ABSTRACT
OBJECTIVES: Reports concerning the accuracy of intraoral digital impression systems are limited. This study aimed to assess the effects of scan body types and shapes on digital impression accuracy and scanning time in all-on-four restorations. METHODS: This in vitro study was conducted with two acrylic maxillary models. Two implant systems with different connection types (internal trilobe and external hexagon connection) were inserted according to the all-on-four design. Scanning was performed using Doowon, NT-Trading, and DESS scan bodies. Changes in implants' positions (ΔR) and angulation (ΔA), and the implants' distance from the reference pin (ΔD) compared with the actual model were determined. Scanning times were also measured and compared. RESULTS: The effects of implant connections and scan bodies on ΔR and ΔA were significant (p ⟨0.05). Implant angulation could also affect ΔA (p=0.019). ΔD was only affected by scan body (p ⟨0.001). The three scan bodies were significantly different in terms of scanning time (p=0.001). CONCLUSION: The results showed that scan body type and shape, and implant connection and angulation could affect digital impression accuracy in all-on-four restorations. For both internal and external connections, the NT-Trading and DESS scan bodies had the shortest and longest scanning times, respectively.
Subject(s)
Dental Implants , Dental Impression Technique , Computer-Aided Design , Dental Impression Materials , Dental Prosthesis, Implant-Supported , Models, DentalABSTRACT
OBJECTIVES: This in vitro study aimed to compare the internal and marginal discrepancies of endocrowns fabricated from different ceramics before and after adjustment. METHODS AND MATERIALS: Thirty-six endocrowns were fabricated from lithium disilicate (IPS e-max CAD), zirconia-reinforced lithium silicate (Suprinity), and polymer-infiltrated ceramic network (Enamic) using a CEREC intraoral scanner and milling unit. A reference point matching scan protocol was used to measure the endocrowns fit. The mixed ANOVA was used to analyze the data, and α=0.5 was considered as the significance level. RESULTS: There was no significant interaction between the fabrication materials and adjustment (P⟩0.05). Type of the materials did not change discrepancies at cavosurface, line angle, cavity wall, and pulpal floor (P⟩0.05). On the contrary, adjustment significantly decreased the discrepancies at all four sites (P⟨0.001). There were significant differences between every two sites before adjustment (P⟨0.001). After adjustment, except for cavosurface and cavity wall (P=0.058), the differences between other sites remained significant (P⟨0.001). CONCLUSIONS: IPS e-max CAD, Suprinity, and Enamic endocrowns were not significantly different regarding internal and marginal discrepancies. However, it is suggested that these materials be adjusted to fall in a clinically acceptable range to minimize the risk of caries and periodontal disease.
Subject(s)
Crowns , Dental Marginal Adaptation , Ceramics , Computer-Aided Design , Dental Porcelain , Dental Prosthesis Design , Materials TestingABSTRACT
Treatment planning poses difficulties in edentulous patients for orthognathic surgery prediction and fixation.Treatment of severe class III malocclusion frequently requires orthognathic surgical procedures. For such patients, orthognathic surgery would be the only option before prosthetic rehabilitation.This clinical report describes step-by-step fabrication of a surgical splint for an edentulous 22-year-old patient with a severe class III malocclusion.The patient wound up in class I occlusions and stable prosthodontic rehabilitation.Using splints for planning and guiding the surgery in edentulous patients facilitates accurate positioning of the jaws and saves time in the operating room.
ABSTRACT
In this article, three techniques for maxillo-mandibular relationship for Replace-Select implants are described. The use of healing abutments, planning abutments, and Impression copings are presented, and the advantages and disadvantages are discussed.
