The International journal of prosthodontics最新文献

Purpose: To address the challenges of obtaining accurate digital impressions for the fabrication of fixed restorations on multiple implants in full-arch edentulous cases.

Materials and methods: An approach to the use of extended design scan bodies (EDSBs) and advanced digital technologies in full-arch implant rehabilitation is presented. Clinical and laboratory treatment sequences are illustrated, focusing on intraoral scanning, restorative materials, and digital fabrication techniques.

Results: EDSBs provide accurate digital impression results, maintaining precision over longer distances and proving effective for both fixed and removable implant restorations.

Conclusions: Using EDSBs with L-shaped and T-shaped extensions creates a stable reference framework during scanning, overcoming the lack of reliable landmarks on edentulous mucosa and enhancing digital impression accuracy and clinical outcomes.

Immediate nonfunctional loading of an implant in the anterior region is a documented treatment modality with high success rates. This therapeutic approach is frequently used to overcome esthetic and functional problems during the provisionalization period but also because it provides better support of peri-implant soft tissues. For that purpose, an implant-supported resin restoration, either traditionally or digitally made, is used. This clinical report describes the modification of a patient's natural tooth, which was previously fractured, to be used as an implant-supported provisional restoration to obtain better esthetics and preservation of the soft tissues in their original, pre-extraction position.

Purpose: To investigate the effect of immediate provisionalization of single-tooth implants at healed sites for peri-implant soft-tissue conditions, focusing on papilla formation around single implants.

Materials and methods: In total, 12 patients received a total of 12 implants in the incisor, canine, or premolar region of the maxilla or mandible at healed sites with immediate chairside provisionalization. After 4 months, the temporary crown was replaced with the permanent crown. After 40 ± 13.1 months, clinical follow-up was conducted, assessing probing pocket depth (PPD), bleeding on probing (BoP), mucosal recession (MR), and width of keratinized mucosa (KM). Papilla index (PI) was determined immediately after implant placement (t0), before removing the temporary crown (t1), 4 weeks after delivery of the definitive crown (t2), and at the final follow-up examination (t3) to evaluate papilla formation and its change over time.

Results: None of the implants were lost. The mean PPD was 2.5 ± 0.39 mm, and BoP of 25% and 3.5 mm of KM were observed at the final follow-up. No implants showed MR. PI increased in all patients from 1.5 ± 0.45 at t0 to 2.4 ± 0.56 at t1, 2.6 ± 0.47 at t2, and 3.0 ± 0 at t3. The increase in PI between t0 and each individual timepoint from t1 to t3 showed statistical significance.

Conclusions: The present results indicate the suitability and benefit of immediate provisionalization to achieve favorable peri-implant soft tissue conditions and papilla formation.

Purpose: To evaluate the prevalence of biologic and technical/mechanical complications in an edentulous older population rehabilitated with complete removable dental prostheses (CDs) and overdentures (toothretained [ODs], implant-retained [IODs]).

Materials and methods: Patient records of adults (> 60 years) rehabilitated with CDs, ODs, and IODs were included. Demographic information (age, sex), information on the prostheses type, number and type of biologic/prosthetic complications, and the number and time of the complications were extracted. Kaplan-Meier model was used for statistical analyses.

Results: A total of 162 patients (mean age: 74.5 ± 9.45 years; n = 224 prostheses: CD = 172, OD = 21, IOD = 31) were included. The average period of function in situ was 19.70 ± 27.66, 32.72 ± 27.84, and 31.73 ± 32.67 months for the CDs, ODs, and IODs, respectively. Five prostheses failed. Survival analysis revealed an overall survival rate (SR) of 97.8%, with individual 5-year cumulative survival probability of 96.1% for CDs, 94.1% for ODs, and 100.0% for IODs. There were no significant survival differences between maxillary and mandibular prostheses within each type of rehabilitation. In the maxilla, no significant differences were found in maintenance visit times due to prosthodontic complications among the different types of prostheses. Patients with mandibular CDs required maintenance visits earlier compared to mandibular ODs (P < .001) and IODs (P < .001). Patients with mandibular ODs also required maintenance visits earlier than those with mandibular IODs (P = .005).

Conclusions: Rehabilitation of the edentulous arches, whether with CDs, ODs, or IODs, is a predictable treatment modality with high SRs. Differences in maintenance visit times were observed, with CDs and ODs in the mandible requiring earlier visits compared to IODs.

Purpose: To evaluate the effect of cheek retractors on the accuracy of capturing peripheral borders in totally edentulous digital scans by comparing the conventional impression technique to digital scans made using two different cheek retractors.

Materials and methods: In total, 16 edentulous maxillary impressions were made using three techniques: (1) the conventional impression technique, using modeling thermoplastic compound and zinc oxide eugenol paste; (2) the digital intraoral scanning technique, using the DIO scan retractor (DIO); and (3) the digital intraoral scanning technique, using the Brånemark lip retractor (BRAN). The control impressions of each patient were poured, scanned using a desktop scanner, and transferred into a 3D-analysis software. DIO and BRAN groups were scanned using an intraoral scanner, imported, and superimposed, using best-fit algorithm on the corresponding control. The root mean square for the whole surface and for particular regions of interest were calculated to assess the degree of trueness. Patient perception of the impression techniques was the secondary outcome. Statistical analyses were performed using one-sample t test and Wilcoxon test (α = .05).

Results: Significant discrepancies were found for BRAN and DIO compared to the control. No significant discrepancies were found when comparing RMS of BRAN and DIO at different regions. Scan retractors had a significant impact on patient satisfaction, with patients preferring DIO.

Conclusions: Edentulous intraoral scans made using cheek retractors had similar deviations when compared to each other but diverged from the conventional impression in the edentulous maxilla. Patient preference for intraoral scans over conventional impressions was confirmed. The use of different retraction methods during intraoral scanning of totally edentulous maxillary arches does not affect the peripheral border registration.

Purpose: To develop a system for assessment of the status of a tooth to receive a full coverage crown and depict it on a measurable scale, and to validate its use by assessing examiner reproducibility.

Materials and methods: The index was developed based on the inputs from experts in the field with a consensus on factors (four periodontal, two endodontic, and four prosthodontic), stages of severity (stage 1 to stage 4), assigned scores, and relative weights pertaining to varied clinical scenarios. Based on the selection of factor-stage combinations, an overall tooth crownability index (TCI) score along with three-factor scores were computed. The validation study included clinical and radiologic assessment of cases based on the index criteria by four independent examiners (periodontist, prosthodontist, endodontist, and general practitioner).

Results: A total of 40 teeth were assessed. The distribution of repeated selection by the examiners was very similar to the initial distribution (kappa = 0.93). There was no statistically significant difference in the mean scores of examiners in TCI and factorial scores. An excellent agreement between the measurements was observed among the examiners (ICC = 0.993; Crohnbach α = .993).

Conclusions: TCI with excellent agreement and good reproducibility among the examiners has been developed for a tooth to receive a full-coverage crown. TCI will serve as a baseline tool in treatment plan decision-making based on the status of the teeth and in research for evaluating the efficacy of various treatment options available (standard criteria for outcome assessment).

Purpose: This study aimed to evaluate the hydrolytic behavior of different computer-aided design/computer-aided manufacturing (CAD/CAM) resin matrix ceramics (RMCs) in different food-simulating liquids (FSLs).

Materials and methods: Five different CAD/CAM blocks, one from polymer-infiltrated ceramic networks (PICNs; Vita Enamic (EN)) and four from resin-based composites (RBCs; Lava Ultimate (UL), Cerasmart (CER), Brilliant Crios (BR), and Block HC (HC)) were selected. Forty specimens were prepared for each material, and they randomly distributed to each FSLs. The specimens were kept in a desiccator initially, then placed in 5 ml of liquid at 37±1°C for 30 days and weighed at various time intervals. Percentage mass change (Mg%), sorption (SP), percentage of liquid absorbed (SP%), solubility (SL), percentage solubility (SL%), and percentage of liquid absorbed by the polymer matrix (SPpm) water absorption of the specimens were evaluated. Significance was evaluated at p<0.05 levels.

Results: Hydrolytic behavior of the materials showed statistical differences in terms of SP, SL, SP%, and SL% values depending on the liquid environment (p=0.001). The highest SP values were obtained from the HC material in saliva, and the lowest values were obtained from the BR in ethanol. The highest SL values were obtained from the CER and EN in heptane, and the lowest values were obtained from the HC in ethanol. However, all results detected in the study remained below the ISO threshold values.

Conclusions: All materials tested exhibited clinically acceptable hydrolytic behavior over the time tested. Not only the material content but also many factors can affect the hydrolytic behavior.

Purpose: The study aims to produce CAD-CAM reference samples for shade communication milled from the material of the restoration zirconia (ZrO2) and zirconia-reinforced lithium silicate (ZLS) and evaluate the color difference with the corresponding conventional Vita Classical (VC) shade tab. Furthermore, it aims to verify the color consistency of the materials.

Materials and methods: Five-five samples were milled out of ZrO2 and ZLS in five different colors and their color parameters were compared with the corresponding VC tabs both visually and digitally. For digital evaluation, images were taken of the samples and VC tabs and analyzed in Adobe Photoshop to extract L*a*b values. Color difference (ΔE00) was calculated using the CIEDE 2000 formula. Multilevel mixed-effects linear regression model was used to derive estimates of the mean ∆E00.

Results: Color difference was significantly higher than 1.8 ΔE00 in the case of all the ZrO2, ZLS A3, B2 and C2 samples. Color difference was also found during the visual comparison. Comparing the same color samples the ΔE exceeded 0.8 in some cases but stayed under 1.8 ΔE00 in every case and showed no color difference visually.

Conclusion: Comparing CAD-CAM samples and VC shade tabs visible and measurable color differences (ΔE00>AT50:50%) were found in the case of all ZrO2 and three out of five evaluated shades of ZLS samples. The color consistency of the blocks was acceptable. Better shade communication thus more reliable shade reproduction is achieved when reference photos are sent with a color sample made from the restoration's material.

Some of the critical clinical challenges encountered in the treatment of adult patients with deep overbite and worn dentition include correction of deep overbite, establishment of an appropriate occlusal vertical dimension (OVD), and maintenance of long-term occlusal stability. Although Angle's Class II division 2-associated deep anterior overbite is common in orthodontic treatment, simple prosthodontic treatment with great improvement of deep anterior overbite and worn dentition is infrequently reported. A 51-year-old man with Class II Division 2 malocclusion presented with hypo-divergent facial pattern, reduced lower facial height, and protuberant lips. Intraoral examination revealed unevenly worn dentition and an Angle's Class II division 2-associated deep and traumatic anterior overbite. Based on the challenges of the presentation, it was imperative to design an protocol to ensure a predictable and favorable prognosis. According to the current protocols, prosthetic treatment of occlusal rehabilitation was applied. Following the 3-month evaluation period using interim prostheses, full-mouth ceramic restorations were completed. Significant post-treatment functional and aesthetic improvements were achieved with resultant stable inter-incisal contacts either immediately after treatment or during the 2-year follow-up period. Full mouth rehabilitation offers brilliant prospects for improved function, enhanced aesthetics, and improved health of the entire stomatognathic system of Angle's Class II division 2 patient associated with deep overbite and worn dentitions.