The Effect of Magnification Loupes on Spontaneous Posture Change of Dental Students During Preclinical Restorative Training.

Scientific evidence validating the beneficial effect of loupes in preventing musculoskeletal disorders is very scarce. The aim of this study was to assess the impact of dental loupes on dental students' posture during a preclinical restorative dentistry course. Using a randomized crossover design, this study was conducted at the School of Dentistry, University of Nantes, France, in 2017. Forty students in their second year of dental study were randomly divided into two groups of 20 each: group A used loupes, whereas group B did not. The week after, students reversed configurations (each subject served as his or her own treatment and control group). Students were video-recorded during cavity preparation. Trunk, head and neck, and upper arm positions were analyzed using continuous scores based on the modified Posture Assessment Instrument. Additionally, cavities were rated, and students completed a questionnaire on their perceptions of the loupes. On a scale on which lower scores indicated better posture, the results showed significantly higher posture ergonomic scores per minute for students without loupes (146.3±6.64 points/min) than with loupes (123.2±6.77 points/min; p<0.05). The majority of the students (32/39, 82%) showed improvements in ergonomic postures with the use of loupes. Trunk, head, and neck were positively impacted by the use of loupes, but not the upper arms. Cavity preparations were not improved by the use of loupes. The questionnaire revealed negative aspects (pain and difficulty adapting) but underlined the perceived positive impact on posture. This study documented the ergonomic advantages and challenges of introducing magnification near the beginning of the dental training program.

Pilot Study of Laser Doppler Measurement of Flow Variability in the Microcirculation of the Palatal Mucosa.

Background. Histopathological alterations can arise when the denture-supporting mucosa experiences microbial and mechanical stress through the denture base and diagnosis of these diseases usually follows microvascular changes. Microcirculation measurement could allow for detection of such dysfunction and aid in the early diagnosis of palatal mucosa pathologies. Materials and Methods. We tested the sensitivity of laser Doppler for measuring the microcirculation of the palatal mucosa, assessing the median raphe (MR), Schroeder area (SA), and retroincisive papilla (RP). A Doppler PeriFlux 5000 System, containing a laser diode, was used. 54 healthy participants were recruited. We compare the measurements of PU (perfusion unit) using ANOVA test. Results. The numerical values for palatal mucosa blood flow differed significantly among the anatomical areas (p = 0.0167). The mean value of Schroeder area was 92.6 (SD: 38.4) and was significantly higher than the retroincisive papilla (51.9) (SD: 20.2) (p < 0.05), which in turn was higher than that of median raphe (31.9) (SD: 24.2) (p < 0.0001). Conclusion. Schroeder area appeared to have the greatest sensitivity, and vascular flow variability among individuals was also greatest in this region. We suggest that analysis of blood stream modification with laser Doppler of the palatal mucosa can help to detect onset signs of pathological alterations.

Clinical management of an atypical dental invagination.

Dental invagination (DI) is a tooth malformation that usually affects permanent teeth. Its precise etiology is still controversial and represents a clinical challenge as it can favor the development of carious lesion or periodontal inflammation. This paper presents a case of a 23-year-old Caucasian male, where an atypical buccal DI could not be completely diagnosed in the dens invaginatus category. Furthermore, other differential diagnoses could not be confirmed. The dental malformation was seen on a permanent maxillary first incisor and was associated with periodontal inflammation and attachment loss. Successful clinical management of this case consisted of surgical restorative treatment and regular follow-up, accompanied by thorough oral hygiene procedures.

A recall program for the outcome of conventional root canal treatment performed in a teaching hospital.

OBJECTIVES: This study investigated the long-term survival and the prognostic factors of endodontic treatments performed in a dental teaching hospital. The aim was to calculate the probabilities of success or failure according to the follow-up extent and to assess the time allowed for a complete periapical healing. MATERIALS AND METHODS: A cohort of 185 teeth were re-examined 1-4 years after treatment. The outcome was assessed on the basis of radiographic and clinical criteria as success, uncertain or failure. A survival analysis using the Cox model was used (i) to explore tooth survival and periapical healing over the time and (ii) to highlight the predictive factors of treatment outcome. RESULTS: After 2 years, the appearance of an apical periodontitis remained lower than 3.5%, whereas only 22.8% of periapical healed cases were notified. The prognosis factors are: (i) for teeth with initial healthy periapical conditions, coronal leakage (p = 0.002) with the higher risk of failure (RR = 19.77), absence of correspondence filling length/shaping = 0.026), type of teeth (p = 0.041) and (ii) for teeth with apical periodontitis, number of root canals (p = 0.000,91), correspondence filling length/shaping length (p = 0.017) and over-filling (p = 0.09). New periapical lesions or tooth loss were recorded after 2 years. Half of the successful cases of periapical healing were observed during the follow-up from 2-4 years. CONCLUSIONS: This longitudinal study shows that coronal leakage is responsible for late failure and that periapical healing is long to achieve. Therefore, endodontic treatments may require a follow-up of over 2 years.

Evaluation of the ability of laser Doppler flowmetry for the assessment of pulp vitality in general dental practice.

OBJECTIVES: In this study we investigated pulpal blood flow (PBF) values and moving blood cell velocity (MBCV) curves recorded by laser Doppler flowmetry (LDF) for pulpal vitality diagnosis in general dental practice and to compare MBCV curves to standard diagnostic tests in traumatology. STUDY DESIGN: LDF tests performed with the PeriFlux System 5000 were applied to vital and nonvital (endodontic treatment) teeth of healthy students (n = 52) and on 24 luxated teeth of patients. RESULTS: The PBF values were not reproducible and no statistically significant differences were observed between vital and nonvital teeth. MBCV curves in contrast could distinguish between the 2 tooth types. Tests on luxated teeth showed that while 62.5% of MBCV curves correlated with conventional vitality tests, only 12.5% of MBCV curves could help in vital diagnosis. CONCLUSION: When applied to luxated teeth, the MBCV curve appeared to be accurate when the standard vitality tests indicated a nonvital diagnosis.

Bioactive materials in endodontics.

Endodontic treatment in dentistry is a delicate procedure and many treatment attempts fail. Despite constant development of new root canal filling techniques, the clinician is confronted with both a complex root canal system and the use of filling materials that are harmful for periapical tissues. This paper evaluates reported studies on biomaterials used in endodontics, including calcium hydroxide, mineral trioxide aggregate, calcium phosphate ceramics and calcium phosphate cements. Special emphasis is made on promising new biomaterials, such as injectable bone substitute and injectable calcium phosphate cements. These materials, which combine biocompatibility, bioactivity and rheological properties, could be good alternatives in endodontics as root canal fillers. They could also be used as drug-delivery vehicles (e.g., for antibiotics and growth factors) or as scaffolds in pulp tissue engineering.

Progenitor cell isolation from muscle-derived cells based on adhesion properties.

Adult skeletal muscle possesses remarkable regenerative capacity that has conventionally been attributed to the satellite cells. These precursor cells were thought to contain distinct populations with varying myogenic potential. Recently, the identification of multipotent stem cells capable of new myofiber formation has expanded the general view on the muscle regenerative process. Here we examined the characteristics of turkey skeletal muscle-derived cell (MDC) populations that were separated according to their adhesion abilities. We sought to determine whether these abilities could be a potential tool for separating cells with different myogenic commitment. Using the preplate technique, we showed that MDCs display a wide range of adhesion ability, allowing us to isolate a marginal fraction with initial adhesion defect. Methodological investigations revealed that this defect represents an intrinsic and well-established biological feature for these cells. In vitro behavioral and morphological analyses showed that late adherent cells (LACs) share several primitive cell characteristics. Phenotypic assessment indicated that LACs contain early stage myogenic cells and immature progenitors of satellite cells, whereas early adherent cells consist mainly of fully committed precursors. Overall, our findings demonstrate for the first time in an avian model that differential MDC adhesion properties could be used to efficiently purify cells with varying myogenic commitment, including immature progenitor cells. This manuscript contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials.

Effects of Er:YAG and Nd:YAP laser irradiation on the surface roughness and free surface energy of enamel and dentin: an in vitro study.

Sixty-seven extracted molars were selected (134 samples). Dentin and enamel samples were prepared by buccal and lingual surface sectioning to expose a planar enamel or dentin surface. For the roughness study, 80 samples were randomly assigned to eight groups. Enamel and dentin surfaces were etched with a 37% phosphoric acid solution, irradiated with an Er:YAG laser or irradiated with a Nd:YAP laser. Samples were then observed in SEM using BSE. For the free-surface energy study, 54 samples received the same treatment as above. Two contact angle measurements were made on each surface using a goniometer. Data were analyzed by a non-parametric statistical test. Morphological changes on enamel and dentin were greater with acid-etch and Er:YAG laser than with Nd:YAP laser. Free surface energy was significantly greater with acid-etch or Er:YAG laser than with Nd:YAP laser (p < 0.001).