Prospective 5-year clinical evaluation of posterior zirconia fixed dental prostheses veneered with milled lithium disilicate (CADon).

OBJECTIVE: Bi-layer zirconia-based posterior fixed dental prostheses (FDPs) have reportedly a high incidence of veneering ceramic fractures. The CADon technique employs zirconia frameworks veneered with milled lithium disilicate glass-ceramic to overcome these shortcomings but long-term clinical studies are missing. This study evaluated the clinical efficacy of posterior 3-unit CADOn FDPs over a 5-year period. MATERIALS AND METHODS: A total of 25 patients, 16 male and 9 female with a mean age of 55.6 years, received a total of 25 posterior three-unit CADOn FDPs. Patients were recalled for baseline and for follow-up visits at 6, 12, 24, and 60 months. Parameters evaluated were fracture, marginal adaptation, marginal discoloration, wear, polish, color match, surface staining, and retention of these restorations as well as secondary caries of the abutment teeth. RESULTS: A total of 21 FDPs evaluated at 60-months revealed a 100% survival rate. All evaluated clinical parameters were satisfactory (alpha or bravo) and there was no statistically significant difference at different time points, except for surface staining, which was also worse at 60 months compared to baseline (p  ≤  0.001). CONCLUSIONS: CADOn three-unit posterior FDPs demonstrate excellent fracture resistance after 5 years of clinical function. All evaluated clinical parameters were satisfactory, except for surface stain, which also increased over time. CLINICAL SIGNIFICANCE: Conventionally veneered bi-layer zirconia-based posterior FDPs have limited clinical success. Based on this study, alternative methods such as zirconia frameworks veneered with milled lithium disilicate glass-ceramic provide a viable alternative with excellent long-term clinical outcomes.

Retrospective cohort analysis of maxillary overdentures retained by unsplinted implants.

STATEMENT OF PROBLEM: Implant therapy involving an unsplinted 2-implant-retained overdenture is well defined as a successful treatment for a patient with an edentulous mandible. However, a similar unsplinted implant therapy supporting a maxillary overdenture is not well characterized. PURPOSE: The purpose of this retrospective study was to evaluate maxillary overdentures retained by 4 unsplinted implants measuring implant survival, overdenture survival, and patient-reported outcomes. MATERIAL AND METHODS: Participants who had received an unsplinted implant-retained maxillary overdenture were included in the study. Participants presented for one denture recall appointment, during which comprehensive examination, including radiographs, was performed and clinical findings were recorded. Participants also completed the Oral Health Impact Profile-49 (OHIP-49) and a 20-item visual analog scale (VAS) satisfaction questionnaire. Nonparametric statistical tests were used to compare OHIP-49 and VAS scores across age, sex, time since overdenture insertion, mandibular dental status, smoking status, maxillary mucosal health, and overdenture hygiene. RESULTS: For the 44 participants, 3 of 4 implants failed in 1 individual. The cumulative implant survival rate was 98% (97.7% patient level). No prosthetic failures (that is, overdenture replacement) occurred, indicating a 100% prosthesis survival rate. The mean ±standard deviation OHIP-49 severity score was 23.6 ±26.0, and the mean ±standard deviation total VAS score was 179.2 ±29.4. Increased age was associated with lower OHIP-49 severity score (P=.036), and participants with unhealthy oral mucosa or denture stomatitis demonstrated significantly higher OHIP-49 severity scores (P=.003). CONCLUSIONS: In this retrospective evaluation, unsplinted implant-retained maxillary overdenture therapy was associated with high implant and prosthetic survival, as well as high patient satisfaction and quality of life. Age, sex, maxillary mucosal health, and mandibular dental status resulted in significant differences with respect to oral health-related quality of life and patient satisfaction, indicating that this treatment option may be ideal for certain patients.

Internal fit of pressed and computer-aided design/computer-aided manufacturing ceramic crowns made from digital and conventional impressions.

STATEMENT OF PROBLEM: No studies have evaluated the internal adaptation of pressed and milled ceramic crowns made from digital impressions. PURPOSE: The purpose of this in vitro study was to evaluate the internal fit of pressed and milled ceramic crowns made from digital and conventional impressions. MATERIAL AND METHODS: Thirty polyvinyl siloxane (PVS) impressions and 30 Lava COS impressions made of a prepared dentoform tooth (master die) were fabricated. Thirty crowns were pressed in lithium disilicate (IPS e.max Press), and 30 crowns were milled from lithium disilicate blocks (IPS e.max CAD) (15/impression technique) with the E4D scanner and milling engine. The master die and the intaglio of the crowns were digitized with a 3-dimensional laser coordinate measurement machine. The digital master die and intaglio of each crown were merged. The distance between the die and the intaglio surface of the crown was measured at 3 standardized points. One-way ANOVA was used for statistical analysis (α=.05). RESULTS: One-way ANOVA revealed that the internal gap obtained from the Lava/press group (0.211 mm, ±SD 0.041) was significantly greater than that obtained from the other groups (P<.001), while no significant differences were found among PVS/press (0.111 mm ±SD 0.047), PVS/CAD/CAM (0.116 mm ±SD 0.02), and Lava/CAD/CAM (0.145 mm ±SD 0.024). CONCLUSIONS: The combination of the digital impression and pressed crown produced the least accurate internal fit.

3D and 2D marginal fit of pressed and CAD/CAM lithium disilicate crowns made from digital and conventional impressions.

PURPOSE: This in vitro study evaluated the 3D and 2D marginal fit of pressed and computer-aided-designed/computer-aided-manufactured (CAD/CAM) all-ceramic crowns made from digital and conventional impressions. MATERIALS AND METHODS: A dentoform tooth (#30) was prepared for an all-ceramic crown (master die). Thirty type IV definitive casts were made from 30 polyvinyl siloxane (PVS) impressions. Thirty resin models were produced from thirty Lava Chairside Oral Scanner impressions. Thirty crowns were pressed in lithium disilicate (IPS e.max Press; 15/impression technique). Thirty crowns were milled from lithium disilicate blocks (IPS e.max CAD; 15/impression technique) using the E4D scanner and milling engine. The master die and the intaglio of the crowns were digitized using a 3D laser coordinate measurement machine with accuracy of ±0.00898 mm. For each specimen a separate data set was created for the Qualify 2012 software. The digital master die and the digital intaglio of each crown were merged using best-fitting alignment. An area above the margin with 0.75 mm occlusal-gingival width circumferentially was defined. The 3D marginal fit of each specimen was an average of all 3D gap values on that area. For the 2D measurements, the marginal gap was measured at two standardized points (on the margin and at 0.75 mm above the margin), from standardized facial-lingual and mesial-distal digitized sections. One-way ANOVA with post hoc Tukey's honestly significant difference and two-way ANOVA tests were used, separately, for statistical analysis of the 3D and 2D marginal data (alpha = 0.05). RESULTS: One-way ANOVA revealed that both 3D and 2D mean marginal gap for group A: PVS impression/IPS e.max Press (0.048 mm ± 0.009 and 0.040 mm ± 0.009) were significantly smaller than those obtained from the other three groups (p < 0.0001), while no significant differences were found among groups B: PVS impression/IPS e.max CAD (0.088 mm ± 0.024 and 0.076 mm ± 0.023), C: digital impression/IPS e.max Press (0.089 mm ± 0.020 and 0.075 mm ± 0.015) and D: digital impression/IPS e.max CAD (0.084 mm ± 0.021 and 0.074 mm ± 0.026). The results of two-way ANOVA revealed a significant interaction between impression techniques and crown fabrication methods for both 3D and 2D measurements. CONCLUSIONS: The combination of PVS impression method and press fabrication technique produced the most accurate 3D and 2D marginal fits.

Clinical Applications of 3D-Printed Polymers in Dentistry: A Scoping Review.

PURPOSE: The aim of this scoping review is to categorize 3D-printing applications of polymeric materials into those where there is evidence to support their clinical application and to list the clinical applications that require a greater evidence base or further development before adoption. MATERIALS AND METHODS: An electronic search on PubMed, EMBASE, Scopus (Elsevier), and Cochrane Library databases was conducted, including articles written in English and published between January 2003 and September 2023. The search terms were: ((3D printing) OR (3-dimensional printing) OR (three dimensional printing) OR (additive manufacturing)) AND ((polymer) OR (resin)) AND (dent*). Case reports, in vitro, in situ, ex vivo, or clinical trials focused on applications of 3D printing with polymers in dentistry were included. Review articles, systematic reviews, and articles comparing material properties without investigation on clinical application and performance/accuracy were excluded. RESULTS: The search provided 3,070 titles, and 969 were duplicates and removed. A total of 2,101 records were screened during the screening phase, and 1,628 records were excluded based on title/abstract. In the eligibility phase, of the 473 full-text articles assessed for eligibility, 254 articles were excluded. During the inclusion phase, a total of 219 studies were included in qualitative synthesis. CONCLUSIONS: There is lack of clinical evidence for the use of 3D-printing technologies in dentistry. Current evidence, when investigating clinical outcomes only, would indicate non-inferiority of 3D-printed polymeric materials for applications including diagnostic models, temporary prostheses, custom trays, and positioning/surgical guides/stents.

Facially Driven Digital Workflow for Maxillary and Mandibular Milled Implant- Retained Overdentures Using Two Different Unsplinted Attachment Systems: Case Report.

Unsplinted attachment systems for implant overdentures offer various benefits for edentulous patients, including cost-effectiveness, enhanced cleansability, and less need for manual dexterity. This article describes a facially driven digital workflow for fabricating a maxillary implant overdenture retained by conometric-style attachments (Atlantis® Conus) with a palateless design opposing an implant overdenture retained by standard attachments (LOCATOR®). This procedure provides a predictable and accurate technique to digitally scan the master casts with wax rims for articulation and to guide the digital teeth design set-up for a predictable esthetic outcome. The removable prosthesis workflow involves virtual teeth set-up, a 3D-printed trial denture, a milled definitive prosthesis, and intraoral pick-up for both unsplinted attachment systems. The clinical and laboratory steps are described.