Objectives: To compare the accuracy of CAD-CAM and conventional guides in the static computer-assisted implant surgery (sCAIS) placement of distal free-end implants.
Material and methods: A prospective, controlled, and blinded quasi-experimental study was done involving 27 patients (76 implants) distributed into two groups according to the surgical guide manufacturing approach used: conventional (control group [CG]) or CAD-CAM (test group [TG]). The implants were planned in the software and the surgical guides were manufactured. Fully guided implant placement was carried out and the deviations were measured along with secondary variables as potential confounding factors. Descriptive analyses were performed on mean, standard deviation (SD), and interquartile range (IQR). In the comparative/inferential analysis hypothesis, contrasts were made of the quantitative and qualitative variables and multiple linear models were generated to adjust for the different confounding variables recorded.
Results: Coronal horizontal deviation (CHD) was significantly greater in CG (1.52 mm) versus TG (1.04 mm) (p = 0.004). Apical horizontal deviation (AHD) in turn was 1.67 versus 1.46 mm, respectively; angular deviation was 2.87 versus 3.64; and vertical deviation was -0.1 versus -0.05 mm, with no significant differences between the groups (p > 0.05). A greater sleeve height, positioning in premolars versus molars, and the use of shorter implants, were associated with greater accuracy in relation to CHD and/or AHD (p < 0.05). The implant success rate at 1 year was 92.1%, 90.7% in TG, and 100% in CG, being statistically significant (p = 0.026) at the implant level, but not significant at the patient level.
Conclusions: The CAD-CAM surgical guides proved to be more accurate than the conventional guides in the sCAIS placement of distal free-end implants, with statistically significant differences being observed in terms of CHD. All implant failures occurred in TG (6 implants/3 patients).
Trial registration: ClinicalTrials.gov identifier: NCT06404385.
The objective of this study is to compare the effect of the location of recombinant human bone morphogenetic protein 2 (rhBMP-2) from the native bone and the periosteum for vertical alveolar bone augmentation.
Mandibular, chronic, standardized, bilateral, and vertical defects in 12 beagle dogs were evaluated using four modalities: a xenograft alone (XENO; n = 6); rhBMP-2 alone (BMP; n = 6); a technique with rhBMP-2 close to the host bone covered by xenograft (SAN; n = 6); and a technique with rhBMP-2 close to the flap on top of the xenograft (LAS; n = 6). After 8 weeks, a series of in vivo inspections, fluorescence microscopy, histologic and histomorphometric evaluations, and micro-CT analyses.
After 8 weeks of healing, new bone formation correlated with proximity of rhBMP to the perforated membrane with BMP and LAS (p = 0.024). The highest total bone volume was found in the LAS group (45.1% ± 13.3%), followed by the SAN group (35.2% ± 6.7%), BMP group (33.1% ± 11.8%), followed by the XENO group (23.1% ± 6.5%). The SAN group demonstrated frequent seroma formation. Blood vessel formation was more pronounced in the LAS + rhBMP group, with a significant increase of 27.1% compared to the XENO group (p = 0.02). Micro-CT revealed a strong trend for higher bone volume in the BMP group (34.7%) compared to the XENO group (13.6%) (p = 0.06). Only rhBMP-2 groups demonstrated bone formation above the perforated membrane.
The location of rhBMP-2 in relation to the biomaterial and periosteum influenced the effectiveness of vertical bone regeneration.
Objectives: To investigate the reliability and time efficiency of the conventional compared to the automatic artificial intelligence (AI) segmentation of the mandibular canal and registration of the CBCT with the model scan data, in relation to clinician's experience.
Materials and methods: Twenty clinicians, 10 with a moderate and 10 with a high experience in computer-assisted implant planning, were asked to perform a bilateral localization of the mandibular canal, followed by a registration of the intraoral model scan with the CBCT. Subsequently, for each data set and each participant, the same operations were performed utilizing the AI tool. Statistical significance was assessed via a mixed model (using the PROC MIXED statement and the compound symmetry covariance structure).
Results: The mean time for the segmentation of the mandibular canals and the registration of the models was 4.75 (2.03)min for the manual and 2.03 (0.36) min for the AI-automated operations (p < 0.001). The mean discrepancy in the mandibular canals was 0.71 (1.80) mm RMS error for the manual segmentation and 0.68 (0.36) RMS error for the AI-assisted segmentation (p > 0.05). For the registration between the CBCT and the intraoral scans, the mean discrepancy was 0.45 (0.16) mm for the manual and 0.37 (0.07) mm for the AI-assisted superimposition (p > 0.05).
Conclusions: AI-automated implant planning tools are feasible options that can lead to a similar or better accuracy compared to the conventional manual workflow, providing improved time efficiency for both experienced and less experienced users. Further research including a variety of software and data sets is required to be able to generalize the outcomes of the present study.
To determine the effect of polydeoxyribonucleotide (PDRN) on endosinus bone regeneration in a rabbit sinus model at sequential healing time points.
Eighteen New Zealand white rabbits were used. Bilateral sinus floor elevation (SFE) was performed. Two groups were randomly assigned to each sinus: (1) test group, in which SFE was performed using collagenated bone substitute material soaked with PDRN (concentration 2.0 mg/mL, dose 0.5 mL), and (2) control group, in which SFE was performed using collagenated bone substitute material only. The experimental animals were sacrificed at 2, 4, and 8 weeks (n = 6 at each healing time point). Microcomputed tomography (micro-CT), histologic, and histomorphometric analyses were performed.
The micro-CT analysis revealed statistically significant increases in the mineralized tissue volume between 4 and 8 weeks (p < 0.05). Histologically, no specific intergroup difference was found in the pattern of new bone formation. Histomorphometrically, the area of newly formed bone (NB) was larger in the test group than in the control group at all healing time points (1.4 vs. 1.2 mm2 at 2 weeks, 3.4 vs. 1.9 mm2 at 4 weeks, and 5.7 vs. 4.5 mm2 at 8 weeks; median value), but the difference was statistically significant only at 4 weeks (p < 0.05). NB in set regions of interest (ROI_C, ROI_W, and ROI_M) tended to be greater in the test group than in the control group without statistical significance (p > 0.05).
PDRN appeared to enhance new bone formation at all healing time points, but the improvement was statistically significant only at 4 weeks.
To determine the in vitro effects of minocycline on human gingival fibroblasts (HGFs), its clinical impact on early wound healing after implant placement, and its potential mechanism of action.
First, we evaluated the in vitro proliferation, migration, and collagen production of HGFs treated with different concentrations of minocycline, as well as the underlying mechanism. Subsequently, we conducted a clinical trial and randomly assigned 40 partially edentulous patients to either the test (minocycline hydrochloride treatment) or control (blank control) group immediately after implant surgery. The early wound healing score (EHS), pain index, gingival index (GI), modified sulcus bleeding index (mSBI), and peri-implant crevicular fluid samples were assessed or collected 3 and/or 7 days after surgery.
In vitro, 1 μg/mL minocycline promoted the proliferation, migration, and collagen production of HGFs. Minocycline inhibited collagen degradation by downregulating the expression of matrix metalloproteinase-2 (MMP-2) and MMP-14 and upregulating tissue inhibitors of metalloproteinases-2. However, higher concentrations of minocycline, 10 and 100 μg/mL, exhibited adverse effects. In the randomised clinical trial, the test group showed significantly better clinical outcomes compared to the control group, with higher EHS and lower GI, mSBI, concentrations of IL-1β, IL-10, and TNF-α, and relative abundance of Streptococcus and gram-negative anaerobic bacteria.
Small doses of minocycline (1 μg/mL) promoted the proliferation and migration of HGFs and inhibited collagen degradation in vitro. Locally delivered minocycline after implant surgery improves clinical outcomes by promoting early wound healing, relieving the inflammatory response, and decreasing early colonisation of gram-negative anaerobic bacteria.
This clinical trial was registered in the Chinese Clinical Trial Registry (registration number: ChiCTR2100044680)
Objective: The objective of this study is to investigate the influence of metal artifact reduction (MAR) on two cone beam computed tomography (CBCT) units in the evaluation of bone graft loss adjacent to titanium (Ti) and zirconium (Zr) implants.
Material and methods: Twelve Ti and twelve Zr implants were placed in the posterior region of dry human mandibles. Bone graft was applied to the level of the cover screw. Bone graft loss was simulated in half of the sample (6 Ti and 6 Zr) by removing the graft material up to the third implant thread on the buccal surface. CBCT images were acquired on two units, varying the application of MAR (OP300-off and on; Eagle 3D-standard, intermediate, and extreme). The images were assessed by five evaluators that scored the presence of graft loss according to a 5-point scale. The diagnostic values were calculated and compared by non-parametric tests with a significance level of 5%.
Results: Higher diagnostic values were achieved with MAR activated in the OP300 unit, for Ti and Zr (p < 0.05). On the Eagle 3D unit, MAR in extreme mode resulted in lower diagnostic values for both types of implants (p < 0.05). The diagnostic values of Ti implants were higher than Zr implants (p < 0.05).
Conclusion: The application of MAR influences the diagnosis of bone graft loss adjacent to Ti and Zr dental implants. However, the extreme mode of MAR in the Eagle 3D unit can impair the diagnostic task in both types of implants and should be avoided.
This retrospective study aimed to evaluate the clinical outcomes associated with zygomatic implant (ZI) rehabilitation in partially atrophic edentulous maxillae over a mean follow-up period of more than 10.3 years.
All consecutive patients underwent ZI rehabilitation between 1999 and 2020, with a minimum follow-up period of 3 years. The primary outcome was the implant survaival rate. Secondary outcomes included the prosthesis success rate, complications, and Oral Health-Related Quality of Life.
Of the 21 patients, treated with 27 ZIs and 48 conventional implants (CIs), 9 (42.9%) were females. The mean follow-up was 10.3 ± 5.7 years (range 3.2–23.4). ZI and CI survival rates were 100% and 97.9%, respectively, with one CI that failed. Eleven patients received 12 CIs placed in the pterygoid and tuberosity region. Most of the implants (81.33%) were immediately loaded, with 17 patients (80.9%) receiving 21 acrylic bridges. Of the total of 26 definitive prosthesis, the success rate was 96.1%. Local inflammation (n = 2) and soft tissue recession (n = 1) were reported as complications, occurring at a mean follow-up of 4.5 and 3.2 years, respectively. The mean score of the OHIP-14 questionnaire was 1.19 ± 1.99.
Unilateral ZI rehabilitation was a predictable option for patients with partially atrophic edentulous maxilla who have experienced previous graft or implant failures, or who require immediate loading. Splinting the ZI with CI for restoration appeared to be essential in unilateral ZI treatment. Complications were infrequent and could be managed effectively, with patient-reported outcomes indicating normalization in quality of life.
The objective of this study was to compare open versus closed healing of soft and hard tissue following alveolar ridge preservation (ARP) procedures in damaged extraction sockets.
ARP was performed in five mongrel dogs using collagenated deproteinized bovine bone mineral (cDBBM) and a resorbable non-cross-linked collagen membrane (NCCM) in damaged extraction sockets, with each socket entrance left either open (open group) or closed (closed group). Clinical wound epithelization at the socket entrance and the dimensions of keratinized tissue were evaluated over time. Additionally, the augmented ridge dimensions and new bone formation were assessed radiographically and histologically at 8 weeks after surgery.
The dimensions of the socket entrance gradually decreased in the open group, and wound epithelization was almost complete within 4 weeks. The mucogingival junction was maintained more apically in the open group than in the closed group (0.14 ± 0.40 mm vs. −0.86 ± 0.71 mm [mean ± SD], p < 0.05). The augmented ridge dimensions did not differ significantly between the open and closed groups (93.1% ± 5.4% vs. 88.3% ± 11.2%, p > 0.05). Histological analyses revealed no significant differences in the amount of newly formed bone. However, membrane resorption in the crestal region was more pronounced in the open group.
Open and closed healing approaches for ARP in extraction sockets with damaged buccal wall resulted in similar ridge dimensions and new bone formation. However, there was less reduction of the buccal bone crest and wider keratinized tissue width after open healing.
To evaluate and compare the accuracy of task-autonomous robot-assisted implant surgery (RAIS) and dynamic computer-assisted implant surgery (dCAIS) for zygomatic implant placement.
Ten atrophic edentulous maxilla models requiring zygomatic implant (ZI) placement were randomly divided into the RAIS and dCAIS groups. Osteotomies and implant placement were performed under the guidance of a task-autonomous robotic system or dynamic navigation system. A total of 20 ZIs were analyzed. The angular, coronal, lateral coronal, coronal depth, apical, lateral apical, and apical depth deviations were measured and analyzed between the two groups. The primary outcome parameters were the angular deviations between the planned and the placed ZIs. Data was subjected to descriptive and comparative statistical analysis. The significance of inter-group differences for continuous variables was assessed with Student's two-sample t-tests, Welch two-sample t-tests, and Mann–Whitney U tests according to the distribution normality and variance homogeneity.
ZI placement deviations were compared between the RAIS and dCAIS groups, showing a mean angular deviation of 0.92 ± 0.40° versus 2.03 ± 0.53° (p < 0.001), a mean (±SD) coronal deviation of 0.48 ± 0.25 mm versus 1.29 ± 0.46 mm (p < 0.001), and a mean apical deviation of 0.88 ± 0.28 mm versus 1.96 ± 0.46 mm (p < 0.001).
For computer-guided ZI placement, task-autonomous RAIS was superior to dCAIS in terms of accuracy.
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