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

Purpose: Ultra-high translucency zirconia (UT-Zr) is known for its high esthetic quality; however, its inert surface results in low hydrophilicity and surface energy (SE). To address this limitation, this study proposes an innovative zirconia heat treatment process (ZHTP) and aims to evaluate the effects of ZHTP on the surface characteristics of UT-Zr, offering a novel and practical approach for surface pretreatment in dental practice.

Material and methods: The plate-shaped UT-Zr samples were fabricated. After sintering, the samples without additional staining or polishing were divided into the following nine groups: NT (no additional pretreatment), AB (airborne-particle abrasion), PL (nonthermal plasma), PO (polishing), HPO (fine-polishing), NTH (treat with ZHTP), POPL (PL followed by PO), POH (ZHTP followed by PO), and HPOH (ZHTP followed by HPO). The surface roughness (Ra), microstructure, transmittance, glossiness, wettability, and SE of the samples (n = 10), and statistical analyses were conducted.

Results: AB showed the highest Ra and lowest glossiness (P < 0.05), while HPO and HPOH yielded the smoothest surfaces, with HPOH achieving the highest glossiness (P < 0.05). Although the ZHTP approach slightly improved transmittance, it did not affect the microstructure. PO reduced hydrophilicity and SE (P < 0.05), and HPO slightly increased them. PL significantly enhanced both properties (P < 0.05), and ZHTP also increased them (P < 0.05) to levels similar to PL. Notably, hydrophilicity in nonthermal plasma and ZHTP-treated samples decreased similarly after 24 h.

Conclusions: The ZHTP approach enhances UT-Zr wettability and SE, with slight transmittance improvement. HPOH achieves hydrophilicity and SE comparable to PL, validating ZHTP as a promising strategy for UT-Zr surface optimization in dental applications.

Purpose: This pilot study aimed to compare the flexural strength of Amber Mill CAD to IPS e.max CAD and to determine the impact of different crystallization protocols on the flexural strength of Amber Mill CAD ceramics.

Materials and methods: Amber Mill CAD ceramic blocks of a known Vita Classic shade were selected for testing against control IPS e.max CAD blocks of the same shade. Four different translucencies were selected for Amber Mill CAD blocks: high translucency (HT), medium translucency (MT), low translucency (LT), and medium opacity (MO). Two different translucencies were selected for IPS e.max CAD blocks: HT and LT. The partially crystallized blocks were sectioned and placed into six groups for each temperature protocol for a total of 36 samples for Amber Mill CAD and 18 samples for IPS e.max CAD. The samples were sectioned at a thickness of 1.5 mm to simulate the material thickness recommended by the manufacturer for posterior lithium disilicate (LD) crowns. Four crystallization protocols, as recommended by the manufacturer, were used with Amber Mill CAD blocks, and one crystallization protocol was used with IPS e.max CAD blocks. The samples from each group were subjected to 3-point bending test. A two-way analysis of variance (ANOVA) and Tukey pairwise comparison tests were used for statistical analysis and interpretation of collected data.

Results: The mean averages of maximum flexural strength for Amber Mill CAD samples were 269.54 MPa, 280.10 MPa, 277.55 MPa, and 254.16 MPa for HT, MT, LT, and MO, respectively. The mean averages of maximum flexural strength for the IPS e.max CAD samples were 302.99 MPa and 283.49 MPa for HT and LT, respectively. No significant differences in the mean average flexural strength were found between the Amber Mill CAD and IPS e.max CAD blocks (p > 0.05). Further, there were no statistical differences in flexural strength between the four crystallization protocols of Amber Mill CAD (p > 0.05).

Conclusion: Amber Mill CAD shows similar flexural strength to IPS e.max CAD. Further, altering crystallization protocols of the same shade to obtain different translucencies did not affect the flexural strength of Amber Mill CAD.

Purpose: To compare the effect of post-and-core material type and production technique on the fracture resistance of teeth.

Materials and methods: Sixty human maxillary central incisors were used for the study. Root canal treatments were performed, and the post cavities were created. The teeth were divided into six groups (n = 10) according to post material and production method: prefabricated glass-fiber post (PF), zirconia post (PZ), titanium post (PT), and CAD-CAM produced glass-fiber post (CF), zirconia post (CZ), titanium post (CT). All post-and-core restorations were luted with resin cement (RelyX U200). Static loading was applied on the luted metal copings using a universal testing machine to measure fracture resistance. The effect of material and production method on fracture resistance was evaluated with two-way ANOVA test. Tukey HSD test was used in post hoc analyses. Significance was evaluated at p < 0.05 level.

Results: In the CAD-CAM post-and-cores, the fracture resistance of zirconia was significantly higher (809 N) than titanium (569 N) and glass-fiber (342 N). In the prefabricated posts, the fracture resistance of zirconia was significantly higher than glass-fiber (445 N), while there was no significant difference between zirconia (605 N) and titanium (538 N) materials.

Conclusion: Zirconia posts demonstrated the highest and CAD-CAM glass-fiber posts demonstrated the lowest fracture resistance compared to other types of post materials. Additional studies are needed to confirm if CAD-CAM glass-fiber posts may be considered an effective alternative treatment.

A long-term successful implant-supported prosthesis requires the creation of a passively fitting framework, based on an accurate intraoral digital implant scan. According to dental literature, splinted implant scan bodies (ISBs) provide higher intraoral scanning accuracy than non-splinted techniques. This technique presents a structured approach for splinting multi-unit abutment scan bodies (MUASBs) using customized manufactured devices to facilitate the recording of definitive intraoral implant scans.

Purpose: To investigate the feasibility and accuracy (trueness and precision) of facial scanning and virtual patient representation (VPR).

Materials and methods: One participant was recruited and informed consent was obtained. VPR was performed 30 times with a custom fabricated intraoral scan body (ISB). Thirteen adhesive markers were added to the face as an extraoral scan body (ESB). Two facial scans were obtained for each VPR using an infra-red laser accessory sensor (Structure sensor; Occipital Inc) mounted on a computer tablet (iPad Pro; Apple Inc), including one with seated ISB and one without ISB. Two maxillary intraoral scans were obtained using an intraoral scanner (Omnicam; Dentsply Sirona) with and without the ISB. All files were imported to a dental software program (exocad; exocad GmbH) and VPR was obtained by aligning the facial and IOS scans using the ISB and ESB as common elements for alignment. Five fiducial face landmarks, four intraoral dental landmarks, and six perioral landmarks were selected for measurements. A total of 32 linear measurements, including 14 face-face (for facial scan accuracy) and 18 face-dental (for VPR accuracy) representing total face, lower face, and perioral regions, were performed directly using a digital caliper (FINO Digital Caliper; FINO GmbH) and virtually on the VPR. Trueness was evaluated by mean absolute difference (MAD) between the virtual and direct measurements, and the standard deviation represented Precision. Statistical analyses were performed with a statistical software package (IBM SPSS Statistics v25; IBM Corp), with α = 0.05. Data were analyzed for normality with Shapiro-Wilk test, and 1-sample t- (or Wilcoxon signed rank test), technical error of measurement (TEM), and relative error magnitude (REM).

Results: The facial scan had 2.04, 1.66, 0.8 trueness, and 1.05, 0.92, 0.91 precision for total, lower face, and perioral regions. VPR had higher MAD (lower trueness) than facial scan, including 3.32, 2.40, 1.21 trueness and 2.2, 1.47, 1.2 precision for total, lower face, and perioral regions. Both TEM and REM were lowest for the perioral region and increased with increasing measurement distance.

Conclusion: Error in face scanning increased with increased distance and intricate details. VPR accuracy was lower than face scan accuracy because of added errors in the alignment process. The investigated VPR workflow might be feasible for treatment planning and smile design. However, it would be unreliable for more demanding prostheses manufacturing purposes.

Purpose: This randomized clinical trial compared 12-month outcomes of narrow platform implants (NP) or regular platform implants (RP) in beds prepared with conventional versus ultrasonic osteotomy and immediately loaded.

Materials and methods: Patients requiring narrow (3.0 mm) or regular (3.75 mm) implants in the upper esthetic zone were randomly allocated for conventional (10 NP, 15 RP implants) or ultrasonic (10 NP, 15 RP) osteotomy. Primary and secondary implant stability, operation time, patient discomfort, and probing depths were evaluated after different time periods.

Results: Implant bed preparation time was longer (p < 0.001) with ultrasonic osteotomy versus conventional drilling (CD) in both RP and NP groups. Post-operative pain was lesser with ultrasonic preparation on postsurgical days 1 (p = 0.022) and 7 (p < 0.001) in the RP group and days 1, 4, and 7 (p = 0.015, p = 0.019, p = 0.003) in the NP group. Secondary stability at 3 months was higher in the NP group with ultrasonic preparation versus CD (p = 0.002). No significant differences in probing depth were found between 3 and 12 months in either group with either technique. The 12-month success rate was 100% in both groups with both preparations.

Conclusions: Regular diameter implants in beds prepared by ultrasonic osteotomy have comparable primary and secondary stability to those in beds prepared by conventional osteotomy and can be immediately loaded, showing a similar 12-month success rate. Narrow diameter implants placed in beds prepared by ultrasonic osteotomy have comparable primary stability values to those in conventionally prepared beds, but implant stability quotient values were always insufficient for immediate loading.

Alar webbing is a functional and aesthetic defect of the nasal structure noted in cleft lip and palate patients (CLP), which is thought to be due to a deficiency in nasal lining tissue. Surgical procedures have previously focused on the removal of lining or alar cartilage leading to worse post-operative defects. This case demonstrates a novel technique of releasing the tissue, followed by using a CAD-CAM splint to help mold the tissue during the healing process to better control esthetics, symmetry, and prevent relapse. The release of scarred tissue using a custom CAD-CAM stent is a promising technique that allows for symmetric healing and an overall aesthetic surgical result for patients.