Evaluation and comparison of the accuracy of three intraoral scanners for replicating a complete denture.

STATEMENT OF PROBLEM: Technological advances in digital acquisition tools have increased the scope of intraoral scanners (IOSs), including scanning a removable complete denture (RCD) to replicate it. However, studies assessing the accuracy of IOSs for replicating a maxillary or mandibular RCD are lacking. PURPOSE: The purpose of this in vitro study was to evaluate the accuracy (trueness and precision) of 3 IOSs while replicating a maxillary and mandibular RCD. MATERIAL AND METHODS: One maxillary and 1 mandibular RCD were scanned with a desktop scanner (D2000) to obtain the reference model. Two operators scanned each RCD 5 times with 3 different IOSs (TRIOS 4, Primescan, and IS3800), following a predefined acquisition protocol. The 60 study models obtained were compared with the reference model using the Geomagic software program. For each comparison, the mean and standard deviation of discrepancy were calculated. Distances were measured on both the reference and the study model, and differences were calculated to assess whether sagittal or transverse deformations were present. The tolerance percentage of the volume of the digital model compared with the volume of the reference model was determined (difference tolerance was set at 0.1 mm). A univariate analysis of variance followed by a post hoc analysis using the Student-Newman-Keuls (α=.05) test was performed to determine the truest and the most precise IOS. RESULTS: The TRIOS 4 and Primescan IOSs had comparable trueness, with mean dimensional variations of 47 ±27 µm and 57 ±8 µm respectively compared with the reference model. The IS3800 had a lower trueness (98 ±35 µm). Primescan was significantly more precise with a mean standard deviation of 64 ±15 µm (P<.05). The TRIOS 4 (141 ±48 µm) and IS3800 (129 ±24 µm) had comparable precision. Primescan showed the least sagittal and transverse deformation. CONCLUSIONS: This study determined that an RCD can be replicated using an IOS, although all IOSs did not have equal accuracy. An in vivo study needs to assess whether this procedure is clinically acceptable.

A new digital denture procedure: a first practitioners appraisal.

BACKGROUND: Historically, the complete removable denture is the last prosthetic procedure to switch to digital techniques whose advantages are mainly observed in the laboratory stages; however, it is not possible to measure the depressibility of the oral mucosa using optical cameras, thus conventional impression techniques are still necessary. This article describes the clinical and laboratory procedure and practitioners appraisal of the first fifteen digitally designed complete removable dental prostheses. METHODS: Several systems are now available including the Wieland® Digital Denture® which offers a complete procedure. This system is composed of a five axis-milling machine combined with a laboratory scanner and a design software application. Fifteen rehabilitations were carried out using the Wieland® system. RESULTS: The practitioner's role is simplified by intraoral recording with a central point and a reduced number of sessions. The prosthesis laboratory requires considerable investment in learning and equipment, making it possible to obtain ideal mounting assemblies in accordance with the occluso-prosthetic concept of bilateral balanced occlusion. The absence of polymerization and therefore of base deformation risks reduce the equilibration step. Finally, the creation of templates as an alternative to the assembly of teeth on wax makes it possible to functionally validate (masticatory and phonatory) the future dentures. However, this procedure still presented some limitations in terms of scanning and software scope of applications. CONCLUSION: Digital denture design software is relatively efficient and helps to standardize clinical results. However, to this date, improvements of the software are still required for a routine use.

Ceramo-Metal Crown or Cad-Cam Rehabilitation: Patient and Practitioner Appraisal.

Crowns produced using CAD-CAM technology must be evaluated so they can be integrated in the dentist's therapeutic arsenal. To this end, an evaluation tool for the fixed element units was developed and tested in a randomized cross-over pilot study. At a hospital centre, 10 single crowns from the same dental preparation and produced using CEREC technology were compared to Ceramo-Metal Crowns produced using a conventional procedure. Practitioners generally evaluated CEREC crowns more positively, corroborating the subjects' preference for these crowns. The CEREC technology used in a hospital setting meets the requirements of both patients and practitioners.

Aesthetic and Functional Rehabilitation of Patients with Genetic Microdontia: A Multidisciplinary Approach.

This case report presents the treatment of a 33-year-old patient with a genetic, generalized microdontia of permanent teeth. Microdontia is a developmental dental anomaly of the teeth characterized by a decrease in their size. In the literature, treatment has been multidisciplinary, often utilizing orthodontics and implantology. However, for adult patients with generalized microdontia who do not benefit from these treatments as much, a combination of adhesive dentistry, endodontics and removable prostheses remains a therapeutic alternative to consider. Given the specificities of the patient and the nature of the care, the objective of this treatment option was to manage the patient's comfort while guaranteeing quality of care. A feature of this treatment was the use of general anesthesia for endodontic treatments and exodontia. Chairside CAD/CAM and adhesive dentistry reduced the chairside time and preserved healthy dental tissue.

Which variables should be controlled when measuring the granulometry of a chewed bolus? A systematic review.

The distribution of food particles in a chewed bolus characterizes the food destruction after food oral processing (FOP). Previous reviews report that it could be affected by a lot of parameters as the number of chewing strokes, the dental status, but the conditions for producing reproducible data allowing inter-studies comparison have not been clearly described yet. This systematic review aims to identify the variables that can affect bolus granulometry determination, and to calculate their relative weights in the median particle size (D50 ) variations. The systematic review focuses on granulometry expressed as D50 of the most used foods (peanuts, carrots, and almonds) and materials (Optosil and Optocal). Based on 58 studies, 5 variables among 60 being extracted could explain the D50 variations. Conceptual differences between the conditions for FOP should be considered. After Chewing-test, the bolus is collected after a predefined number of strokes and its granulometry characterizes the effects of the dental and muscular apparatus on food destruction, while after Mastication-test the bolus is collected at the swallowing threshold, and its granulometry reflects the outcome of the abilities of the subject to adapt his/her mastication behavior to food texture. Experimental conditions related either to physical sieving or image analysis used to analyze the collected boluses impact the D50 values. Finally, when type of test, sieving conditions, type of food or material, number of chewing strokes, and the oral status of the subjects are controlled, mean D50 values are reproducible and could be used for inter-studies comparisons. PRACTICAL APPLICATIONS: This review provides tables that could be useful to control mean D50 variations in further research.

Predictive Parameters of Oral Health Quality of Life in Complete Mandibular Denture Wearers Stabilized by Mini-Implants: A Two-Year Follow-Up Study.

The frequent instability of mandibular removable complete dentures affects patient Oral Health Related Quality of Life (OHRQoL). An innovative therapeutic strategy used to improve stability involves placing four symphyseal mini-implants. This study was aimed at assessing OHRQoL over time in subjects in which mini-implants were placed and exploring if certain parameters could predict the evolution of their OHRQoL. The OHRQoL of subjects with dentures was assessed using the Geriatric Oral Health Assessment Index (GOHAI) before (T0), 2-6 months (T1), twelve months (T2) and twenty-four or more months (T3) after mini-implant setting. Age, gender and chewing ability were tested as explanatory variables for the change in OHRQoL with time. Thirteen women and six men were included (mean age: 69 ± 10 years). After treatment, mean GOHAI scores at T1, T2 and T3 increased significantly (p < 0.001). The GOHAI-Add mean score was not affected by age or gender. Baseline chewing ability impacted the "functional" and "pain and discomfort" fields of the mean GOHAI scores (p < 0.05). The OHRQoL quickly improved after mini-implant placement in complete denture wearers and then stabilized over time. Baseline chewing ability can be used as a predictive parameter of OHRQoL.

Influence of the renewal of removable dentures on oral health related quality of life.

BACKGROUND: The renewal of removable dentures is often suggested to denture wearers subject to discomfort. However, the impact of this rehabilitation on patients' oral health related quality of life and their removable dentures related satisfaction is still unknown. This study was aimed at assessing these patient-centered outcomes and the potential impact of different factors. METHODS: A cohort of 116 patients in need of removable dental prostheses rehabilitation was recruited at a dental hospital over a period of 1 year. The subjects were separated into two groups according to their prosthesis experience (group in need of removable dentures renewal/group needing an removable dentures for the first time). Subjects were asked to answer the "Geriatric Oral Health Assessment Index" (GOHAI) and the "McGill Denture Satisfaction Instrument" before and after a prosthesis integration period (9-12 weeks). RESULTS: GOHAI scores were slightly higher for patients with removable dentures renewal (from 40.6 ± 10.3 to 47.1 ± 10.0, p < 0.001), independently of the type of prosthetic rehabilitation. However, the scores of the GOHAI functional field did not change. Subjects with no removable dentures experience presented an increase in their functional GOHAI score (p < 0.001). Regarding patient removable dentures related satisfaction, only the "Esthetic" (p < 0.001), "Chewing efficiency" (p < 0.001) and "Oral condition" (p < 0.01) items increased after prosthesis renewal. CONCLUSIONS: This study showed that renewing removable dentures only moderately improved the oral health related quality of life and removable dentures related satisfaction of patients, regardless of age, gender or type of rehabilitation. Other tasks are necessary such as the analysis of physiological parameters and qualitative research on patient's expectations.