Journal of Prosthodontics-Implant Esthetic and Reconstructive Dentistry最新文献

Purpose: To assess the precision of implant placement when comparing tilted orientations to axial orientations, utilizing a fully guided surgical protocol in an edentulous mandibular model.

Materials and methods: Fourteen rubber-coated mandibular models were scanned with fiducial markers using a commercial benchtop surface scanner, followed by cone beam computed tomography for implant planning through a dual-scan protocol. The models were randomly divided into control and experimental groups. In the control group, each model was planned for four axially oriented implants. Conversely, the experimental models were planned for two axially oriented implants near the lateral incisors and two posteriorly tilted implants at a 30-degree angle. A mucosal-supported, pin-retained surgical guide was designed and 3D-printed, facilitating the fully guided implant placement. All implants received scan bodies and were rescanned for evaluation of the trueness between the planned and the actual implant location using the implant planning software. Mixed model ANOVA was used to detect differences between groups with regards to angular deviation, offset at base, and offset at tip.

Results: A total of 56 implants were placed across all models. Fourteen posterior implants in each group served as control and experimental conditions, while the remaining 28 anterior implants acted as secondary control. No significant differences were observed between the experimental and control groups in terms of angular deviation (p = 0.7001), offset at base (p = 0.6409), or offset at tip (p = 0.6931). Analysis comparing anterior implant deviations between groups and anterior to posterior implant deviations within the control arches also was not significant. However, secondary analysis revealed a significant difference between anterior and posterior implants within the experimental group for offset at base (p = 0.0087) and offset at tip (p = 0.0288).

Conclusions: Despite the limitations inherent to a benchtop study, the findings suggest that there are no statistically significant 3D deviations at the base or apex, nor in angular deviations, when comparing tilted and axial implant placements using a digital workflow and fully guided protocols in an edentulous model.

Purpose: To evaluate the longevity of terminal abutment teeth retaining maxillary obturator prostheses.

Materials and methods: This was a retrospective study of patients who underwent maxillectomy followed by delivery of definitive obturator prostheses between 1994 and 2020. Details on patient demographics, primary tumor, and radiation therapy were collected. The tooth closest to the defect was identified as the terminal abutment, and information such as tooth type, condition of tooth at the time of maxillectomy, Aramany classification, and cause of abutment loss were noted from the dental charts. Survival time of the terminal abutment tooth was calculated from the date of maxillectomy to the last dental follow-up visit or the date of abutment loss. Univariate analyses were performed to test for the association between survival time and each of the four covariates.

Results: In the 26-year study period, 148 teeth in 130 patients met the inclusion criteria. Ninety-eight (66.2%) terminal abutment teeth survived, and 50 (33.8%) were lost. Squamous cell carcinoma was the leading tumor diagnosis (51%). Aramany Class II was the most predominant arch configuration (51%). The majority of the terminal abutment teeth were maxillary incisors (43%). The chief cause of terminal abutment loss was bone loss and mobility (46%). The 10-year survival probability was 65%. Radiation therapy did not statistically contribute to terminal abutment loss. Terminal abutment teeth with dental treatment showed higher failure than those without any prior treatment or dental disease.

Conclusion: Clinicians must be aware of the various factors affecting the survival of terminal abutment teeth which can ultimately affect the success of the maxillary obturator prostheses.

Purpose: To assess the accuracy of intraoral scanners (IOSs) for final impressions using dual-purpose scan jigs (DPSJs) and standard scan bodies (SBs).

Materials and methods: An edentulous typodont model with multiunit abutment analogs in the lateral incisor (L), premolar (P), and molar (M) regions was used for intraoral scanning following the manufacturer's recommended protocol. This process involved digitally scanning standard SBs and DPSJs, with the obtained data superimposed and compared against the reference model. Three-dimensional (3D) evaluation software (Geomagic Control X) was then employed to identify any deviations in the data, followed by statistical analysis using ANOVA one-way tests and Bonferroni post hoc tests to determine differences at each location.

Results: The overall accuracy ranged from 21.8 to 16.8 µm for DPSJs and from 25.3 to 16.1 µm for SBs. Statistical analysis showed no significant differences between DPSJs and SBs across lateral incisor (L), premolar (P), and molar (M) locations. Specifically, SBs exhibited higher accuracy in lateral incisors (16.8 µm) compared to DPSJs (21.8 µm), but this difference lacked statistical significance. Similarly, in premolar locations, SBs were slightly more accurate (16.1 µm) than DPSJs (17.3 µm), with no statistical significance. Conversely, DPSJs showed slightly better accuracy in molar locations (17.3 µm) than SBs (19.1 µm), which was not statistically significant.

Conclusion: The in vitro study concluded that intraoral digital scanning with DPSJs showed comparable accuracy to standard scan bodies for fully edentulous arches. Furthermore, the 3D deviation of implant positions using both DPSJs and SBs fell within clinically acceptable ranges.

Advancements in microvascular free-flap surgery and virtual surgical planning (VSP, 3D Systems) have allowed significant development in immediate reconstruction and dental rehabilitation of maxillofacial defects. These techniques are commonly utilized for dental rehabilitation of ablative defects of the head and neck affected by pathology. The widespread use of the Jaw-in-a-Day protocol has shown to be a feasible and predictable way to immediately reconstruct and dentally rehabilitate in one surgery. However, the literature on applying these advanced techniques in the trauma setting is limited. Furthermore, there are few reported cases in which a Jaw-in-a-Day protocol is used in conjunction with the full arch dental rehabilitation of the opposing jaw. In this scenario, restoring just one arch would not restore a fully functional occlusion. This case report describes a concomitant mandibular Jaw-in-a-Day with a maxillary All-on-4 in one surgery for a patient who sustained severe facial trauma from a self-inflicted gunshot wound.

Purpose: This study evaluated the accuracy (trueness and precision) of facial scanners using different technologies and the reliability of the texture maps produced.

Materials and methods: A volunteer was scanned using nine scanners: Cloner, Artec MHT, Revopoint Mini, Revopoint POP 2, Vectra H2, EXAscan, Scaniverse app, iPhone 13 Pro MAX, and Nikon Z 7II Camera. Eighty scans were compared to a reference model (Vectra XT). Root mean square and standard deviation of the dimensional discrepancies were analyzed using ANOVA and Tukey post-hoc test. Acquisition times were assessed using Kruskal-Wallis test followed by Mann-Whitney U-test. Two expert assessments on texture map realism were averaged and compared to the reference using one sample t-test. The two experts' intraclass correlation coefficient (ICC) was calculated.

Results: Eight scanners fully captured the three-dimensional facial geometry. Overall trueness and precision of the facial scanners were significantly different (p < 0.001). Seven scanners showed clinically acceptable scanning accuracy of less than or equal to 2 mm. Cloner displayed the lowest deviation (0.61 ± 0.08 mm), fastest acquisition time (0.40 ± 0.00 s), and was highly reliable (<1 mm). The texture map of the Vectra H2 had the highest mean score of 8.50 and was the most realistic. The ICC between the experts was 0.78 indicating good interexaminer reliability.

Conclusions: The more economical facial scanners within each scanning technology (iPhone 13 Pro MAX, Cloner, Revopoint MINI, and Scaniverse app) showed clinically acceptable accuracy with realistic texture maps for facial scanning and therefore could be eligible substitutes for professional higher-cost scanners.

Purpose: To compare masticatory function and patient satisfaction with removable partial dentures (RPDs) with cobalt-chromium (Co-Cr) and injected polyetheretherketone (PEEK) frameworks, respectively.

Materials and methods: Twelve volunteers (7 women, 5 men; mean age, 56.6 years) with complete maxillary edentulism and partial mandibular edentulism (Kennedy Class I) first received new RPDs with PEEK (experimental group) or Co-Cr (control group) frameworks and used them for 2 months. Masticatory performance (MP) was evaluated using sieves and Optocal, with results expressed as the mean particle size (X₅₀); maximum bite force (MBF) was measured with a force transducer and pressure sensors; and self-reported satisfaction was assessed using a visual analog scale. After the initial evaluation, a 1-week washout period was followed by group crossover and reassessment after an additional 2 months. Data were analyzed using independent-samples t-tests (α = 5%).

Results: X₅₀ values were lower for RPDs with Co-Cr frameworks than for those with PEEK frameworks (p = 0.007), indicating better MP. The MBF did not differ significantly between RPD framework types. Participants' satisfaction, in terms of prosthesis stability (p = 0.02) and chewing ability (p < 0.001), was greater for Co-Cr RPDs. Most participants preferred to continue using Co-Cr frameworks.

Conclusions: RPDs with injected PEEK frameworks were associated with reduced MP and patient satisfaction relative to Co-Cr frameworks.

Purpose: This feasibility study aimed to develop and evaluate a novel implicit neural network (INN)-based model for the automatic reconstruction of biomimetic maxillary molar.

Material and methods: A total of 500 sets of full dental scans containing intact right and left maxillary first molars (#3 and #14) and adjacent teeth were included in this study. The digital maxillary casts were duplicated: one set served as the original, while the other had one maxillary first molar removed. Two INN-based models were developed, including the point convolution for surface reconstruction (POCO-only) model and the POCO with point multilayer perceptron (POCO-PointMLP) model. Each model was trained with either 12,000 or 50,000 sampling points from the training dataset. Chamfer distance (CD), F-score, and Volumetric Intersection over Union (volumetric IoU) were used to evaluate the INN-based models and training outcomes. The best INN-based model was selected to generate 20 digital crown designs (GCs) automatically from randomly selected test datasets and compared with the digital crowns designed by experienced human laboratory technicians (TCs). Both GCs and TCs were compared with the original clinical crowns (OCs) using root mean square (RMS) and color maps. Comparisons of RMS values were analyzed utilizing paired t-tests with statistical significance set at α = 0.05.

Results: The performance of 2 INN-based models and training outcomes were evaluated and POCO-PointMLP trained with 50,000 sample points showed the best outcomes, with CD of 0.000119403, F-score of 0.919740566, and volumetric IoU of 0.943382978. This INN-based model was then selected to generate 20 digital crown designs (GCs) and compared with TCs for the RMS outcomes. The GCs exhibited numerically lower mean RMS compared to TCs without significant difference (0.2839 ± 0.0307 versus 0.3026 ± 0.0587 mm, p = 0.202). GCs and TCs both closely matched to the original clinical crowns (OCs).

Conclusions: This study demonstrated the feasibility and accuracy of the proposed INN-based POCO-PointMLP model for automating the digital crown designs of maxillary first molars. The INN-based model-generated digital crown designs showed comparable 3D deviations to the ones designed by experienced human laboratory technicians, presenting a novel and efficient artificial neural network architecture for tooth digital design tasks with the expansion of training datasets, refined training hyperparameters, and integrated comprehensive assessments.

Purpose: To investigate the impact of zirconium dioxide nanoparticles (nano-ZrO₂) addition to hard and soft liners on the surface roughness and Candida albicans adhesion.

Materials and methods: Nano-ZrO₂ was added to hard and soft chairside reline material in two concentrations (2% wt. and 4% wt.) while an unmodified group of each liner acted as a control, (n = 10). Disc-shaped (10 × 1.3 mm) specimens of hard denture reline (N = 60) and soft denture reline (N = 60) materials were prepared (30/test). A noncontact profilometer was used for surface roughness measurement. A colony-forming unit (CFU/mL) was used to evaluate Candida albicans adhesion. Data was analyzed using ANOVA and a post hoc Tukey's test (α = 0.05).

Results: No significant change in surface roughness was observed with nano-ZrO₂ addition; however, the control groups showed the highest value while 2% nano-ZrO₂ showed the lowest value. In comparison to the control groups, nano-ZrO₂ addition to the hard and soft liners significantly reduced Candida albicans adhesion (p < 0.001), regardless of the concentration.

Conclusion: Incorporating nano-ZrO₂ into hard and soft liner had no effect on surface roughness while its addition reduced Candida albicans adhesion. Using chairside soft and hard liners containing nano-ZrO₂ is recommended to reduce the incidence of denture stomatitis (DS) among denture wearers.

Purpose: Few studies have explored the bone response in dental implant sites prepared using a piezoelectric device, indicating moderate effectiveness in enhancing secondary stability and osteogenesis. This study seeks to expand our understanding of the changes in biological, clinical, and radiographic parameters, during the initial phases of osseointegration in sites prepared with piezoelectric surgery.

Materials and methods: Two implant sites were prepared in the tibia of four minipigs. At the time of implant placement (T0), bone cortex thickness and Implant Stability Quotient (ISQ) were assessed. A bone specimen was collected from the tibia and used as the baseline for biomolecular analyses. X-ray was taken after implant insertion. After 14 days (T14), a computed tomography (CT) scan of the tibias was conducted, and ISQ values were reassessed. Histological and biomolecular analyses were performed on bone sections containing the implant.

Results: ISQ significantly increased from T0 to T14, in the absence of any correlation between the cortical thickness and ISQ. In two animals, CT showed a slight trabecular bone thickening adjacent to the implants and disorganized radiodense spots; in the other two, no trabecular osseodensification was evident. Newly formed bone was about 48% of the tissue around implants. At T14, an increase in osteogenic factors and a decrease in inflammatory molecules were observed.

Conclusion: This study enhances understanding of the biological and clinical responses at bone implant sites following piezoelectric surgery. It highlights the relationship between the rise in certain osteogenic factors and new bone formation, as well as a potential association with increased ISQ.