PURPOSE: The purpose of this virtual analysis study was to compare the accuracy and precision of 3-dimensional (3D) ear models generated by scanning gypsum casts with a smartphone camera and a desktop laser scanner.
MATERIAL AND METHODS: Six ear casts were fabricated from green dental gypsum and scanned with a laser scanner. The resultant 3D models were exported as standard tessellation language (STL) files. A stereophotogrammetry system was fabricated by using a motorized turntable and an automated microcontroller photograph capturing interface. A total of 48 images were captured from 2 angles on the arc (20 degrees and 40 degrees from the base of the turntable) with an image overlap of 15 degrees, controlled by a stepper motor. Ear 1 was placed on the turntable and captured 5 times with smartphone 1 and tested for precision. Then, ears 1 to 6 were scanned once with a laser scanner and with smartphones 1 and 2. The images were converted into 3D casts and compared for accuracy against their laser scanned counterparts for surface area, volume, interpoint mismatches, and spatial overlap. Acceptability thresholds were set at <0.5 mm for interpoint mismatches and >0.70 for spatial overlap.
RESULTS: The test for smartphone precision in comparison with that of the laser scanner showed a difference in surface area of 774.22 ±295.27 mm2 (6.9% less area) and in volume of 4228.60 ±2276.89 mm3 (13.4% more volume). Both acceptability thresholds were also met. The test for accuracy among smartphones 1, 2, and the laser scanner showed no statistically significant differences (P>.05) in all 4 parameters among the groups while also meeting both acceptability thresholds.
CONCLUSIONS: Smartphone cameras used to capture 48 overlapping gypsum cast ear images in a controlled environment generated 3D models parametrically similar to those produced by standard laser scanners.
PURPOSE: The purpose of this paper is to systematically review all the prosthetic techniques that have been used in the oral rehabilitation of patients with microstomia.
MATERIALS AND METHODS: Data sources, including PubMed, Google Scholar, SCOPUS and Web of Science, were searched for case reports and case series published through September 2017. Three investigators reviewed and verified the extracted data. Only case reports and case series on prosthetic rehabilitation in microstomia patients published in the English language were considered eligible.
RESULTS: A total of 212 records were identified from the database search. Forty duplicate records were removed. The remaining 172 articles were assessed for eligibility, and 139 articles were removed because they did not satisfy the inclusion criteria. A total of 34 cases (including 32 case reports and 1 case series) were finally included in the qualitative analysis. The review revealed the use of a modified impression technique with flexible and sectional trays to record impressions in patients with microstomia. Modified forms of oral prostheses ranging from sectional, flexible, collapsible and hinged dentures to implant-supported prosthesis were fabricated to overcome the limited mouth opening. The success of the prosthetic technique primarily depended on the extent of the microstomia and the nature of the cause of the microstomia.
CONCLUSION: Even though the patient acceptance of the prosthetic techniques summarized in the systematic review were high, long-term success rates for each option could not be assessed because of the short follow-up time in most of the included case reports and series.
METHODS: Forty direct impressions of a mandibular reference model fitted with six dental implants and multibase abutments were made using VPES and PE, and implant casts were poured (N = 20). The VPES and PE groups were split into four subgroups of five each, based on splinting type: (a) no splinting; (b) bite registration polyether; (c) bite registration addition silicone; and (d) autopolymerizing acrylic resin. The accuracy of implant-abutment replica positions was calculated on the experimental casts, in terms of interimplant distances in the x, y, and z-axes, using a coordinate measuring machine; values were compared with those measured on the reference model. Data were analyzed using non-parametrical Kruskal-Wallis and Mann-Whitney tests at α = .05.
RESULTS: The differences between the two impression materials, VPES and PE, regardless of splinting type, were not statistically significant (P>.05). Non-splinting and splinting groups were also not significantly different for both PE and VPES (P>.05).
CONCLUSIONS: The accuracy of VPES impression material seemed comparable with PE for multi-implant abutment-level impressions. Splinting had no effect on the accuracy of implant impressions.