Computer-aided Design/computer-assisted Manufacture Research Articles

Digital workflow for prosthetic management of malpositioned implant in an adolescent patient: A 20-year follow-up.

Dental implants placed in adolescent patients pose a challenge to restore and maintain an esthetic outcome over longer period of follow-up. Maxillomandibular changes throughout adulthood may lead to complications such as implant infraocclusion and interproximal contact loss. This case report describes an alternate prosthetic treatment strategy for maxillary single implant placed in an adolescent patient in the esthetic zone with inappropriate implant axis and screw hole placement. With temporary restorations, the gingiva and soft tissues were shaped to imitate the emerging profile of the contralateral side. A zirconia screw-retained abutment was customized as a copy-mirror from the contralateral prepared tooth to mimic the exact shape and to avoid labiolingual over contour by computer-aided design/computer-assisted manufacture (CAD/CAM). The porcelain laminate veneer was bonded to the zirconia abutment. Porcelain adhesive approach was used instead of traditional principles of retention and resistance form of the abutment. A functional and esthetic outcome was achieved and maintained, while a minimally invasive procedure was implemented to use the malplaced implant instead of explanting it. The present report illustrates the prosthetic management of a malpositioned dental implant placed 20 years ago, utilizing a minimally invasive digital protocol.

Comparison of the Passivity between CAD/CAM Implant Frameworks and Three Different Conventional Techniques Before and After Applying Veneering Porcelain

Background: The passivity of the fit may be at risk during the casting as well as the firing of the veneering ceramic. In this study, the comparison of the passivity between computer-aided design/computer-assisted manufacturing (CAD/CAM) implant frameworks and three different conventional techniques before and after applying veneering porcelain was investigated. Methods: In this laboratory cross-sectional study, four groups (n=6) of 3-unit screw-retained implant-supported denture prostheses (ISDPs) were fabricated on a master model with 2 implants. The study groups were as follows: conventional casting with Ni-Cr alloy (group 1), casting with Ni-Cr alloy followed by sectioning and soldering the samples (group 2), double casting with Ni-Cr framework (group 3), and using CAD/CAM-fabricated framework (group 4). All frameworks received porcelain veneer. The one-screw test was performed before and after veneering to measure the vertical misfit at the abutment-framework interface using a stereomicroscope. The mean vertical misfit values were determined at the buccal, lingual, and proximal aspects. The data were analyzed using the Kruskal-Wallis and post hoc tests (α=0.05). Results: The accuracy of the fit varied significantly before and after veneering among the study groups (P<0.001). Frameworks prepared with CAD/CAM showed lower mean marginal misfit values compared to the other fabrication methods (P<0.001). Conclusions: Firing the veneering porcelain attached to a screw-retained ISDP may have an adverse effect on the accuracy of the fit. Soft non-pre-sintered CAD/CAM frameworks had better passivity compared to other three conventional methods applied.

The clinical effect of the digital guide in the early implant restoration of second molars.

In the absence of contraindications to implants, implant repair is the preferred method to treat mandibular second molar loss. To compare the clinical effects of a traditional implant guide and digital implant guide in the early implant restoration of second molars. The study included 35 patients with second molar loss randomly divided into two groups. Eighteen patients in the experimental group had an implant procedure using a computer-aided design/computer-assisted manufacturing (CAD/CAM) digital implant guide, and 17 patients in the control group had the procedure using a traditional film pressing implantation guide. Then, the surgical procedure was completed using the two different implant guides. At 3 months after surgery, four parameters including screw hole exit position, coronal deviation of the implant site, disease improvement rate, and clinical effects, which included marginal adaptation, anatomic form, marginal discoloration, postoperative sensitivity, surface roughness, and secondary caries of the upper prosthesis were compared between the two groups. The screw hole exit position in the experimental group was directed to the functional cusp of the opposite jaw, and there was a statistically significant difference between the two groups. There was no statistically significant difference in the rate of disease improvement and the clinical effect of the upper prosthesis between the two groups. There was no statistically significant difference in the bilateral coronal deviation and deviation direction of implants in the two groups. The bilateral coronal deviation of the experimental group was smaller than that of the control group. The digital implant guide can effectively reduce the deviation of the screw hole and the upper prosthesis in the restoration of the second molar. The prosthesis used in the experimental group had a good clinical outcome, which provides a theoretical basis for the restoration of the posterior molar.

Customized Zirconia Crown in Pediatric Dentistry From Concept to Reality

Catering a tooth-colored restoration in a single sitting is the fundamental objective of chairside digital dentistry with computer-aided design/computer-assisted manufacturing (CAD/CAM) technology, which became a legitimate reality with the initiation of ceramic reconstruction (CEREC) workflow. CAD/CAM dentistry has evolved through an amalgamation of diverse software and hardware upgrades since its launch to a viable chairside technology that allows pediatric dentists to treat patients in a single visit. Nowadays, CAD/CAM of dental restorations has become an ingrained fabrication process, especially for zirconium restorations. In this report, we have presented three cases to exemplify the clinical use of chairside digital dentistry (i.e., CEREC workflow) for the fabrication of a customized zirconium restoration in a single sitting to restore form, function, and occlusion for grossly decayed and decalcified primary molars, as well as esthetics for primary anterior teeth with utmost comfort of child patients with single-sitting treatment modality.

The Effect of Thermocycling on Fracture Resistance of CAD- CAM and 3D Printing Provisional Prosthesis

This study aims to assess how thermal cycling affected the fracture strength of temporary restorations made using additive 3D printing procedures and computer-aided design- computer-assisted manufacturing (CAD/CAM), subtractive (milling) methods. For full coverage crowns, a dento form upper molar tooth was created. A second oral scanner digitally scanned developed model. Duplication of the metal dies was made using the master die (chrome cobalt alloy). A total of 40 samples were created and split into two groups: 20 were created using CAD/CAM technology with a (Bilkim) CAD PMMA disc and 20 were created using 3D printing with Asiga dentatooth resin. Thermal cycles (1250 cycles, 5-55 °C) were applied to 10 samples from each group. After that, a universal testing device determined the fracture resistance for each sample. The mean with standard deviation values of fracture resistance were recorded for the milled group before thermocycling (560.50 ±83.581 newton) and after thermocycling (901.00± 311.598 newton) meanwhile the mean ± stander deviation value was recorded with the printed group before thermocycling (1972.50±399.181 Newton) and after thermocycling (2284.10±239.001 Newton), it was found that the printed group recorded statistically significant higher fracture resistance mean value than the milled group. Provisional crowns constructed using the 3D printing technique showed higher fracture resistance compared to the temporary milled crowns.

Restoring non-restorable with the help of customized digital solutions: A review

This article aims to provide a comprehensive literate review on endocrown / customized digital restoration and how they might be a better option for hopeless decayed tooth. Dentist might be hesitant to apply such a successful treatment option for grossly decayed /fractured /traumatic teeth in their clinical practice because it’s not as widely used as other conventional methods. Here we review about innovative treatment approach for endodontically treated teeth, using a digital workflow with IOS and computer-aided design/computer-assisted manufacturing (CAD/CAM) fabrication of restoration. Endocrowns/ customized digital restoration constitutes a reliable approach for restoring severely damaged tooth as they are more precise, aesthetic and time saving.

The occlusal precision of milled versus printed provisional crowns

ObjectivesThe aim of this study was to compare the occlusal precision of computer-aided-design/ computer-assisted-manufacturing (CAD/CAM) milled versus 3D printed polymethylmethacrylate (PMMA) temporary prosthetic crowns , starting from the same digital CAD design. Materials and methodsThe study sample included 34 patients presenting 34 premolars in need of prosthetic rehabilitation: a total of 68 temporary crowns were manufactured, 34 of which milled and 34 printed. Immediately after manufacturing, the milled and printed provisionals were scanned with a desktop scanner (E1, 3Shape) to obtain STL files, that were superimposed to the original CAD design in order to identify the occlusal trueness (Analysis A). A second occlusal comparison was performed by scanning both kind of provisional after being placed intraorally with Trios scanner (3 Shape); intraoral scans were obtained in order to compare STL files of provisionals before and after occlusal adjustments (Analysis B). The occlusal trueness was identified at three reference points, P1 (vestibular cusp), P2 (palatal / lingual cusp), P3 (central fossa). The statistical analysis was performed using the R 3.4.3 statistical software (The R Foundation for Statistical Computing), with a significance level of p <0.05. ResultsOverall, the printed crowns showed lower occlusal differences than the milled crowns, when compared to the CAD design file, with a statistically significant difference in P1 (difference of 0.025 ± 0.046 mm), P2 (difference of 0.027 ± 0 0.044 mm) and P3 ( difference of 0.018 ± 0.050) for Analysis A (p <0.05). In the Analysis B the direct comparison between the degree of average difference between the pre-adjustment and the post-occlusal adjustment of the milled and printed crowns shows that the printed crowns have lower occlusal mean difference values in all three points compared to the milled ones (difference of 0.146 ± 0.273 mm in P1, 0.285 ± 0.360 mm in P2 and 0.257 ± 0.277 mm in P3). ConclusionsWithin the limitation of this study, the data obtained showed a better occlusal surface dimensional accuracy of the 3D printed provisional crowns, when compared to the milled ones. Comparing the results obtained, it is possible to assume that the intraoral scans also had a contribution to occlusion, beside the manufacturing method. 3D printing can be successfully applied for manufacturing temporary PMMA crowns.

Digital Applications of Maxillofacial Reconstruction– A systematic review

Objectives: Many patients with maxillofacial defects require maxillofacial prosthetic rehabilitation due to cancer, trauma, or congenital diseases. Adequate surgical and prosthetic treatment planning is required to achieve satisfactory morphological and functional results. Before computer-aided design/computer-assisted manufacture (CAD/CAM) technology was introduced, conventional methods have been used to reconstruct the facial form, which involved making impressions, obtaining models and fabricating the prosthesis all of which is time consuming and requires multiple visits. A rapid progress has been made with advances in digital technology, such as milling systems, rapid prototyping, three-dimensional (3D) scanning, and 3D printing, which has improved the patients’ expectations, the functional and esthetic treatment outcomes. Materials and methods: An electronic search was conducted in the Cochrane, PubMed (MEDLINE), and ScienceDirect databases between July 2000 and October 2020. A manual search was also performed to cover all digital aspects of the maxillofacial prosthesis. The inclusion criteria were randomized clinical trials, prospective or retrospective cohort, and cross-sectional studies performed on humans with at least 1 year of follow-up and published within the last 20 years. Results: The results showed that the used technologies in a digital workflow of auricular, orbital and nasal prosthesis reduce the manufacturing time and allow the manufacture of high-quality prostheses for missing facial parts. The methodology provides a good position for further development issues and is usable for clinical practice. Conclusion: Utilization of digital technologies in the facial prosthesis manufacturing process can be a good contribution for higher patient comfort and production efficiency but also comes with a higher initial investment and greater demands for experience with software tools.

A Retrospective Clinical Study on 1075 Lithium Disilicate CAD/CAM Veneers with Feather-Edge Margins Cemented on 105 Patients.

To evaluate the clinical performance of lithium disilicate (LiDiSi) computer-aided- design/computer-assisted-manufacturing (CAD/CAM) veneers with feather-edge margins. Over 4 years (2015-2019), 1075 LiDiSi veneers with feather-edge margins were fabricated with a fully digital workflow and cemented on 105 patients. The outcome variables were survival of the restorations, colour matching, quality of the ceramic surface, presence of marginal discolouration and marginal integrity. The last four variables were assessed using the modified California Dental Association (CDA) and Ryge criteria. The mean observation period was 30.8 months. The cumulative survival rate was 99.83%. At the last follow-up control, the colour matching of the surviving 1074 restorations was rated Alpha (1064 veneers, 99.06%) and Bravo (10 veneers, 0.94%); the ceramic surface was rated Alpha (1070 veneers, 99.62%) and Bravo (4 veneers, 0.38%); the marginal discolouration was rated Alpha (1069 veneers, 99.53%) and Bravo (5 veneers, 0.47%); and the marginal integrity was rated Alpha (1070 veneers, 99.62%) and Bravo (4 veneers, 0.38%). CAD/CAM LiDiSi veneers with feather-edge margins fabricated with a fully digital workflow showed good clinical performance in terms of survival, colour matching, ceramic surface, marginal discolouration and integrity. Further, prospective and long-term studies are needed to confirm these positive results.

Biomechanical effects of original equipment manufacturer and aftermarket abutment screws in zirconia abutment on dental implant assembly

The use of aftermarket computer-aided design/computer-assisted manufacturing (CAD/CAM) prosthesis components in dental implants has become popular. This study aimed to (1) compare the accuracy of aftermarket CAD/CAM screws with that of original equipment manufacturer (OEM) abutment screws and (2) examine the biomechanical effects of different abutment screws used with zirconia abutment in an implant fixture by using three-dimensional finite element analysis (FEA). Significantly different measurements were obtained for the aftermarket CAD/CAM and OEM screws. The FEA results indicated that under the same loading condition, the maximum stress of the aftermarket CAD/CAM screws was 15.9% higher than that of the OEM screws. Moreover, the maximum stress position occurred in a wide section of the OEM screws but in the narrowest section of the aftermarket screws. The stress of the OEM zirconia abutment was 14.9% higher when using the aftermarket screws than when using the OEM screws. The effect of the manufacturing differences between aftermarket and OEM screws on the clinical effect of aftermarket screws is unpredictable. Therefore, aftermarket screws should be cautiously used clinically.

A Severely Damaged Mandibular First Molar Restoration with CAD/CAM Customized Hybrid Ceramic Post and Core by Direct Intraoral Impression: A Case Report

The outcome of the teeth with coronal restoration may be unforeseeable when they need root canal therapy due to apical periodontitis, especially at the existence of a post. This case report describes a digital restoration strategy for the preservation of a serious defect tooth (left mandibular first molar). Tooth #36 with 10 years of a crown and post restoration needed root canal therapy due to apical periodontitis. After removal of the crown and cast post, the residual tooth showed fragility, and the distal root canal was seriously destroyed due to the post insertion. Selecting a suitable post was significant for the retention of the core to support the coronal restoration after the completion of the root canal therapy and apical barrier. The prefabricated fiber post and metal cast post were not good selections for the distal root canal. Therefore intraoral scanning was performed on the tooth and digitized to design a three-dimensional model of customized post-core and full crown by the Computer-Aided Design/Computer- Assisted Manufacture (CAD/CAM) technique. A 14-month follow-up showed a promising clinical and radiographic outcome. The digital CAD/CAM technique converted the concave surface of the root canal into the convex surface of the post, and fabricated an anatomical post and core using hybrid ceramic material close to the elastic modulus of natural dentin. It improved the biomechanics of this tooth #36 and reduced the occurrence of root fracture.

Effects of Khat on Surface Roughness and Color of Feldspathic and Zirconia Porcelain Materials under Simulated Oral Cavity Conditions.

Background and Objectives: Khat chewing is considered as a daily habit that is practiced by more than five million people globally. The effect of khat chewing on the surface roughness and the color stability of natural teeth and the material used in the fabrication of dental prosthesis remains unknown. This study was conducted to explore and compare the effect of khat homogenate (KH) on the surface roughness (Ra) and the average color changes (ΔE*) amongst natural teeth and selected shades from different porcelain types, namely, feldspathic metal ceramic (MC) VM13, computer-aided design/computer assisted manufacture (CAD/CAM) feldspathic (Vitablocs Mark II), and multilayer zirconia (Ceramill Zolid PS) porcelains. Materials and Methods: Seventy samples were prepared from natural teeth, feldspathic MC, CAD/CAM Vitablocs Mark II, and zirconia porcelain. The Ra values were measured using a profilometer and expressed in micrometers, whereas the ΔE* values were measured using VITA Easyshade® V spectrophotometer for all samples before and after frequent immersion and thermocycling in KH for 30 days. The surface topography was used to assess the materials surfaces (glazed or polished) after KH immersion by using a white light interferometry machine. Results: Results revealed that the Ra and the ΔE* values of the different types of tested porcelain were influenced by KH. The order of surface roughness values was glazed or polished MC > polished Zircon > polished Vitablocs Mark II > natural teeth. The lowest ΔE* values were recorded for glazed Vitablocs Mark II and MC, and the values could be arranged as polished zircon > natural teeth > glazed zircon > polished MC > polished Vitablocs Mark II. P values were significantly varied (<0.001) among all the tested groups, except the zircon group (>0.05) for both Ra and ΔE*. Conclusions: KH significantly affected both surface parameter and color of glazed or polished porcelain materials and natural teeth.

An Innovative Treatment Approach Using Digital Workflow and CAD-CAM Part 1: The Restoration of Endodontically Treated Molars in Children.

Stainless steel crowns are the most popular restoration technique for young permanent first molars treated endodontically. However, these restorations are not aesthetically appealing and need to be replaced. Endocrowns constitute a reliable approach for restoring severely damaged molars and premolars. Intraoral scanners (IOSs) are well tolerated by children and are easily and quickly implemented. We present an innovative treatment approach for endodontically treated teeth in children, using a digital workflow with IOS and computer-aided design/computer-assisted manufacturing (CAD/CAM) fabrication of the restoration. The protocol involves a thorough diagnostic phase and comprehensive treatment planning. Among the factors to be considered are the child’s behavior, the parents’ cooperation and compliance, and initial preparation including inhalation sedation, effective local anaesthesia and the use of a rubber dam. Full attention should be given to 1–2 mm of ferruling by the endocrown, which should be appropriately prepared to accommodate endocrowns for molars. IOSs include scanning of the prepared tooth and its antagonist, and scanning of the bite. CAD-CAM preparation of the restoration is followed by restoration bonding and follow up. Digital workflow should be considered in the treatment of endodontically treated molars since the high accuracy of the scanning enables definitive restoration in young patients.

Preservation of Soft Tissue Contours Using Computer-Aided Design/Computer-Assisted Manufacturing Healing Abutment with Guided Surgery in the Esthetic Area: Case Report

This case report describes a digital workflow for a computer-aided design/computer-assisted manufacturing (CAD/CAM) healing abutment used in immediate implant placement in the esthetic zone. The design of the healing abutment was based on the existing tooth anatomy in order to provide anatomical support to the gingival tissues and to preserve the gingival contours of the natural tooth. This approach enhances the esthetic outcome of the definitive implant restoration. The surgical procedure including the guided bone regeneration is simplified, postoperative morbidity is reduced, and excessive occlusal loading during healing is limited.

Trueness of CAD/CAM digitization with a desktop scanner \u2013 an in vitro study

BackgroundDesktop scanners are devices for digitization of conventional impressions or gypsum casts by indirect Computer-Aided Design/Computer-Assisted Manufacturing (CAD/CAM) in dentistry. The purpose of this in vitro study was: 1, to investigate whether virtual models produced by the extraoral scanner have the same trueness as sectioned casts; and 2, to assess if digitization with an extraoral scanner influences the surface information.MethodsA polimethyl-methacrilic acid (PMMA) cast and a reference scanner (TwoCam 3D, SCAN technology A/S, Ringsted, Denmark; field of view 200 mm, resolution 0.1 mm ± 0.025 mm) were used to create the reference data in standard tessellation format (STL). According to the extraoral CAD/CAM digitization steps, impressions, mastercasts, and sectioned casts were made, and STL files were generated with the reference scanner. The pivotal point of the study was to digitalize these sectioned casts with the extraoral scanner (Straumann CARES Scan CS2 Visual 8.0 software, InstitutStraumann AG, Basel, Switzerland) and STL files were exported. Virtual caliper measurements were performed. Absolute deviations were compared using multilevel mixed-effects linear regression. Relative distortions were calculated with mean absolute errors and reference values.ResultsDifferences were observed in measurements of tooth sizes. All four prepared teeth were affected. No relationship was observed in relative deviations. Absolute differences between all the indirect digitization steps considering arch distances were: impressions, − 0.004 mm; mastercasts, 0.136 mm; sectioned casts, − 0.028 mm; and extraoral scanner, − 0.089 mm. Prepared dies on the virtual casts (extraoral scanner) were closer to each other than those on the sectioned gypsum casts. Relative deviation calculations revealed no relationship with the position of the dies in the arch.ConclusionThe trueness of the virtual models generated by the extraoral scanner system used in this study was different from the dimensions of the sectioned casts. The digitization of gypsum casts changes both the dimensions of dies and the distances between the dies. The virtual casts had smaller distances than any distances measured at previous steps. Either bigger dies or longer distances did not result in greater distortions. We cannot, however, generalize our results to all scanners available on the market, because they might give different results.

Influence of Different Luting Systems on Microleakage of CAD/CAM Composite Crowns: A Pilot Study.

To investigate whether (1) the curing mode and (2) the use of the corresponding or noncorresponding crown luting system have an impact on the microleakage of computer-aided design/computer-assisted manufacture (CAD/CAM) composite crowns after chewing simulation. Two CAD/CAM composite blocks (Lava Ultimate [n = 20] and LuxaCam Composite [n = 20]) and their luting systems and curing modes (light curing [LC] or chemical curing [CC]) were investigated. A dye penetration test was used to detect the presence of microleakage. Independently of the luting system, the LC groups showed a significantly lower microleakage compared to the CC groups (P < .05). Furthermore, the CC groups exhibited a reduction of microleakage if the CAD/CAM block and luting system were from the same manufacturer. For the CC mode, the corresponding block and luting system should be used.

Zirconia Translucency and Cement Systems as Factors Influencing the Zirconia-Titanium and Zirconia-Zirconia Shear Bond Strength.

To evaluate the bonding ability of self-adhesive and dual-cure resin cement systems applied to zirconia materials of different translucency in combination with each other and with titanium. Computer-aided design/computer-assisted manufacture (CAD/CAM) disks of three different zirconia materials (Zenostar MO 0 [medium opacity], MT 0 [medium translucency], and T 1 [translucent], Wieland Dental) were milled and hard sintered in order to obtain cylindrical samples of either 12 mm high × 12 mm diameter (used as a substrate) or 12 mm high × 8 mm diameter (to be bonded to the substrate). CAD/CAM disks of titanium (Starbond Ti4 Disc, S&S Scheftner) were milled in order to obtain a cylinder shape (12 mm high × 8 mm diameter to be bonded to the zirconia substrate). The bonding surfaces were sandblasted with alumina particles (70 μm/2 ATM). Two resin cement systems were tested in this study: a self-adhesive resin cement (SpeedCEM Plus, Ivoclar Vivadent) and a dual-cure resin cement (Variolink Esthetic DC, Ivoclar Vivadent) in combination with a primer (Monobond Plus, Ivoclar Vivadent). The smaller cylinders were bonded to the substrate following the manufacturer's instructions. After 24 hours at 37°C storage, each specimen was subjected to shear bond strength testing in a universal testing machine. The substrate was fixed to the machine, and shear force was applied to the small cylinder close to the bonding interface. Shear bond strength data were statistically analyzed by a three-way analysis of variance (ANOVA) followed by the Tukey test for post hoc comparison (P < .05). No significant differences were found between substrates in the shear bond strength test (P = .078). Variolink Esthetic DC showed a statistically significantly higher bond strength compared with the SpeedCEM Plus (P = .001) with the exception of Zenostar MT substrate (P = .014). The resin cement systems showed high shear bond strength values when zirconia was resin bonded to either titanium or the corresponding zirconia substrate. Different zirconia translucencies did not affect the bond strength. The use of MDP primer and a dual-cure cement showed statistically significantly higher strength compared with the self-adhesive resin cement system with the only exception being the bonding of the translucent zirconia Zenostar MT.

Tensile Bond Strength of Three Custom-made Tooth-Colored Implant Superstructures to Titanium Inserts

Statement of the Problem: Hybrid abutments are made of a titanium implant insert and a ceramic component. The tensile bond strength between the titanium implant insert and the ceramic component is not still clearly known. Purpose:This in vitro study aimed to compare the tensile bond strength of the titanium insert to ceramic components made of milled lithium disilicate, milled zirconia, and pressable lithium disilicate. Materials and Method: To standardize the shape and dimension of the ceramic components, a single computer-aided design/computer assisted manufacturing (CAD/CAM) superstructure was designed with Dental Designer software. Based on this model, CAD milled zirconia (Zr), CAD milled Lithium disilicate (CAD-LD) and heat-pressed lithium-disilicate (H-LD) superstructures were fabricated (n=10 per group). They were bonded to the titanium inserts by using self-adhesive resin cement. The prepared superstructure-titanium insert complexes (hybrid abutments) were screwed into the implants with 35 Ncm torque. The tensile bond strength of the ceramic superstructures to the titanium inserts were recorded by the universal testing machine with a crosshead speed of 2 mm/min. The data were analyzed by using one-way ANOVA and Tamhane post-hoc test (p< 0.05). Results:The mean±SD of tensile bond strength was 328.50±30.4 N in CAD-LD, 257.30±23.8 N in H-LD, and 242.20±21.2 N in Zr groups. One-way ANOVA revealed the groups significantly different in terms of the tensile bond strength (p< 0.001). Tamhane post-hoc test showed a significant difference between the CAD-LD and the two other groups (p<0.001); however, no statistically significant difference was detected between the H-LD and Zr groups (p= 0.39). Conclusion:It can be concluded that the CAD-LD has higher bond strength to titanium insert compared with the H-LD and Zr groups. Therefore, they might be clinically more beneficial in high-esthetic areas.

Treatment of Gingival Recessions Associated with Noncarious Cervical Lesions Using Natural Inlays Before Coronally Advanced Flap Application: A Case Series.

Treatment of gingival recessions associated with noncarious cervical lesions (NCCL) can be a challenging clinical situation for clinicians. Both periodontal and restorative treatment can be necessary for this kind of defect. By using both digitally precise computer-aided design/computer-assisted manufacture (CAD/CAM) procedures and natural inlay (NI) material for restoration of defects before the coronally advanced flap (CAF) surgery, attachment of soft tissues on the root surface can be achieved successfully. Seven nonsmoking patients with NCCL associated with gingival recessions in the maxillary esthetic zone were treated with NI restoration before CAF surgery. All of the included patients needed at least one tooth extraction, and extracted teeth were used for NI restoration for the CAD/CAM milling procedure. After application of the restorative material onto NCCL defects, CAF surgery was performed for root coverage. The primary outcome was increased mean root coverage percentage and clinical attachment gain after a 6-month follow-up period. Successfully restored NCCL defects were covered with CAF, and 91.67% mean root coverage was achieved with a 1.98-mm attachment gain. Additionally, 71.42% of the root surfaces covered completely. Application of NI restoration materials with CAD/CAM techniques can be a promising procedure for the restoration of NCCL defects before periodontal surgery. This method can achieve a better clinical attachment after root surface coverage.

Retrospective and Clinical Evaluation of Aftermarket CAD/CAM Titanium Abutments Supporting Posterior Splinted Prostheses and Single Crowns.

To evaluate the clinical outcomes of aftermarket computer-aided design/computer-assisted manufacturing (CAD/CAM) titanium abutments supporting splinted prostheses and single crowns in the posterior region. This study retrospectively evaluated the records of patients who received posterior implant-supported splinted restorations and single crowns supported by aftermarket CAD/CAM titanium abutments. Recall and clinical examination of the patients were performed between January 2017 and February 2018. A logistic regression was conducted to evaluate the influence of variables on the occurrence of complications and success rates. Correlations between the bone-level change and variables were calculated using the Spearman correlation. One hundred thirty-five patients with 287 implants (86 crowns and 97 splinted prostheses) were recalled and examined clinically and radiographically after a mean observation period of 6.3 ± 1.2 years (range 4.1 to 9 years). Failure of 3 implants led to a survival rate of 99.0%. Complications included 18 (9.8%) ceramic chippings, 15 (8.2%) screw loosenings, 8 (4.4%) decementations, 52 (38.5%) patients with peri-implant mucositis, and 9 (6.7%) patients with peri-implantitis. A significantly higher incidence of ceramic chipping occurred with bruxers (odds ratio [OR] = 3.939, 95% confidence interval [CI] = 1.28-12.09, P < .05). All screw loosenings occurred in single crowns. All decementations were observed in restorations cemented with temporary cement. Marginal bone loss around implants was significantly correlated with smoking (r = -0.155, P < .05). Hypertension was significantly associated with peri-implant mucositis (OR = 4.7, 95% CI = 1.65-13.39, P < .05). The technical success rate was 80.1%. The biologic success rate was 57%. There was no association between the restoration type and the success rates of the restorations. Using aftermarket CAD/CAM titanium abutments to support posterior restorations yielded comparable survival and success rates after a mean observation period of 6 years. However, in light of the relatively high incidence of screw loosenings, especially in patients receiving single-implant crowns, informing patients of the additional chairside aftercare with this type of treatment option is recommended.