This study aimed to evaluate the impact of different collagen membran fixation protocols on the volume stability in horizontal ridge augmentation in the aesthetic area.
A total of 48 patients with 65 augmented sites were included in this study. Implants were placed in the aesthetic region, and simultaneous guided bone regeneration (GBR) surgery was performed for horizontal ridge augmentation. Participants were divided into four groups, each comprising 12 patients, based on different absorbable collagen membrane fixation protocols. Group 1: without fixation; Group 2: fixation with absorbable sutures; Group 3: fixation with titanium pins; Group 4: fixation with titanium pins and absorbable sutures. Cone beam computed tomography (CBCT) was performed immediately after surgery and at 6 months post-surgery, respectively. The horizontal thickness of the augmented region was analyzed for volume stability at the implant shoulder (H0) and 1–5 mm apical to the implant shoulder (H1–H5). Changes in labial thickness during bone healing were calculated as absolute values (mm) and relative values (%).
After 6 months of bone healing, horizontal thickness was significantly reduced at all levels (H0–H5) in all groups compared to immediate post-surgery results (p < 0.05). At H1–H5, horizontal bone loss in group 1 was significantly higher than in the other three groups (p < 0.05). Group 4 exhibited significantly less horizontal bone loss compared to group 2 at H0–H2 (p < 0.05) and group 4 compared to group 3 at H0–H1 (p < 0.05). No significant difference in horizontal bone loss between groups 2 and 3 was detected at H0–H5 (p > 0.05).
Guided bone regeneration in the aesthetic area with additional membrane fixation demonstrated superior volume stability of the augmented region compared to cases without fixation. There was no significant difference in bone volume stability between membrane fixation with titanium pins and fixation with absorbable sutures. However, the combined use of pins and absorbable sutures yielded superior volume stability.
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.
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.
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.
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.
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.
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).
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.
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.
This study investigated the accuracy of robotic computer-assisted implant surgery (r-CAIS) for immediate implant placement.
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.
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.
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.
To reveal the force profiles recorded by haptic autonomous robotic force feedback during the transcrestal sinus floor elevation (TSFE) process, providing a reference for the surgery strategy during TSFE.
A total of 42 maxillary sinus models with different angles of the sinus floor (30°, 40°, 50°, 60°, 70°, 80°, and 90°, compared to vertical plane) were 3D printed. Implant site preparation was performed using a robotic system, and the total force (Ft) and axial force along the drill (Fz) during the surgery were recorded by the haptic robotic arm. The actual initial breakthrough point (drill contacting sinus floor) and complete breakthrough point (drill penetrating the sinus floor) were defined visually (the actual IBP and the actual CBP). The theoretical initial breakthrough point (the theoretical IBP) and the theoretical complete breakthrough point (the theoretical CBP) defined by the robot-guided system and the CBCT were determined by real-time force feedback and imaging distance measurement, respectively. The distance from the bottom of the resin model to the actual IBP and the actual CBP was defined as Di and Dt, respectively.
The difference in Fz began to increase significantly at 70°, while the difference in Ft became significant at 60°. When the angle was greater than 70°, there was no significant difference in the discrepancy between the actual and theoretical perforation points. Compared to judging the breakthrough point by CBCT, real-time force feedback TSFE under robotic surgery achieved more accurate initial breakthrough point detection.
The smaller the angle, the larger the breakthrough force for the drill. The real-time force feedback of haptic robotic system during TSFE could provide reliable reference for dentists. More clinical studies are needed to further validate the application of robotic surgery assisted TSFE.
This experiment aimed to observe the differences in biological properties by producing BGS-7 + PCL scaffolds with different weight fractions of BGS-7 through 3D printing and to confirm whether using the scaffold for vertical bone augmentation is effective.
Cube-shaped bioglass (BGS-7) and polycaprolactone (PCL) scaffolds with different weight fractions (PCL alone, PCL with 15% and 30% BGS-7) are produced using 3D printing. The surface hydroxyapatite (HA) apposition, the pH change, proliferation and attachment assays, and various gene expression levels are assessed. After a 7-mm implant was inserted 3 mm into the rabbit calvaria, vertical bone augmentation is performed around the implant and inside the scaffold in four ways: scaffold only, scaffold+bone graft, bone graft only, and no graft. Sacrifice is performed at 6, 12, and 24 weeks, and the various parameters are compared radiographically and histologically.
HA apposition, cell proliferation, cell attachment, and expression of osteogenic genes increase as the proportion of BGS-7 increase. In the in vivo test, a higher bone–implant contact ratio, bone volume ratio, bone mineral density, and new bone area are observed when the scaffold and bone grafts were used together.
The 3D-printed scaffold, a mixture of BGS-7 and PCL, exhibit higher biological compatibility as the proportion of BGS-7 increase. Additionally, the use of scaffold is effective for vertical bone augmentation.
To evaluate the effects of repeated abutment manipulation on the prevalence of peri-implant diseases.
A total of 27 edentulous patients (n = 108 implants) immediately restored with double-crown retained implant-supported prostheses were identified for this retrospective study. The test included the one-abutment, one-time care concept (n = 18 patients, n = 72 implants, OAOT) and the control abutment replacement (n = 9 patients, n = 36 implants, AR). A mixed effects model regression was conducted for the variable diagnosis (healthy, peri-implant mucositis, and peri-implantitis) with predictors abutment replacement (presence/absence), number of abutment replacement, category of keratinized mucosa (KM) (2 < KM ≥2 mm), and radiographic bone loss (BL).
After 3–15 years (mean 10.2 ± 2.8 years), the prevalence of peri-implant mucositis and peri-implantitis in patients in the AR group was 11.1% and 88.9%, corresponding to 22.2% and 55.6% at the implant level, respectively. In OAOT group, none of the implants showed peri-implant mucositis, whereas the prevalence for peri-implantitis at patient and implant level amounted to 5.6% and 5.6%, respectively. The increased number of abutment replacements was significantly associated with the increased probability to diagnose peri-implant mucositis and peri-implantitis (OR: 6.13; 95% CI [2.61, 14.39]) (p < 0.001), whereas the presence of keratinized mucosa was not founded as a significant cofounder. The estimated mean BL in AR group was 1.38 mm larger than in OAOT group (p = 0.0190).
The OAOT concept was associated with a lower prevalence of peri-implant diseases.
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