The International journal of oral & maxillofacial implants最新文献

Purpose: This study evaluated the accuracy of intraoral scanning at varying implant depths and resulting scan body exposures in maxillary anterior immediate implant placement.

Materials & methods: Three identical custom-made epoxy resin models were fabricated with extraction sockets present in the positions of teeth #6 and #11. Dental implants were placed at six different depths apical to the facial mucosal zenith (2.0, 3.0, 4.0, 5.0, 6.0, 7.0 mm), corresponding to of six different amounts of scan body exposure incisal to the facial mucosal zenith (8.9, 7.9, 6.9, 5.9, 4.9, 3.9 mm). Two hundred and forty intraoral scans (TRIOS 4, 3 Shape) were obtained by two independent examiners (twenty times per sites). The generated stereolithography files (STL files) were superimposed onto reference desktop scan files (D710, 3Shape) and analyzed using Geomagic Control X software with best-fit function. Accuracy (trueness and precision) of implant position were evaluated and reported as linear and angular deviations. The null hypothesis is that scanning accuracy would not differ significantly between the tested implant depths.

Results: Accuracy was relatively consistent with high trueness (˂30 µm) across the tested implant depths and resulting scan body exposures. Slightly higher variability was present in angular deviation at intermediate depths (notably 3.0 mm, with 0.053 ±0.026 degrees deviation). Therefore, the null hypothesis was accepted.

Conclusions: Within the limitation of this in vitro study, in maxillary anterior immediate implant placement, the scanning showed consistent high accuracy (<30 μm) across the tested depth levels. Also, the angular deviations were consistently low (<0.1 degrees). A digital workflow using an intraoral scanner and scan body should be clinically applicable for immediate implant placement and provisionalization scenarios within a range of scan body exposures incisal to the mucosa.

Purpose: After tooth loss, alveolar bone resorption is irreversible and often results in insufficient bone volume to consider implant placement. In recent years, Guided Bone Regeneration (GBR) with 3D-printed individualized titanium meshes has been increasingly employed in oral surgery, either as an alternative to or in combination with resorbable membranes, to achieve predictable bone regeneration prior to implant placement. Various mesh designs, mostly macro-porous and micro-porous structures, along with different surgical techniques, have been proposed. Although the approach has demonstrated consistent clinical reliability, complications such as mesh exposure and/or limited bone gain still occur. This study aims to evaluate the reliability of a GBR technique based on the use of micro-perforated grade-2 titanium meshes held by two vestibular screws and pure autologous bone, both in terms of clinical outcomes and bone gain.

Materials and methods: A retrospective study including sixteen patients implanted with this GBR technique in the same dental center was conducted. The meshes were digitally designed and manufactured using Direct Metal Laser Sintering in grade-2 titanium. All patients underwent a two-step bone regeneration procedure, including a first surgery for mesh placement, followed by a healing period of at least four months before the implant placement, with a secondary slight GBR being done. For each implanted titanium mesh, both the planned and the real bone augmentations were measured by three different operators using pre and post-surgical CBCT and planification data. A statistical linear mixed model was applied to the data (102 measurements) to assess any significant difference between the planned augmentation and the real clinical augmentation.

Results: All meshes were successfully implanted with no complications or exposition. After 122 to 160 days, all patients showed enough bone volume to ensure safe implant placement. No significant difference was observed between the planned bone augmentation and the clinical outcomes, indicating that the targeted augmentation was successfully achieved.

Conclusions: These results suggest a high level of short-term clinical reliability and predictability of the guided bone regeneration using 3D-printed individualized micro-perforated grade-2 titanium meshes in combination with pure autologous bone.

Purpose: To evaluate the mechanical behavior of two types of dental implants (both 2.9 mm in diameter) using physical and virtual mechanical testing methodologies.

Materials and methods: Two different extra-narrow Morse taper implant systems were evaluated: (1) Facility implants (2.9-mm diameter, 5-degree angulation of the internal conical portion) and (2) GM Narrow implants (2.9-mm diameter, 16-degree angulation of the internal conical portion). Both groups were evaluated on the results of the following methodologies: fractographic analyses and strength to failure, strain gauge, and thermomechanical cycling tests.

Results: Statistical analysis revealed a significant distinction (P < .001) between groups: The mechanical fracture efficiency of the narrow group was 25% greater than the Facility group. The examination using a scanning electron microscope revealed that all implants experienced fractures, with a tendency for these fractures to occur in areas with a lack of continuity at the implant-abutment interface. There was no difference between groups considering the strain around the cervical region of all implants tested (P = .987). The survival rate of crowns and prosthetic connections was 100%. There was no crown loosening, prosthetic component detachment, or fracture.

Conclusions: The proposed modifications for the new implant and abutment system had a positive impact on the mechanical behavior of the implant, with a 25% increase in fracture resistance and better stress distribution. Clinically, the GM Narrow system has become more resistant, but both systems can securely be used in restricted areas with low masticatory effort, such as for lateral incisors and mandibular incisors.

Purpose: To determine the relationship between primary stability (PS) and secondary stability (SS) and various implant characteristics.

Materials and methods: This retrospective cohort study included a total of 169 patients who received 445 dental implants. A case history was created for each participant. Data collection included each patient's age; implant design, length, and diameter; bone type; and other surgical factors. Implant stability quotient (ISQ) values were measured at baseline (T0 [for PS]) and after the appropriate osseointegration period (T1 [for SS]). To calculate the ISQ values at T0 and T1-and to compare their differences in the variables age, design, length, and diameter-a multivariate analysis of variance (ANOVA) test was performed to determine which variables acted as confounding factors and to adjust the ISQ values to these variables.

Results: The main variables (age, design, length, and diameter) were adjusted to their confounding factors. Regarding PS (T0) and SS (T1), statistically significant differences (P < .05) were only found for implant diameter; moreover, the larger the diameter, the greater the implant stability. For all other main variables, no statistically significant differences were found for PS and SS.

Conclusions: Within the limitations of this study, it can be concluded that implant diameter is the only variable that significantly affects the PS and SS of the implant.

Purpose: To develop insulin-like growth factor-1 (IGF-1)-loaded poly lactic-co-glycolic acid (PLGA) nanoparticles (NPs) with altered surface charges (cationic, anionic, and neutral) and evaluate their dual antimicrobial and osteogenic potential in vitro.

Materials and methods: IGF-1-loaded NPs were synthesized via solvent evaporation; characterized for size, charge, encapsulation efficiency, and release kinetics; and then were tested against peri-implant pathogens (Tannerella forsythia, Fusobacterium nucleatum, Prevotella intermedia, Porphyromonas gingivalis, Streptococcus mutans, and Staphylococcus aureus). The osteogenic potential was assessed using osteoblast-like (MG-63) and osteoclast precursor (U937) cell lines via proliferative (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), alkaline phosphatase (ALP), and tartrate-resistant acid phosphatase (TRAP) assays. Statistical analyses were performed using regression and one-way analysis of variance (ANOVA) (P < .05).

Results: The NPs displayed spherical morphology with sizes ranging from 74.7 ± 2.2 nm to 151.7 ± 1.3 nm, confirmed with scanning electron microscopy, and zeta potentials from -15.6 ± 0.24 mV to +29.8 ± 1.4 mV. Encapsulation efficiencies were 66% to 75%, with sustained IGF-1 release of 64% to 67% over 21 days. Cationic NPs showed the strongest antimicrobial efficacy (minimum inhibitory concentration [MIC]: 378 to 756 ng/mL for secondary pathogens and 1,512 ng/mL for primary pathogens), while neutral NPs demonstrated superior osteogenic activity, significantly enhancing MG-63 proliferation and ALP activity. Anionic NPs provided a broader antimicrobial spectrum but required higher concentrations for bactericidal effects.

Conclusions: Surface-modified IGF-1-loaded PLGA NPs achieved a dual therapeutic effect, combining potent antibacterial activity and enhanced osteogenesis. These findings support their potential as a nonantibiotic strategy for peri-implantitis management and bone regeneration. Modulating the charge potential of implant graft materials enhances both antibacterial activity against peri-implant pathogens and osteogenic efficiency, promoting bone regeneration and improving peri-implant health.

Purpose: To perform a comprehensive bibliometric analysis of the available literature on osseodensification (OD) as a surgical method for implant site preparation to identify research trends and areas that require further investigation.

Materials and methods: A refined search was conducted in the Web of Science Core Collection (WoS-CC) using keywords related to OD. No language restrictions were applied. Articles published between February 2016 and November 2023 were analyzed using VOSviewer software for bibliographic characteristics, including study design, level of evidence (LoE), country of the corresponding author, funding, authorship, journal impact factor (IF), and author keywords.

Results: A total of 63 publications were included in the study. The analyzed publications gathered 673 citations, with a mean of 10.68 ± 17.37 citations. No significant difference in the citation count was observed between original articles and reviews (P = .884). A total of 265 authors from 29 countries contributed to the publications, with an international collaboration of 82%. The USA was the most prominent country, with 23 publications. Of the publications, 52% were preclinical with LoE 0, followed by 13% with LoE IV, and 11% with LoE II. Primary research topics included implant stability, osseointegration, and bone density.

Conclusions: OD shows promise as an alternative technique for implant site preparation, enhancing primary stability in low-density bone regions. While preclinical studies indicate favorable outcomes, further clinical research is necessary to validate these findings.

Purpose: To investigate the influence of a discrepancy in crestal bone height between two neighboring implants and how it affects MBL over time.

Materials and methods: Medical and dental records and periapical radiographs of individuals with at least two adjacent implants were retrieved and analyzed. Records were divided into two groups according to the prosthetic part: (1) nonsplinted (NS) and (2) splinted (S) groups. Furthermore, groups were categorized by crestal bone height level (CBHL) differences between the two adjacent implant platforms: (1) ≤ 0.75 mm, (2) 0.76 to 1.25 mm, (3) 1.26 to 1.75 mm, and (4) > 1.75 mm. Radiographic measurements were performed at three time points: time of abutment placement (T0), 1 to 3 years of follow-up (T1), and at the last visit (T2). Multilevel linear regression models using generalized estimating equations were used, with a significance level of 5% (α = .05).

Results: A total of 56 patient records with 120 implants (84 NS [70%] and 36 S [30%]) were included. In the NS group, the mean mesial bone loss (T0 measurements subtracted from T2 measurements) of the most posteriorly positioned implant was 2.9, 3.1, 3.4, and 3.9 mm, respectively, across height intervals; the mean distal bone loss of the most anteriorly positioned implant was 3.1, 3.3, 3.4, and 3.9 mm, respectively, across height intervals. In the S group, mean mesial bone loss was 1.1, 2.1, 2.7, and 0.9 mm, respectively, across different height intervals, while the mean distal bone loss was 1.6, 2.1, 1.6, and 1.3 mm, respectively. Results from linear regression showed that NS implants exhibited more marginal bone loss (MBL) progression as the vertical difference between adjacent implants increased (P < .001). The S group showed 1.73 mm less bone loss than the NS group at the mesial side and 1.79 mm more bone loss on the distal side (P < .001) when both had the same CBHL difference (P < .001).

Conclusions: This study suggests that MBL progression depends on the difference in crestal height and is aggravated in NS implants.

Purpose: To compare the peri-implant bone surrounding a new abutment-free tissue-level implant design with classic tissue-level implants restored with titanium-base (Ti-base) abutments.

Materials and methods: A retrospective cohort study was conducted between 2018 and 2022 in patients requiring dental implants. A total of 53 patients received either a novel abutment-free tissue-level implant (n1 = 50 sites) or a conventional tissue-level implant (n2 = 50 sites). Patients were monitored for 1 year after prosthetic loading, with the primary endpoint being any change in hard tissue around the implant. Bone resorption was evaluated using CBCT. Statistical analyses included Fisher exact test for categorical variables and Student t test for continuous variables. Longitudinal outcomes were assessed using linear mixed models to account for within-patient correlations over time. The models incorporated treatment group, time, and their interaction, with statistical significance evaluated using Wald tests. Non-inferiority was assessed with one-sided P values < .025, while two-sided P values < .05 indicated statistical significance.

Results: No significant differences in patient demographics or complications were found between abutment-free and conventional implants. However, abutment-free implants exhibited less buccal bone loss than traditional implants. The abutment-free implant group had significantly lower palatal/lingual bone loss (P = .041) and alveolar ridge width reduction (P = .040) after 1 year of follow-up.

Conclusions: The results of this study suggest that abutment-free dental implants offer advantages in reducing buccal bone loss compared to conventional implants, potentially due to their ability to mitigate risks to peri-implant tissues. Further research is warranted to evaluate their long-term efficacy and safety.

Purpose: To evaluate the primary stability of short implants vs conventional implants in vitro.

Materials and methods: Two groups of implants, short implants (6.0 × 7 mm) and conventional implants (3.75 × 10 mm), with a reverse concave neck and neck microthreads (ULT, Ditron Dental) were studied. A total of 80 implants (40 short implants and 40 conventional implants) were placed by the same calibrated clinician (G.R.) at 800 rpm. Each implant was placed in hard (type 2) and soft (type 4) bone. Implant primary stability was recorded using insertion torque (IT), resonance frequency analysis (RFA), and Periotest values (PTVs). Statistical comparison with one-way analysis of variance (ANOVA) were completed to compare differences between groups.

Results: The comparison of IT and RFA values and PTVs of the two implant groups showed statistical significance (P < .0001) favoring the short implants in both the soft and hard bone qualities.

Conclusions: Within the limitations of this study, short implants with a wide diameter seem to have a higher level of implant stability compared to narrow implants with a conventional length.