Mechanical performance of patient-specific prefabricated temporary shell versus laboratory-fabricated CAD/CAM provisional implant-supported single-tooth restorations: A laboratory study.

OBJECTIVE: To evaluate the mechanical performance of patient-specific prefabricated temporary shell versus laboratory-fabricated CAD/CAM provisional restorations on titanium temporary abutments, with and without thermo-mechanical ageing. MATERIALS AND METHODS: Implants with a conical connection were divided into four groups (n = 24) and restored with temporary shell or laboratory-fabricated central or lateral incisor PMMA restorations that were relined or bonded on titanium temporary abutments. The diameter of the central and lateral incisor groups' implants was regular (ϕ 4.3 mm) or narrow (ϕ 3.5 mm), respectively. Half of each group's specimens were subjected to ageing, simultaneous thermocycling (5-55°C) and chewing simulation (120,000 cycles, 50 N, 1.7 Hz) resulting in eight groups in total (n = 12). The aged specimens were evaluated with optical microscopy, and survival and complication rates were determined according to modified USPHS criteria. The non-aged specimens and those that had survived ageing were loaded until failure, whereupon bending moments were calculated. RESULTS: Survival rates after ageing were 100% for all groups. Apart from wear facets (ϕ 2-3 mm) on the palatal restoration surface, no complications were observed. The mean fracture load and bending moments ranged between 597.6-847.1 N and 433.3-550.6 Ncm, respectively, with no significant differences between the eight groups (p = .25; p = .20). CONCLUSIONS: As patient-specific temporary shell central and lateral incisor provisional implant-supported restorations are mechanically stable enough to withstand clinical bite forces, even after thermo-mechanical ageing, they may serve as an alternative to laboratory-fabricated provisional restorations.

Digital versus conventional surgical guide fabrication: A randomized crossover study on operator preference, difficulty, effectiveness, and operating time.

AIM: If surgical guide fabrication is introduced in a dental education program, a digital and conventional workflow can be used. This study evaluated operator preference, perceived difficulty and effectiveness and operating time of both fabrication methods. MATERIALS AND METHODS: Forty participants in a university setting (students, n = 20; dentists, n = 20) with varying levels of dental experience, but no experience in surgical guide fabrication, were randomly assigned to consecutively fabricate surgical guides on a standardized training model, with either the digital or conventional workflow first. The operating time was measured, and operator preference and the perception of difficulty and effectiveness were assessed with a questionnaire. T tests were used for statistical analysis (α = .05). RESULT: Of the students, 95% preferred the digital workflow and of the dentists 70%. The perceived difficulty of the digital workflow was significantly lower than the conventional workflow in the student group. Both groups perceived the digital workflow to be more effective. The mean operating time (mm:ss) amounted 12:34 ± 2:24 (students) and 18:07 ± 6:03 (dentists) for the digital, and 22:20 ± 3:59 (students) and 20:16 ± 4:03 (dentists) for the conventional workflow. CONCLUSION: Both students and dentists prefer the digital workflow for surgical guide fabrication. Students perceive the digital workflow as less difficult and more effective than the conventional workflow. The operating time for surgical guide fabrication is shorter with a digital workflow. This study indicates that digital fabrication techniques for surgical guides are preferred to be incorporated into the dental curriculum to teach students about treatment planning in implant dentistry.

Dental implant treatment for two adjacent missing teeth in the esthetic region: A systematic review and 10-year results of a prospective comparative pilot study.

OBJECTIVES: The aim of the systematic review was to compare studies on implant-supported two-unit cantilever crowns with two adjacent implant-supported crowns in the anterior region. The second aim was to assess in a 10-year prospective comparative pilot study, hard and soft peri-implant tissue changes in patients with a missing central and adjacent lateral upper incisor, treated with either an implant-supported two-unit cantilever crown or two single implant-supported crowns. MATERIALS AND METHODS: Medline, Embase, and the Cochrane Central Register of Controlled Trials were searched (last search March 1, 2023). Inclusion criteria were studies reporting outcomes of two missing adjacent teeth in the esthetic region and treated with a single implant-supported two-unit cantilever fixed dental prosthesis, or with two solitary implant-supported crowns. Outcome measures assessed included implant survival (primary), changes in marginal bone and gingiva level, restoration survival, subjective and objective esthetic scores, papilla volume, mid-facial marginal mucosa level, probing depth, bleeding on probing, and biological and technical complications with ≥1-year follow-up. In addition, in a 10-year pilot study, the same outcome measures were assessed of five patients with a single implant-supported two-unit cantilever crown and compared with five patients with two adjacent single implant-supported crowns in the esthetic zone. RESULTS: Nine articles with 11 study groups were found eligible for data extraction. Meta-analyses of implant survival rates were 96.9% (mean follow-up 3.4 ± 1.4 years) for the implant-cantilever treatment and 97.6% (mean follow-up 3.0 ± 1.8 years) for the adjacent implants treatment (p = .79). In the 10-year comparative pilot study, no clinically relevant changes in hard and soft peri-implant tissue levels occurred in both groups. Patient satisfaction was also high in both groups. CONCLUSION: Single implant-supported two-unit crowns can be a viable alternative to the placement of two adjacent single implant crowns in the esthetic zone.

Three-unit fixed dental prostheses supported by either two abutment implants or two abutment teeth: A comparative retrospective cohort study.

OBJECTIVES: In general, similar restorative constructions are made on natural teeth and on dental implants. The assumption is made that implants and their restoration perform the same as natural roots and their prosthetic restoration. Evaluating cohorts of three-unit bridges on teeth and on implants, this retrospective clinical study aimed to compare implants and teeth as supporting units, including the reconstructions, in terms of survival, success, clinical, radiographic, and patient-reported outcomes. MATERIAL AND METHODS: From an 8-year period, all patients treated with a posterior three-unit fixed reconstruction on either implants or teeth, with a follow-up of at least 2 years, were identified. For each implant-supported reconstruction, a comparable tooth-supported reconstruction was selected, based on the length of follow-up, the material of the reconstruction, and the location in either the maxilla or mandible. RESULTS: For the Implant-group, 24 patients could be matched with 24 best matching patients with tooth-supported fixed dental prostheses (FPDs). Supporting implants and implant-supported reconstructions were all in function with a mean follow-up of 52 ± 23 months. Two tooth-supported reconstructions had been replaced (91.7% survival) (mean follow-up: 52 ± 19 months). Radiographic bone levels and soft tissue conditions were favorable in both groups with minor differences. There was no significant difference in overall patient satisfaction. The modified USPHS-score revealed an 87.5% overall success in the Implant-group and 91.7% in the Tooth-group. CONCLUSIONS: Implant-supported three-unit FDPs are a reliable treatment option with survival and success rates not significantly different from the results of tooth-supported three-unit FDPs.

Full-zirconia single-tooth molar implant-supported restorations with angulated screw channel abutments: A 1-year prospective case series study.

BACKGROUND: Implant-supported restorations in the posterior region are subjected to various complications that could be prevented by changing either the design or the material. PURPOSE: The aim of this prospective case series study was to evaluate full-zirconia implant-supported restorations with angulated screw channel abutments in the molar region of the maxilla and mandible and their effect on hard and soft peri-implant tissues, during a 1-year follow-up period. MATERIALS AND METHODS: Thirty consecutive patients with a single missing molar, sufficient bone height, and implant site free of infection were included. Each patient was to receive a parallel-walled implant with conical connection according to a two-staged surgical protocol. After 3 months, a full-contour screw-retained zirconia restoration with angulated screw channel abutment was provided. Clinical and radiographic examinations were performed 1 and 12 months after placement of the restoration. Patients' satisfaction was scored prior to treatment and after 12 months with the restoration in function. Primary outcome measure was success of the restoration. RESULTS: All patients could be evaluated after 12 months. Success of the restorations was 100%. From loading to the 12-month follow-up, the mean marginal bone loss was 0.16 mm (SD: 0.26). Mean scores for plaque, calculus, peri-implant mucosa, bleeding, and pocket probing depth were low, depicting healthy peri-implant conditions. Patients' satisfaction was high and had improved after treatment. CONCLUSION: Full-contour zirconia implant-supported restorations with angulated screw channel abutments in the molar region have an excellent clinical performance after 1 year of function.

A systematic review of ceramic inlays in posterior teeth: an update.

PURPOSE: Ceramic materials, first introduced in restorative dentistry in the late 18th century, offer a wide range of possibilities and exhibit esthetic properties. The last systematic reviews on the subject of ceramic inlays were published in 2003. All articles published up to 2001 were surveyed regarding the longevity, esthetic qualities, and postoperative discomfort associated with the use of ceramic inlays compared to other restorative materials. The present review aimed to establish the current state of the art. MATERIALS AND METHODS: Using methods identical to those of previous reviews, the literature from 2001 up to and including 2009 was assessed. The scientific and methodologic qualities of all articles describing the use of ceramic inlays were established. Articles comparing the results of ceramic inlays to other types of inlays were then used to answer the hypotheses that there were no differences in longevity, postoperative sensitivity, or color match. RESULTS: Three articles comparing the results of ceramic to other materials were analyzed further. No new reliable evidence was found to update the answer to the hypothesis that there was no difference in longevity, at least in the first year postoperative. The evidence found regarding postoperative discomfort backs the previous conclusion that there was no difference. New evidence found on color matching suggests that there is no significant difference in color match over assessment periods of up to 57 months. CONCLUSION: Current ceramic materials in inlay restorations seem to perform as well as other restorative options for selected properties during the first years after placement.