Quality of cross-infection control in dental laboratories. A critical systematic review.

PURPOSE: To identify reported practices for cross-infection control in dental laboratories and to quantify the importance of the flaws encountered. DATA SOURCES: Systematic search (cross-infection AND dental laboratory) at EMBASE, PubMed, SciELO and Scopus databases. STUDY SELECTION: Papers reporting on cross-sectional studies providing original data about cross-infection knowledge, practices and attitudes of dental technicians. Papers reporting on a single laboratory or institution were excluded. DATA EXTRACTION: Data extraction was undertaken independently by three reviewers using a purpose made form. The outcome of this study was analyzed in five aspects, namely process organization, disinfection, working environment, use of individual protective equipment and vaccination policy. RESULTS OF DATA SYNTHESIS: The systematic search output was 1651 references and 11 papers were finally selected. Flaws were more frequently identified in terms of vaccination policy, biological safety of the working environment and use of individual protective equipment (100%). Slightly better results were found in terms of organization of the cross-infection control process (89.47%) and disinfection practices (85.71%). The application of the formula for disclosing the relative importance of the flaws identified in the literature prioritizes the need for interventions aimed at improving the organization of the cross-infection control procedures, followed by training in item disinfection. The control of the working environment together with the use of individual protective equipments rank closely in importance, followed by the existence of a vaccination policy. CONCLUSIONS: Sub-standard cross-contamination practices seem to be a common finding in dental laboratories, which may well compromise the quality of certain dental treatments.

Control de la infección cruzada en los laboratorios de prótesis dental de Galicia / Control of cross-contamination in dental prostheses laboratories in Galicia

Fundamento: El laboratorio dental es una fuente potencial de contaminación cruzada. Este trabajo busca evaluar su control en Galicia. Material y métodos: Entrevistas telefónicas aleatorias y voluntarias hasta completar 149 cuestionarios. Las variables se describen mediante porcentajes o medias y desviaciones típicas. Se realiza análisis bivariante empleando ji cuadrado. Resultados: Participaron mayoritariamente varones (68,5%), de mediana edad (media=45,7; DE=9,8) con 20,8 (DE=10,5) años de ejercicio en laboratorios urbanos medianos (58,4%), que cuentan mayoritariamente con protocolo escrito (57,7%) y que identifican mayor riesgo al recibir trabajos (80,6%). El 55,0% (significativamente hombres de mayor edad) no asegura la desinfección de los trabajos. La mayoría usa guantes (62,4%), sobre todo jóvenes en laboratorios grandes. Un 55,7% está vacunado frente a hepatitis B. Una minoría (22,0%) ha recibido formación en control de contaminación cruzada. Conclusiones: Las prácticas de control de contaminación cruzada se encuentran por debajo de los estándares recomendados, con un importante déficit de formación y protocolos

Background: Dental laboratories are a potential source of cross-contamination. This study aims to assess its control in Galicia. Methods: Voluntary random telephone interviews resulted in 149 completed questionnaires. The variables are described by percentages or means and standar deviations. A bivariate analysis was undertaken using the Chi square test. Results: Participants were mostly middle-age (mean=45.7, SD=9.8) males (68.5%) with 20.8 (SD=10.5) years of professional experience in middle-size urban (58.4%) laboratories, who identified a higher risk when receiving items from the clinic (80.6%). Most technicians (57.7%) have a written protocol. Many (55.0%), significantly older males, do not check for item disinfection. Most technicians use gloves (62.4%) particularly younger staff at larger laboratories. Fifty-five point seven percent had been vaccinated against hepatitis B. Only 22.0% of technicians reported receiving training in cross-contamination control. Conclusions: Identified cross-infection control practices are below standards, and lack of training and protocols are a matter for concern

[Control of cross-contamination in dental prostheses laboratories in Galicia]. / Control de la infección cruzada en los laboratorios de prótesis dental de Galicia.

BACKGROUND: Dental laboratories are a potential source of cross-contamination. This study aims to assess its control in Galicia. METHODS: Voluntary random telephone interviews resulted in 149 completed questionnaires. The variables are described by percentages or means and standard deviations. A bivariate analysis was undertaken using the Chi square test. RESULTS: Participants were mostly middle-age (mean=45.7, SD=9.8) males (68.5%) with 20.8 (SD=10.5) years of professional experience in middle-size urban (58.4%) laboratories, who identified a higher risk when receiving items from the clinic (80.6%). Most technicians (57.7%) have a written protocol. Many (55.0%), significantly older males, do not check for item disinfection. Most technicians use gloves (62.4%) particularly younger staff at larger laboratories. Fifty-five point seven percent had been vaccinated against hepatitis B. Only 22.0% of technicians reported receiving training in cross-contamination control. CONCLUSIONS: Identified cross-infection control practices are below standards, and lack of training and protocols are a matter for concern.

Approach towards the porous fibrous structure of the periodontal ligament using micro-computerized tomography and finite element analysis.

The periodontal ligament (PDL) is a porous and fibrous soft tissue situated around the tooth, which plays a key role in the transmission of loads from the tooth to the alveolar bone of the mandible. Although several studies have tried to characterize its mechanical properties, the behaviour of this tissue is not clear yet. In this study, a new simulation methodology based on a material model which considers the contribution of porous and fibrous structure with different material model formulations depending on the effort direction is proposed. The defined material model was characterized by a non-linear approximation of the porous fibrous matrix to experimental results obtained from samples of similar species and was validated by rigorous test simulations under tensile and compressive loads. The global PDL response was also validated using the parameters of the characterization in a finite element model of full human canine tooth obtained by micro-tomography. The results suggest that the porous contribution has high influence during compression because the bulk modulus of the material depends on the ability of interstitial fluid to drain. On the other hand, the collagen fibres running along the load direction are the main responsible of the ligament stiffness during tensile efforts. Thus, a material model with distinct responses depending of the load direction is proposed. Furthermore, the results suggest the importance of considering 3D finite element models based of the real morphology of human PDL for representing the irregular stress distribution caused by the coupling of complex material models and irregular morphologies.

Use of a Copper Band to Make Resin Cores in Endodontically Treated Teeth Lacking Coronal Structure.

This article describes the use of a copper band as a matrix to build up resin cores in endodontically treated teeth that have a partially subgingival margin. The copper band is adjusted to the contour of the remaining dental structure and extends beyond the margins to ensure complete isolation in order to provide a matrix to fabricate a core.

Changes in EMG activity during clenching in chronic pain patients with unilateral temporomandibular disorders.

The study assessed the differences in electromyographic (EMG) activity recorded during clenching in women with chronic unilateral temporomandibular disorders (TMDs) as compared to control subjects. Seventy-five full dentate, normo-occlusion, right-handed, similarly aged female subjects were recruited. Twenty five subjects presented with right side TMD, 25 presented with left side TMD and 25 pain-free control subjects participated. Using integrated surface EMG over a 1 s contraction, the anterior temporalis and masseter muscles were evaluated bilaterally while subjects performed maximum voluntary clenching. Lower EMG activation was observed in patients with TMD as compared to control subjects (temporalis: 195.74+/-18.57 vs. 275.74+/-22.11, P=0.011; masseters: 151.09+/-17.37 vs. 283.29+/-31.87, P<0.001). An asymmetry index (SAI) was calculated to determine ratios of right to left sided activation. Patients with right-sided TMD demonstrated preferential use of their left-sided muscles (SAI -5.35+/-4.02) whereas patients with left-sided TMD demonstrated preferential use of their right-sided muscles (SAI 6.95+/-2.82), (P=0.016). This unilateral reduction in temporalis and masseter activity could be considered as a specific protective functional adaptation of the neuromuscular system due to nociceptive input. The asymmetry index (SAI) may be a useful measure in discriminating patients with right vs. left-sided TMD.