic implants and (4) the biomechanical principles involved when zygoma implants are placed under functional loads. Based on the reviews, three working groups then developed Consensus Statements and Clinical Recommendations. These were discussed in a plenary and finalized in Delphi rounds.

Results: A total of 21 Consensus Statements were developed from the systematic reviews. Additionally, the group developed 17 Clinical Recommendations based on the Consensus Statements and the combined expertise of the participants.

Conclusions: Zygomatic implants are mainly indicated in cases with maxillary bone atrophy or deficiency. Long-term mean zygomatic implant survival was 96.2% [95% CI 93.8; 97.7] over a mean follow-up of 75.4 months (6.3 years) with a follow-up range of 36-141.6 months (3-11.8 years). Immediate loading showed a statistically significant increase in survival over delayed loading. Sinusitis presented with a total prevalence of 14.2% [95% CI 8.8; 22.0] over a mean 65.4 months follow-up, representing the most common complication which may lead to zygomatic implant loss. The international experts suggested clinical recommendations regarding planning, surgery, restoration, outcomes, and the patient's perspective.