Survival Rate of CAD-CAM Endocrowns Performed by Undergraduate Students.

OBJECTIVES: This study aimed to evaluate the success of computer-aided design-computer-aided manufacturing (CAD-CAM) endocrown restorations of endodontically treated teeth (ETT) performed by supervised undergraduate students. The study also intended to identify possible factors that may lead to failures. METHODS AND MATERIALS: This observational open cohort study was based on clinical data from endocrown restorations performed by residents and undergraduate students in their 4th, 5th, and 6th year from July 2011 to May 2018. The presence of a tooth with an endocrown on the arch was the main criteria used to calculate the survival rate of restored teeth. The quality of the remaining endocrowns was evaluated referring to the FDI criteria. The cases of failure were categorized into either favorable or unfavorable. RESULTS: A total of 343 ETT were restored with endocrowns in 315 patients. Among them, 199 patients encompassing 225 endocrowns were followed during a 56 ± 26 month period. The survival rate of restored teeth was found to be 81.8%, the estimated Kaplan-Meier survival rate being 71.8% at 9 years. Among the 41 failed cases, 32 were favorable (debonding and/or ceramic fractures) and 9 were unfavorable. CONCLUSION: Endocrown restorations of posterior ETT using CAD-CAM technologies could be carried out by undergraduates with a low risk of failure. Teacher supervision could be reinforced, covering all steps of each endocrown procedure in order to avoid failures due to insufficient thickness or loss of retention.

Stabilization of mandibular complete dentures by four mini implants: Impact on masticatory function.

OBJECTIVES: The frequent instability of mandibular removable complete dentures causes an alteration of mastication. An innovative therapeutic strategy involves placing four symphyseal mini implants. This study aimed at assessing the development of masticatory parameters and the impact on quality of life in subjects that underwent this procedure. METHODS: Eleven edentulous subjects (mean age 72±11 years) with unstable mandibular complete dentures were followed-up before (T0) and two - three months after (T1) mini implant setting. Physiological parameters (number of cycles, duration of sequence and frequency of mastication) during the mastication of food models and the bolus median particle size (d50) of carrot were evaluated at each time. Quality of life was assessed at T0 and T1 using the Global Oral Health Assessment Index (GOHAI). Parametric tests were used to test relationships between mastication, quality of life variations and mini implant setting, and to compare each parameter mean value at times T0 and T1. RESULTS: More subjects were able to chew carrot after setting the mini implants (8 subjects compared to 4 at T0). This improvement was accompanied by changes in kinematic parameters when chewing carrots, soft and hard model food, and by an improvement of their quality of life. However, the particle size values observed in the bolus remained higher than for normal dentate subjects (9.2±2.8mm). CONCLUSIONS: These results indicated that the placement of mini implants as retentive elements for mandibular full dentures had a positive impact on patients' masticatory function and quality of life. CLINICAL SIGNIFICANCE: The placement of mini implants has a positive impact on the masticatory function and oral health quality of life. The results suggest that this alternative procedure can be used as a treatment option for patients unable to receive conventional implants.

Evaluation of Cerec endocrowns: a preliminary cohort study.

This study aimed to evaluate clinical qualities and evolution on ceramic endocrowns produced with the Cerec 3D (Sirona). Endocrowns were produced in a hospital environment and evaluated according to the FDI criteria on the day of placement and 6 months afterwards. Each item was graded from 1 (good) to 5 (bad). A global score, as well as a score for aesthetics, functioning and biological integration was assessed for each evaluation. During the 6-month evaluation period, the scores were always related to good clinical quality, except for single crown restoration. The scores did not change between the two periods of evaluation.

[Evaluation of the professional dentists' ability to determine the tooth shade guide: a pilot study]. / Evaluation de la capacité des professionnels en odontologie à déterminer la couleur des teintiers: étude pilote.

BACKGROUND: During its clinical practice, the dentist is often faced with issues concerning the determination of teeth shade. This step is considered sensitive by numerous clinicians and dental laboratories. The objective of this study was to test the ability of professional dentists to visually determine the teeth color. MATERIAL AND METHODS: Eleven dentists classified 35 unmarked samples according to their hue, chroma and value from 2 standardized tooth shade guides Ivoclar-Vivadent (Chromascop) et Vita (3D Master). The ratio between the number of matching samples and the total amount of samples from each group was calculated and converted to a score between 0 and 10. RESULTS: Better scores were obtained for value and chroma with the 3D Master shade guide than with the Chromascop shade guide (p < 0.001). The opposite result was obtained for the hue (p < 0.05). Globally, better results were obtained for the value and chroma, the hue being the most difficult item to evaluate. A satisfying "color perception" was observed in 69% of the cases. CONCLUSION: The results of this study argue in favor of a specific training for tooth shade determination in Odontology.