Biological interaction, esthetics, handling, and loss rate of temporary luting cements - a clinical single-blind randomized controlled trial.

OBJECTIVES: To evaluate three temporary luting cements in terms of their restoration loss rates, biological interactions, esthetic properties, and handling characteristics. MATERIALS AND METHODS: 75 adults requiring fixed prosthodontics voluntarily participated in a single-blind, randomized controlled trial. After preparation, temporary restorations were luted with a randomly selected temporary luting cement (either Provicol QM Plus (PQP), Bifix Temp (BT), or Provicol QM Aesthetic (PQA)). Clinical examinations were performed one to two weeks after cementation. The following criteria were evaluated: tooth vitality, percussion, hypersensitivity, gingival bleeding, odor formation, esthetics, cement handling, removability, cleanability, and retention loss. Antagonistic teeth served as controls. Statistical analysis was performed using the paired t-test, one-way ANOVA, Pearson's chi-square and Fisher's exact test, where appropriate. RESULTS: The overall loss rate of temporary restorations was 16.0%, showing no cement-specific differences. Postoperative hypersensitivity occurred in 8% of cases regardless of cement type. Esthetic impairment was reported by 31% of the PQP-fixed restorations, compared with 4.0% and 4.2% of the BT and PQA-bonded restorations. Cement application was reported to be easy in 100% of cases, excess removal in 88-96%, depending on the cement used. CONCLUSIONS: The choice of luting material affects the esthetic appearance of a temporary restoration and should be considered, particularly in restorations in esthetically demanding areas. No significant differences between the cements were identified regarding biocompatibility, handling, and loss rate. CLINICAL RELEVANCE: Translucent cements can help to reduce color interferences, resulting in a more appealing appearance of the temporary restoration.

Application of artificial intelligence in dental crown prosthesis: a scoping review.

BACKGROUND: In recent years, artificial intelligence (AI) has made remarkable advancements and achieved significant accomplishments across the entire field of dentistry. Notably, efforts to apply AI in prosthodontics are continually progressing. This scoping review aims to present the applications and performance of AI in dental crown prostheses and related topics. METHODS: We conducted a literature search of PubMed, Scopus, Web of Science, Google Scholar, and IEEE Xplore databases from January 2010 to January 2024. The included articles addressed the application of AI in various aspects of dental crown treatment, including fabrication, assessment, and prognosis. RESULTS: The initial electronic literature search yielded 393 records, which were reduced to 315 after eliminating duplicate references. The application of inclusion criteria led to analysis of 12 eligible publications in the qualitative review. The AI-based applications included in this review were related to detection of dental crown finish line, evaluation of AI-based color matching, evaluation of crown preparation, evaluation of dental crown designed by AI, identification of a dental crown in an intraoral photo, and prediction of debonding probability. CONCLUSIONS: AI has the potential to increase efficiency in processes such as fabricating and evaluating dental crowns, with a high level of accuracy reported in most of the analyzed studies. However, a significant number of studies focused on designing crowns using AI-based software, and these studies had a small number of patients and did not always present their algorithms. Standardized protocols for reporting and evaluating AI studies are needed to increase the evidence and effectiveness.

Fracture resistance, marginal and internal adaptation of innovative 3D-printed graded structure crown using a 3D jet printing technology.

PURPOSE: This in vitro study aimed to create a graded structured dental crown using 3D printing technology and investigate the fracture resistance and the adaptation of this new design. MATERIALS AND METHODS: A dental crown with a uniform thickness of 1.5 mm was designed, and the exported stereolithography file (STL) was used to manufacture 30 crowns in three groups (n = 10), solid (SC), bilayer (BL), and multilayer (ML) crowns using  3D jet printing technology. Marginal and internal gaps were measured using the silicone replica technique. Crowns were then luted to a resin die using a temporary luting agent and the fracture resistance was measured using a universal testing machine. One-way ANOVA and Tukey post hoc tests were used to compare the fracture resistance and the adaptation of crowns at a significance level of 0.05. RESULTS: Mean marginal and internal gap of the ML group were 80 and 82 mm, respectively; which were significantly (p < 0.05) smaller than BL (203 and 183 mm) and SC (318 and 221 mm) groups. The SC group showed the highest mean load at fracture (2330 N) which was significantly (p < 0.05) higher than the BL (1716 N) and ML (1516 N) groups. CONCLUSION: 3D jet printing technology provides an opportunity to manufacture crowns in a graded structure with various mechanical properties. This study provided an example of graded structured crowns and presented their fracture resistance. SC group had the highest fracture resistance; however, ML had the best marginal and internal adaptation.

Systematic review evaluating the influence of the prosthetic material and prosthetic design on the clinical outcomes of implant-supported multi-unit fixed dental prosthesis in the posterior area.

OBJECTIVE: The objectives of the study were to assess the survival, failure, and technical complication rates of implant-supported fixed dental prosthesis (iFDPs) with pontic or splinted crown (iSp C) designs in the posterior area and compare the influence of prosthetic materials and prosthetic design on the outcomes. METHODS: Electronic and manual searches were performed to identify randomized-, prospective-, and retrospective clinical trials with follow-up time of ≥12 months, evaluating the clinical outcomes of posterior iFDPs with pontic or iSp Cs. Survival and complication rates were analyzed using robust Poisson's regression models. RESULTS: Thirty-two studies reporting on 42 study arms were included in the present systematic review. The meta-analysis of the included studies indicated estimated 3-year survival rates of 98.3% (95%CI: 95.6-99.3%) for porcelain-fused-to-metal (PFM) iFDPs, 97.5% (95%CI: 95.5-98.7%) for veneered zirconia (Zr) iFDPs with pontic, 98.9% (95%CI: 96.8-99.6%) for monolithic or micro-veneered zirconia iFDPs with pontic, and 97.0% (95%CI: 84.8-99.9%) for lithium disilicate iFDPs with pontics. The survival rates for different material combination showed no statistically significant differences. Veneered restorations, overall, showed significantly (p < .01) higher ceramic fracture and chipping rates compared with monolithic restorations. Furthermore, there was no significant difference in survival rates (98.3% [95%CI: 95.6-99.3%] vs. 99.1% [95%CI: 97.6-99.7%]) and overall complication rates between PFM iFDPs with pontic and PFM iSp Cs. CONCLUSIONS: Based on the data identified by this systematic review, PFM, veneered Zr, and monolithic Zr iFDPs with pontic and iSp Cs showed similarly high short-term survival rates in the posterior area. Veneered restorations exhibit ceramic chipping more often than monolithic restorations, with the highest fracture rate reported for veneered Zr iFDPs.

Influence of geometric dimensions on early failures of adhesively retained composite resin core build-ups.

OBJECTIVE: To determine the influence of the geometric dimensions of core build-ups on early core build-up failure, that is, loss before definitive prosthesis cementation. MATERIALS AND METHODS: Adhesive core build-ups of exclusively vital teeth in 114 participants were evaluated (n materials: 40 Rebilda DC, 38 Multicore Flow, 36 Clearfil DC Core; n teeth: 8 incisors, 54 premolars, 52 molars). Impressions of the abutment teeth were made (1) after removal of insufficient restorations/caries and (2) after core build-up and preparation for a fixed prosthesis. Digitized model surfaces of both situations were aligned (Geomagic Design X) and core build-up volume (VCBU ), remaining hard tissue volume (VAbut ), and size of the adhesive surface (Aadh ) were assessed. The derived measure dCBU  = VCBU /Aadh can be interpreted as mean arithmetic core build-up thickness. Associations between participant or core build-up design characteristics and the occurrence of early failures were statistically evaluated (SPSS v27, α = 0.05). RESULTS: A total of six (5.3%) core build-up failures were registered. Higher participant age, greater core build-up volume VCBU and greater arithmetic uniform thickness dCBU were associated with a greater incidence of failure in bivariate and univariate, however, not in multivariate statistics. CONCLUSIONS: Core build-up volume and thickness were associated with early success or failure. CLINICAL SIGNIFICANCE: In the case of voluminous/thick core build-ups in relation to the adhesive surface, additional measures, such as the preparation of retentive elements to increase the bonding area, might be considered to reduce the risk of early core build-up failure.

Potential of intraoral optical scanning to evaluate motor skills' improvement for tooth preparation: A prospective cohort study.

INTRODUCTION: This prospective cohort study investigated the potential of digital assessment using intraoral scanning (IOS) combined with software analysis (prepCheck) to evaluate the outcome of repetitive tooth preparation and its influence on the acquisition of motor skills in dental students. MATERIALS AND METHODS: Twenty-six students completed 177 full-crown preparations of the same tooth in six practice sessions followed by a final examination. Preparations were assessed digitally using prepCheck and conventionally by calibrated faculty instructors. In addition, students assessed their own performance and this was compared with the instructors' assessments. RESULTS: Conventional assessment showed that students preparations improved over time, with 43.5% of students receiving score 2 (highest grade) at the fifth practice session. With the prepCheck assessment, statistically significant improvements indicated by an enlarged area within the tolerance range set at 0.2 mm were found between the first and the second practice session (7.5% improvement; 95% CI: 2.2%, 12.7%, p = 0.006), and between the first run and the final exam preparation (6.7%; 95% CI: 1.7%, 12.5%, p = 0.011). Agreement between instructor/student assessments was best immediately after students received visual feedback using prepCheck (76% agreement; Spearman's rho 0.78). CONCLUSION: These data indicate that IOS technology was useful for student's self-evaluation by visual feedback.

Additively Manufactured Dental Crown with Color Gradient and Graded Structure: A Technique Report.

To assess the feasibility of manufacturing a dental crown with internal color gradient and graded structure design using additive manufacturing technology, a mandibular first molar was prepared and a monolayer dental crown with 1.5 mm uniform thickness was designed in a dental software (STLC1 ). The monolayer crown design was sliced into multiple layers of 0.1 mm thickness and a design for a multilayer crown was obtained (STLC2 ). A multilayer crown was manufactured with gradient color and graded structure using a material jetting printer. Different materials with different colors and properties were used and mixed in different ratios during manufacturing to achieve the prospected design. The feasibility of manufacturing such a crown was reported. This report confirms that multilayer dental crowns with internal gradient color and graded structure are possible when using a multimaterial jetting printer.

Functional, compositional, and regulatory analyses of imported and non-imported single dental crowns.

The aims of the study were to investigate functional and esthetic properties, the composition of the alloy, and the content of hazardous elements of single dental crowns with metal skeleton and fired porcelain. Epoxy models made from full mouth impressions taken of a patient with a crown preparation of the right maxillary first permanent molar were used for production of identical polyether impressions, which were distributed to dentists in Norway. The dentists sent the impressions to their regular dental laboratories. All 55 crowns collected were anonymized and examined. Of the crowns received, 35 were made in Norway, 12 were imported, and 8 were of unknown origin. The evaluation of functional properties revealed that 50% of the Norwegian, 42% of the imported, and 25% of the unknown-origin crowns were considered unacceptable. The composition of the alloy was not in accordance with that stated by the manufacturer for 17%, 13% and 20% of the crowns, where this information was provided. The lead content of the alloy exceeded the limit set by the ISO 22674: 2016 for 18% of the crowns in total. The statement that shall follow the work according to EU-regulations was not complete for approximately 75% of the works received.

Changes in masticatory laterality 3 months after treatment with unilateral implant-supported fixed partial prosthesis.

OBJECTIVE: This study assessed changes in masticatory laterality in patients with unilateral posterior missing teeth 3 months after treatment with an implant-supported fixed partial prosthesis (ISFPP). METHODS: Thirty patients with unilateral posterior missing teeth participated in this prospective study. They were treated with one-, two- or three-unit ISFPPs. The control group comprised 10 healthy individuals with complete natural dentition. Each participant performed masticatory assays at baseline and at 3-month follow-up, chewing pieces of silicon inside a latex bag. Masticatory laterality was determined using three different methods: assessment of the first chewing cycle, of all cycles and application of a visual analogue scale. Data were compared using the Kruskal-Wallis or the Mann-Whitney U test as appropriate. RESULTS: Three months after treatment, a significant change in the asymmetry index towards the treated side and a significant reduction in the Unilateral Chewing Index were observed in the ISFPP group. No significant differences in masticatory laterality between groups were detected at 3-month follow-up, regardless of the method assessed. CONCLUSION: Treatment with ISFPPs alters the masticatory laterality, moving it to the treated side and increasing the degree of bilateral chewing in patients with unilateral posterior missing teeth.

Do implant-supported fixed partial prostheses improve masticatory performance in patients with unilateral posterior missing teeth?

OBJECTIVES: The purpose of this study was to determine the improvement in masticatory performance and satisfaction with chewing ability in partially edentulous patients after treatment with an implant-supported fixed partial prosthesis (ISFPP). MATERIAL AND METHODS: This prospective study included 30 patients (mean age 59 years; 17 women) with unilateral posterior missing teeth treated with one-, two- or three-unit ISFPPs and 10 healthy individuals (mean age 36 years; 8 women) with complete natural dentition to establish the normal levels of mastication. Three variables were determined at baseline and at 3-months' follow-up in all participants: masticatory performance according to the median particle size (MPS) during freestyle mastication and unilateral mastication on each side, and satisfaction with chewing ability using a visual analog scale. Paired samples t test and Kruskal-Wallis test were used for intra-group and inter-group comparisons. RESULTS: The MPS following freestyle mastication decreased significantly at 3 months in both groups. Significant reductions of 21%, 30%, and 42% in the MPS were obtained from unilateral mastication on the treated side after treatment with 1, 2, or 3 restorative units, respectively. Three months after ISFPP, satisfaction with chewing ability improved by 40% in the treatment group. CONCLUSIONS: Freestyle masticatory performance may improve slightly within three months of treatment with an ISFPP and may be similar to that of subjects with complete natural dentition. Patients may obtain a 21%-38% improvement in unilateral mastication on the treated side and a 26%-54% improvement in satisfaction with chewing ability.

Accuracy of crowns based on digital intraoral scanning compared to conventional impression-a split-mouth randomised clinical study.

OBJECTIVES: The aim of this prospective in vivo study was to evaluate the accuracy of the marginal and internal fit of crowns based on conventional impression (CI) or intraoral scan (IOS) in a randomised, split-mouth set-up. MATERIALS AND METHODS: Nineteen patients needing full coverage crowns, fitting a split-mouth design, were provided with two lithium disilicate crowns: one based on a CI and one based on an IOS. The marginal and internal accuracy of the crowns were assessed with the replica technique and clinically using a modified California Dental Association (CDA) quality evaluation system. RESULTS: At the preparation margin, the median gap was 60 µm for IOS and 78 µm for CI. For the other points, the median gap ranged from 91 to 159 µm for IOS and 109 to 181 µm for CI. The accuracy of the IOS was statistically significantly better at all point except at the cusp tip. All crowns where rated R or S at both the 6- and 12-month follow-up appointments. The results for the clinical evaluation with CDA for marginal integrity showed no statistically significant difference between the two impression methods at both the 6- and 12-month evaluations. CONCLUSIONS: Crowns based on IOS show statistically significantly better marginal and internal adaptation before cementation compared to conventional impression. However, the clinical evaluation showed similar marginal adaptation. CLINICAL RELEVANCE: Crowns based on a fully digital workflow can provide clinically acceptable marginal adaptation, comparable to crowns based on CI.

Microstructural and Mechanical Characterization of CAD/CAM Materials for Monolithic Dental Restorations.

PURPOSE: To determine and compare the microstructure, flexural strength, flexural modulus, fracture strength, and microhardness of four types of computer-aided design/computer-aided manufacturing (CAD/CAM) materials for monolithic dental restorations. MATERIALS AND METHODS: A lithium disilicate (LD; IPS e.max CAD), a zirconia-reinforced lithium silicate (ZLS; VITA Suprinity), a hybrid high-performance polymer (HPP) composite resin (GC Cerasmart), and a hybrid polymer-infiltrated ceramic network (PICN) material (VITA Enamic) were used to manufacture monolithic ceramic posterior crowns (n = 10) that were adhesively cemented on resin-based composite dies and loaded until fracture. In addition, 40 rectangular bars (n = 10) were milled and polished for three-point flexural strength testing. Microhardness (Vickers indentation), as well as quantitative (energy dispersive spectroscopy) and qualitative (scanning electron microscopy) structural analysis were conducted on fracture surfaces. Data were analyzed by one-way ANOVA and Tukey HSD post-hoc test (p = 0.05). RESULTS: Mechanical testing results showed that the material type has a significant effect on the fracture strength (p < 0.0001) of the monolithic crowns with ZLS and LD presenting significantly higher fracture strength than the PICN and HPP hybrid materials. LD showed the highest flexural strength (p < 0.0001) followed by ZLS, HPP, and PICN, respectively. The lowest flexural modulus and hardness were presented by HPP whereas ZLS had the highest flexural modulus and hardness. The LD presented the highest modulus of resilience and the PICN the lowest. CONCLUSIONS: All CAD/CAM crown materials exhibited high values of fracture and flexural resistance, making them suitable materials for posterior full-crown restorations. Glass-ceramics suffered more from catastrophic and nonreparable fracture patterns, whereas minimal chipping and type II fracture patterns were more common in hybrid materials. The combination of more flexibility, less stiffness, and increased softness with satisfactory flexural and fracture strength values observed in PICN and HPP makes these two hybrid materials suitable choices for chairside monolithic crown fabrication.

Papilla-Crown Height Dimensions around Zirconium Dioxide Implants in the Esthetic Area: A 3-Year Follow-Up Study.

PURPOSE: Soft tissue interactions with ceramic dental implants have previously been shown to have favorable esthetic outcomes. This study aimed to evaluate the papilla-crown proportion around zirconia implants in a 3-year follow-up study and the correlation between the gingival biotype and changes in papillary height. MATERIALS AND METHODS: This was a prospective study of 39 patients with 40 single-gap implants (Straumann PURE Ceramic ZLA Implant). The papilla-crown proportion was assessed after 3 months, 1 year, and 3 years. In addition, correlations between the peri-implant biotypes and changes in papillary heights were evaluated. RESULTS: The papilla-crown proportion improved from 35.5% after 3 months to 41.7% after 3 years. The gingival biotype was correlated very weakly to papilla height alterations. Significant papillary fill was observed in the interdental space between 3 months and 3 years (p < 0.001). CONCLUSIONS: An ideal papilla-crown proportion of 40% around single implants was observed after 3 years. A thin or thick gingival biotype showed a very weak correlation with soft tissue alterations.

Analysis of Vertical Misfit of Crowns Fabricated with CAD/CAM Technology using Two Scanning Techniques: Direct and Indirect.

AIM: The study evaluated the marginal vertical misfit of feldspathic ceramic crowns fabricated by the computer-aided design (CAD)/computer-aided manufacturing (CAM) technology and compared the two methods of scanning techniques: direct digital impression and indirect digital impression. MATERIALS AND METHODS: The titanium specimens were divided into two groups: scanning with the direct digital impression (DDI) at the milled prosthetic abutment level and indirect digital impression (IDI) at the cast model and after milled feldspathic ceramics blocks. Vertical marginal misfit was analyzed. The t-test was used for the analysis of the comparison factor between the groups and the one-way analysis of variance (ANOVA) test, and post hoc Tukey test was used to compare the variance of crown analysis regions within the group. A significance level of 5% was considered for the analyses. RESULTS: There was no significant difference in vertical marginal misfit between the groups of DDI and IDI (p = 0.345). In relation to each region measured within the studied groups, it was observed the similarity between the six regions analyzed in the DDI group (p >0.05) and IDI group, a significant difference between two areas. CONCLUSION: The vertical marginal adaptation was similar between digital scanning methods. Based on the data evaluated, vertical marginal adaptation indices were within acceptable clinical standards. CLINICAL SIGNIFICANCE: The direct digital scanning in unit bodies was reliable, pointing that the coating of titanium dioxide in the titanium abutment did not negatively influence the vertical marginal adaptation of the feldspathic ceramic crowns.

Internal fit of three-unit fixed dental prostheses produced by computer-aided design/computer-aided manufacturing and the lost-wax metal casting technique assessed using the triple-scan protocol.

Suboptimal adaptation of fixed dental prostheses (FDPs) can lead to technical and biological complications. It is unclear if the computer-aided design/computer-aided manufacturing (CAD/CAM) technique improves adaptation of FDPs compared with FDPs made using the lost-wax and metal casting technique. Three-unit FDPs were manufactured by CAD/CAM based on digital impression of a typodont model. The FDPs were made from one of five materials: pre-sintered zirconium dioxide; hot isostatic pressed zirconium dioxide; lithium disilicate glass-ceramic; milled cobalt-chromium; and laser-sintered cobalt-chromium. The FDPs made using the lost-wax and metal casting technique were used as reference. The fit of the FDPs was analysed using the triple-scan method. The fit was evaluated for both single abutments and three-unit FDPs. The average cement space varied between 50 µm and 300 µm. Insignificant differences in internal fit were observed between the CAD/CAM-manufactured FDPs, and none of the FPDs had cement spaces that were statistically significantly different from those of the reference FDP. For all FDPs, the cement space at a marginal band 0.5-1.0 mm from the preparation margin was less than 100 µm. The milled cobalt-chromium FDP had the closest fit. The cement space of FDPs produced using the CAD/CAM technique was similar to that of FDPs produced using the conventional lost-wax and metal casting technique.

Fracture resistance of zirconia-based all-ceramic crowns after bur adjustment.

Intra-oral grinding is often required to optimize occlusion of all-ceramic restorations. The effect of burs of different grit size on the fracture resistance of veneered zirconia crowns was investigated in this study. Forty-eight standardized zirconia copings were produced. The ceramic veneer was designed with a positive ellipsoidal defect on the palatal aspect of the crowns. To simulate adjustment of dental restorations by burs, this palatal defect was removed by use of three different diamond-coated burs with grit sizes 46, 107, or 151 µm (fine, medium, or coarse, respectively). Each different grit size of bur was used to grind 16 crowns. All crowns were then polished and surface roughness was measured. Half of the specimens underwent thermomechanical aging (10,000 thermocycles between 6.5°C and 60°C) and 1.2 million cycles of chewing simulation (F = 108 N). A linear regression model was computed to test the effect of aging and grinding grit size at a level of significance of α = 0.05. Fracture loads increased with decreasing grit size. Grit size and aging had a significant effect on the fracture resistance of the crowns. Use of fine and coarse burs for intra-oral adjustments resulted in different fracture resistance of veneered zirconia crowns. Coarse burs should be avoided in the final stage of grinding before polishing.

Review of techniques for the intact removal of a permanently cemented restoration.

The safest and least traumatic means of removing a cemented restoration is to cut a slot and pry the crown or retainer loose, sacrificing the restoration. However, various techniques and instruments for intact removal of permanently cemented cast restorations have been described in the literature. This literature review explores conservative and semiconservative techniques that are useful for preserving permanently cemented restorations during removal. Richwil resin, ultrasonic energy, and crown tractors can be considered preferred methods for removal of temporarily cemented restorations. Patients should be informed regarding the risks and benefits before removal of a cemented restoration.

Time-efficiency analysis of the treatment with monolithic implant crowns in a digital workflow: a randomized controlled trial.

OBJECTIVES: The aim of the randomized controlled trial was to analyze time-efficiency of a treatment with implant crowns made of monolithic lithium disilicate (LS2) plus titanium base vs. porcelain fuse to zirconium dioxide (ZrO2 ) in a digital workflow. MATERIALS AND METHODS: Twenty study participants were included for single-tooth replacement in premolar and molar sites. Baseline was the start of the prosthetic treatment. All patients received transocclusal screw-retained implant reconstructions on a soft tissue level-type implant. The 3D implant position was captured with intraoral optical scanning (IOS). After randomization, ten patients were restored with CAD-/CAM-produced monolithic LS2-crowns bonded to prefabricated titanium abutments without any physical models (test), and ten patients with CAD-/CAM-fabricated ZrO2 -suprastructures and hand-layered ceramic veneering with milled master models (control). Every single clinical and laboratory work step was timed in minutes and then analyzed for time-efficiency with Wilcoxon Rank Sum Tests. Direct costs were assessed for laboratory fees for first line production in Swiss Francs (CHF). RESULTS: Two clinical appointments were necessary for IOS and seating of all implant crowns. The mean total production time, as the sum of clinical plus laboratory work steps, was significantly different, resulting in 75.3 min (SD ± 2.1) for test and 156.6 min (SD ± 4.6) for control [P = 0.0001]. Analysis for clinical treatment sessions showed a significantly shorter mean chair time for the complete digital workflow of 20.8 min (SD ± 0.3) compared to 24.1 min (SD ± 1.1) [P = 0.001]. Even more obvious were the results for the mean laboratory work time with a significant reduction of 54.5 min (SD ± 4.9) vs. 132.5 min (SD ± 8.7), respectively [P = 0.0001]. CONCLUSION: The test workflow was more time-efficient than the controls for implant-supported crowns; notably, laboratory fabrication steps could be effectively shortened with the digital process of monolithic LS2 plus titanium base resulting in more than 30% reduced overall treatment costs.

Digital vs. conventional implant prosthetic workflows: a cost/time analysis.

OBJECTIVES: The aim of this prospective cohort trial was to perform a cost/time analysis for implant-supported single-unit reconstructions in the digital workflow compared to the conventional pathway. MATERIALS AND METHODS: A total of 20 patients were included for rehabilitation with 2 × 20 implant crowns in a crossover study design and treated consecutively each with customized titanium abutments plus CAD/CAM-zirconia-suprastructures (test: digital) and with standardized titanium abutments plus PFM-crowns (control conventional). Starting with prosthetic treatment, analysis was estimated for clinical and laboratory work steps including measure of costs in Swiss Francs (CHF), productivity rates and cost minimization for first-line therapy. Statistical calculations were performed with Wilcoxon signed-rank test. RESULTS: Both protocols worked successfully for all test and control reconstructions. Direct treatment costs were significantly lower for the digital workflow 1815.35 CHF compared to the conventional pathway 2119.65 CHF [P = 0.0004]. For subprocess evaluation, total laboratory costs were calculated as 941.95 CHF for the test group and 1245.65 CHF for the control group, respectively [P = 0.003]. The clinical dental productivity rate amounted to 29.64 CHF/min (digital) and 24.37 CHF/min (conventional) [P = 0.002]. Overall, cost minimization analysis exhibited an 18% cost reduction within the digital process. CONCLUSION: The digital workflow was more efficient than the established conventional pathway for implant-supported crowns in this investigation.

Complete digital workflow for the production of implant-supported single-unit monolithic crowns.

OBJECTIVES: The aim of this case series was to introduce a complete digital workflow for the production of monolithic implant crowns. MATERIAL AND METHODS: Six patients were treated with implant-supported crowns made of resin nano ceramic (RNC). Starting with an intraoral optical scan (IOS), and following a CAD/CAM process, the monolithic crowns were bonded either to a novel prefabricated titanium abutment base (group A) or to a CAD/CAM-generated individualized titanium abutment (group B) in premolar or molar sites on a soft tissue level dental implant. Economic analyses included clinical and laboratory steps. An esthetic evaluation was performed to compare the two abutment-crown combinations. RESULTS: None of the digitally constructed RNC crowns required any clinical adaptation. Overall mean work time calculations revealed obvious differences for group A (65.3 min) compared with group B (86.5 min). Esthetic analysis demonstrated a more favorable outcome for the prefabricated bonding bases. CONCLUSIONS: Prefabricated or individualized abutments on monolithic RNC crowns using CAD/CAM technology in a model-free workflow seem to provide a feasible and streamlined treatment approach for single-edentulous space rehabilitation in the posterior region. However, RNC as full-contour material has to be considered experimental, and further large-scale clinical investigations with long-term follow-up observation are necessary.