Centric relation—A biological perspective of a technical concept

Background: Few terms and concepts have been so extensively debated in dentistry as the words 'centric relation' (CR). Debates involve its biological, diagnostic and therapeutic usefulness. Methods: A review of the literature on the current concepts on CR as a diagnostic or therapeutic aid in dentistry was provided. Clinical trials assessing the superiority of one CR recording method over the others to identify patients with temporomandibular disorders (diagnostic use) or to manage patients with prosthodontic or orthodontic needs (therapeutic use) were tentatively included. Results: Due to the absence of literature addressing either of the above targets, a comprehensive overview was provided. The diagnostic use of CR as a reference position to identify the correct position of the temporomandibular joint condyle within the glenoid fossa is not supported and lacks anatomical support. From a therapeutic standpoint, the use of CR can be pragmatically useful in prosthodontics as a maxillo-mandibular reference position when occlusal re-organization is warranted and/or when the position of maximum intercuspation is no longer available. Conclusions: The derived occlusal goals from a diagnostic misuse of CR are generally the result of circular reasoning, that is a technique is based on the recording of a certain condylar position that is believed to be 'ideal' and the treatment is considered successful when such position is shown by the specific instrument that was manufactured for that purpose. The term 'Centric Relation' might be replaced with the term 'Maxillo-Mandibular Utility Position'

Chewing performance of patients with worn dentition before and after restorations: A scoping review

BackgroundTooth wear is a multifactorial complex process related to the loss of dental tissue, due to chemical or mechanical processes, by abrasion, attrition, erosion. Restorative treatment represents an attempt to rebuild and recreate the lost structure. ObjectiveThis scoping review aims to investigate whether restorative treatment of worn dentition (either with direct or indirect adhesive composite adhesive procedures or with prosthetic techniques) can have an impact on the masticatory performance parameters. MethodsA scoping review was conducted on multiple databases (Pubmed, Medline CENTRAL, ICTRP), following the PRISMA guidelines. Abstracts of research papers were screened for suitability, and full-text articles were obtained for those who satisfied the inclusion and exclusion criteria. ResultsOnly one article meet the inclusion criteria of the review. Restorative treatment of worn dentition although have a positive impact on the self-report ability to chew, has no effect on the masticatory performance test. ConclusionAt the moment, not enough evidence to comment on the actual therapeutic role of restorative treatment on tooth wear is available. Clinicians, before taking any clinical decision, should carefully discuss with patients the needs and expectations of the treatment plan

A Force-Feedback Exoskeleton for Upper-Limb Rehabilitation in Virtual Reality

This paper presents the design and the clinical validation of an upper-limb force-feedback exoskeleton, the L-EXOS, for robotic-assisted rehabilitation in virtual reality (VR). The L-EXOS is a five degrees of freedom exoskeleton with a wearable structure and anthropomorphic workspace that can cover the full range of motion of human arm. A specific VR application focused on the reaching task was developed and evaluated on a group of eight post-stroke patients, to assess the efficacy of the system for the rehabilitation of upper limb. The evaluation showed a significant reduction of the performance error in the reaching task (paired t-test, p < 0.02

Toxic polyneuropathy of shoe-industry workers in Italy - A Clinical, neurophysiological and follow-up study.

Sono stati studiati numerosi casi di polineuropatia dovuta ad esposizione professionale a solventi industriali in diversi calzaturifici della provincia di Siena. Lo screening di 654 lavoratori ha permesso di identificare 98 casi di polineurite, di cui 16 gravi, 45 di media gravità e 37 senza sintomi neurologici obiettivi ma con le caratteristiche alterazioni elettrodiagnostiche. La studio longitudinale di 53 pazienti ha dimostrato che la sintomatologia neurologica sia soggettiva che obiettiva cosi come le alterazioni elettrodiagnostiche continuano per anni in numerosi pazienti. Inoltre, dopo alcuni anni di osservazione, alcuni pazienti mostrano segni di interessamento del SNC come spasticità ed iperreflessia. In tutti i campioni di colle e di solventi utilizzati sia dai lavoratori a domicilio sia nelle fabbriche dove si sono verificati casi di polineurite, è stata trovata un'alta percentuale di esano commerciale

Clinical evaluation of 1,132 zirconia-based single crowns: A retrospective cohort study from the aiop clinical research group

Purpose: The aim of this retrospective cohort study was to gather the outcomes of zirconia single crowns made by 16 members of the Italian Academy of Prosthetic Dentistry (AIOP) over a time period of up to 5 years. Materials and Methods: A total of 398 patients treated in private practices with 1,132 zirconia-based single-crown restorations made on natural teeth from January 2005 to July 2010 were included. Three hundred forty-three anterior restorations (30.3%) and 789 posterior crowns (69.7%) were made with 16 types of zirconia, using primarily chamfer or knife-edge tooth preparation, and examined according to the esthetic, functional, and biologic criteria. To evaluate the relationship of parafunction with mechanical failure, patients with clenching or bruxism were not excluded from the study group. Results: The cumulative survival rate of all restorations was 98.1%, while the cumulative success rate was 94.3%. Functional criteria had the highest number of failures. The odds ratio (OR) for all restorations was calculated to clarify the relationship between patients who were subject/not subject to parafunctions and technical complications; the OR was 2.60. An association between parafunction and mechanical failure was found in patients with severe parafunction. Conclusions: Porcelain-veneered zirconia single crowns with chamfer and knife-edge preparations showed good clinical results over a period of up to 5 years. Technical complications were few and were limited primarily to patients with parafunction. © 2013 by Quintessence Publishing Co Inc

Clinical evaluation of zirconia-based restorations on implants: A retrospective cohort study from the AIOP clinical research group

Purpose: The aim of this retrospective cohort study was to evaluate the clinical performance of zirconia-based implant-supported single crowns and fixed dental prostheses (FDPs) made by 15 members of the Italian Academy of Prosthetic Dentistry (AIOP) over a time period of up to 5 years. Materials and Methods: One hundred thirtyone patients were treated with a total of 210 zirconia-based single crowns and FDPs on implants in anterior and posterior regions. A cohort group with parafunctional habits was compared with patients without parafunctional habits according to the esthetic, functional, and biologic United States Public Health Service criteria modified by the FDI World Dental Federation. Results: The estimated cumulative survival (ECS) and standard error (SE) of all restorations on implants was 91.95% \ub1 1.39%, and the estimated cumulative success (ECSs) and SE was 88.37% \ub1 1.72%. The ECS of single crowns and FDPs was 91.25% \ub1 3.69% and 95.23% \ub1 2.28%, respectively, and the estimated cumulative success rates were 88.84% \ub1 2.05% and 87.96% \ub1 3.16%, respectively. Mechanical failures, including four zirconia core fractures, three hairline cracks, four chippings, and five delaminations of the ceramic veneering material, were recorded during a 1-to 5-year observation period. The odds ratio of 3.39 (95% confidence interval: 1.18 to 9.73) showed a moderate association between parafunction and failure. Conclusions: Zirconiabased implant-supported restorations showed encouraging clinical results over a period of up to 5 years, but more clinical data are needed before these restorations can be considered a viable treatment alternative. Mechanical failures were primarily observed in patients with parafunctions