The International journal of oral & maxillofacial implants最新文献

Purpose: To evaluate the clinical and radiographic results of simultaneous implant placement using transcrestal sinus floor elevation (TSFE) with and without enamel matrix derivative (EMD) application.

Materials and methods: Twenty-four patients were randomly assigned into two groups: The EMD+TSFE group (n = 13 patients, 20 implants) received TSFE with EMD application, and the TSFE group (n = 11 patients, 20 implants) received TSFE without EMD application. The patients were recalled at 3 (T3) and 12 (T12) months postsurgery. The residual bone height (RBH), implant protrusion length (IPL), peri-implant sinus bone level (SBL), endo-sinus bone gain (ESBG), and implant stability (ISQ) were measured. Multivariate regressions were performed for the groups.

Results: At T3, the ESBG was 3.72 ± 0.85 mm in the EMD+TSFE group and 3.10 ± 0.05 mm in the TSFE group, and there were statistically significant differences (P < .05). However, there were no statistically significant differences in ESBG at T12 between the groups (P > .05). ISQ values did not show a statistical difference between the groups at T1 and T3, but at T3 in the TSFE+EMD group, there was a statistical increase in the intragroup evaluation compared to the TSFE group.

Conclusions: The use of EMD in TSFE procedures is effective in new bone formation at the apical part of the implant during the early healing period, but in the long term, no significant difference was shown between cases in which EMD was or was not used in terms of new bone formation and primary and secondary stabilization.

Purpose: To evaluate the correspondence between output from a new artificial intelligence tool (AIT) and clinician evaluation regarding the immediate loading suitability of dental implants based on insertion torque curves recorded during implant placement in an in vitro test. The secondary aim was to analyze peak insertion torque (PIT) and variable torque work (VTW) values of the implants.

Materials and methods: The study was performed with four different densities of artificial bone blocks of solid rigid polyurethane without a cortical layer. Five types of implants with different macrogeometries were used. A total of 140 implants (7 implants of each type in the four polyurethane blocks) were inserted. Immediately after implant placement, the insertion torque curves were classified by the operator as suitable (S) or nonsuitable (NS) for immediate loading. The same curves were then analyzed by the new AIT, which classified them as belonging to the 'YES' or 'NO' class. For each implant, PIT and VTW values were also recorded.

Results: The correspondence between clinician and AIT evaluation was 99.3%, with only one false negative reported by the algorithm analysis. The AIT was found to have a sensitivity of 98.95%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 97.8%. Mean PIT of the whole sample was 34.19 ± 19.43 Ncm, while mean VTW was 2,266.89 ± 1,993.73 Ncm. Statistically significant differences were found between implant systems in the whole sample and according to density of the polyurethane block.

Conclusions: The AIT showed a high level of accuracy in the prediction of immediate loading suitability of dental implants based on the provided insertion torque curves. All the implants used in the in vitro test achieved good levels of primary stability, except when inserted in the least-dense polyurethane block. Clinical studies conducted with larger samples and more clinicians are necessary to confirm these results.

Purpose: To compare the effect of taper, length, angle, and number of vertical axial walls on the retentive strength of a cemented crown on a partially customized hybrid abutment in the esthetic zone.

Materials and methods: A total of 35 metal copings were used and divided into two groups. One group had 30 copings cemented to their corresponding 8-degree tapered abutment with lengths from 3 to 8 mm, increasing in 1-mm increments (5 copings per length). The other group had the remaining 5 copings and consisted of a standardized metal coping that matched a hexagonal abutment with 3-mm vertical axial walls and the sequential removal of 1, 2, and 3 contiguous vertical axial walls. Dislodgment tests were performed for all copings in both groups. Maximum retentive forces were measured in retentive strength (kgF), with a conversion factor of 9.807 N = 1 kgF.

Results: At each tapered abutment length, the retentive strength increased proportionally and was significantly different, ranging from 31.67 ± 4.10 kgF to 67.68 ± 11.22 kgF (F [5,24] = 20.46, P < .001). An unmodified hexagonal abutment demonstrated the highest retentive strength (70.15 ± 12.97 kgF). The sequential removal of 1, 2, and 3 contiguous vertical axial walls of the hexagonal abutment resulted in retentive strength values of 59.89 ± 10.06 kgF, 57.01 ± 9.62 kgF, and 55.99 ± 9.35 kgF, respectively, with no significant difference (P > .05) in strength.

Conclusions: A partially customized abutment with vertical axial walls on one side and a profile reduction on the opposite side can provide comparable retention to cemented copings at one-third the length and at one-sixth the surface area of an 8-mm abutment with an 8-degree taper.

Purpose: To answer the following question: 'Do recombinant, purified, and concentrated growth factors enhance the regenerative potential of particulate bone graft substitutes in maxillary sinus floor augmentation (MSA)?'

Materials and methods: Human studies comparing histomorphometric data on new bone formation, residual graft material, and fibrous tissue ratio (outcomes of interest) following MSA procedures employing particulate bone grafts/substitutes in combination or not with growth factors were retrieved from PubMed/MEDLINE, Web of Science, Cochrane, and Scopus online databases and complemented with a hand search. Controlled studies published in English up to December 2022 and reporting on histomorphometric data expressed as volume percentage of the outcomes of interest were considered. Risk of bias was assessed, and a meta-analysis was performed to investigate the effects of supplementary growth factors on new bone formation, remaining graft particles, and fibrous tissue ratio.

Results: Data were included from 613 samples in 477 patients reported in 22 publications. Meta-analysis showed that platelet-rich plasma or platelet-rich fibrin resulted in 49% more new bone formation than in control group areas (P = .004), and those areas supplemented with growth factors presented 57% less residual graft particles after healing (P < .0001). A significant (P = .03) 1.85-fold increase in connective tissue formation was noted in areas treated with recombinant human bone morphogenetic proteins (rhBMPs) after healing.

Conclusions: Selective supplementary growth factors may enhance new bone formation and accelerate particulate graft turnover, while rhBMP may significantly increase connective tissue formation in MSA procedures in humans.

Purpose: To assess the survival of double-crown-retained implant-and-tooth-supported removable partial dentures (DCR-ITSRPDs), evaluate abutment survival, and identify first aftercare measures.

Materials and methods: The influence of various factors on the survival of the DCR-ITSRPDs and the abutments were observed in this retrospective and clinical follow-up study using the Kaplan-Meier estimate. In addition, the first-required aftercare measure for each prosthesis was evaluated.

Results: In total, 47 DCR-ITSRPDs were investigated (mean observation: 4.3 ± 3.8 years; max: 14.3 years), 3 of which (6.4%) had to be replaced. The survival probability for DCR-ITSRPDs was 100% at 5 years and 75% at 10 years. A total of 297 abutments (120 natural teeth and 177 dental implants) were observed, 22 of which (7.4%; 6 teeth and 16 implants) failed. The survival probability for teeth was 90.2% at the 5- and 10-year mark; for dental implants, it was 90.4% at 5 years and 76.3% at 10 years.

Conclusions: DCR-ITSRPDs are a successful and durable treatment option for patients with substantially reduced residual dentitions. Both prostheses and abutments show good survival times after 5 and 10 years in function. The patient-associated factors tested showed no influence on the survival of DCR-ITSRPDs and abutments. Peri-implant infection was the decisive factor for abutment loss; therefore, regular dental prophylaxis and examinations are of major importance.

Purpose: To quantify the clinical accuracy of a robotically assisted implant guidance system in partially edentulous patients without the use of postoperative CBCT.

Materials and methods: A total of 10 implants (7 patients) were placed in partially edentulous patients utilizing a robotically assisted implant guidance system. Following the implant placement, an intraoral scan was performed to register the implant position after attaching a scan body. The virtual plan and the postoperative intraoral scan with the scan bodies were exported as STL files and superimposed, and discrepancies were analyzed using Geomagic Control X software. Positional deviations were measured between the midpoint of the platform and apex of the planned and achieved implant positions.

Results: Seven of the 10 implants in this study were defined as fully robotically guided, while 3 were partially robotically guided. For the fully robotic dynamically guided group, the mean deviation at the midpoint of the restorative platform of the implant, the apex of the implant, the top of the scan body, and the mean angular deviation were 1.31 ± 0.46 mm, 1.58 ± 0.61 mm, 1.11 ± 0.57 mm, and 2.34 ± 1.71 degrees, respectively. For the partially robotic dynamically guided cases, these values were 1.31 ± 0.49 mm, 1.45 ± 0.3 mm, 1.74 ± 0.47 mm, and 3.75 ± 2.53 degrees, respectively. Eight of the 10 implants (irrespective of full or partial guidance) showed a buccal displacement.

Conclusions: Robotic surgery offers a level of accuracy similar to fully guided implant placement, without the need for a physical template, and allows for changes in the surgical plan at any time. The analytical method described in this study is an effective and radiation-free quality-control tool that can be used in implant dentistry as well as in other areas of dental research.

Purpose: To assess the healing process of the extraction socket and the dimensional changes that occur after alveolar ridge preservation utilizing a polylactide-co-glycolide scaffold (PLGA).

Materials and methods: The present study involved the extraction of 28 teeth from 14 patients. The total number of sockets was 28, which were divided into two groups consisting of 14 test sockets and 14 control sockets. The study group (SG) was subjected to socket preservation with a PLGA scaffold while the control group (CG) was left for spontaneous healing. The dimensions were measured before and after operation at 1, 3, and 5 mm below the alveolar crest horizontally and the height of buccolingual bone vertically.

Results: According to the histologic analyses, the PLGA scaffold was resorbed within 4 months. CBCT imaging revealed a decrease in the horizontal crest dimension at three distinct coronoapical levels in SG, measuring 2.05 ± 1.05 mm at -1 mm, 1.51 ± 0.89 mm at -3mm, and 0.92 ± 0.7 mm at-5mm.CG showed readings of 1.22 ± 1 at-1mm, 0.92 ± 0.67at-3mm, and 0.73 ± 0.69 at -5 mm. In comparison to CG, SG showed a significant reduction in horizontal losses at -1 mm. Vertical crest dimensions decreased by 1.64 ± 1.11 mm for the buccal bone height and by 1.56 ± 1.08 mm for lingual bone height in SG; in CG, the buccal and lingual bone height had mean values of 2.08 ± 1.44 mm and 1.73 ± 1.27 mm, respectively. There was no statistically significant difference observed in the vertical losses between the groups.

Conclusions: Following a period of 4 months, the PLGA scaffold was completely resorbed. Based on CBCT measurements, horizontal resorption was lower than CG at -1 mm coronally.

Purpose: To investigate the effects of sinus membrane stabilization (via suturing) and dental implant placement on the endo-sinus bone formation in lateral sinus elevations performed without grafting.

Materials and methods: Maxillary sinus elevation surgery using the lateral approach was performed bilaterally on 30 New Zealand white rabbits. The maxillary sinus areas were divided into control and test groups. In the control group, a titanium screw was placed after sinus membrane elevation; in the test group, the sinus membrane was sutured to the lateral walls, and a titanium screw was placed in the center of the alveolar crest. The subjects were sacrificed at 4 and 8 weeks. Then samples were collected, and a microcomputed tomography (micro-CT) analysis was performed. In addition, the volume of newly formed bone, percentage of osseointegration, sinus volume, residual bone height, and implant protrusion length were measured using micro-CT analysis.

Results: The sinus volume, volume of newly formed bone, and percentage of osseointegration in the test group were significantly higher than in the control group at 4 weeks (P = .01, P = .04, P = .02, respectively). While the volume of newly formed bone was 17.1 ± 3.08 mm3 in the control group, it was 26.9 ± 14.26 mm3 in the test group at 4 weeks. The volume of newly formed bone significantly decreased from 26.9 ± 14.26 mm3 to 17 ± 3.66 mm3 at 8 weeks (P = .02). No significant difference in residual bone height was found at 4 and 8 weeks (P = .07). No significant difference in implant protrusion length was found between the control and test groups (P = .18). Protrusion length and new bone formation in the sinus showed a negative relationship (P = .01).

Conclusions: Suturing the sinus membrane to the lateral sinus wall is an effective approach for increasing osseointegration, bone volume, and sinus volume in the short term. A slow-absorbing suture material can be used to maintain sinus and bone volumes in the long term.