Volumetric variation of peri-implant soft tissues in convergent collar implants and crowns using the biologically oriented preparation technique (BOPT).

BACKGROUND: To evaluate the changes in the peri-implant soft tissues of convergent collar implants with biologically oriented preparation technique (BOPT) crowns, 10 months after loading. MATERIAL AND METHODS: A pilot study was carried out from January 2016 to October 2017 involving 14 patients with one or two implants in the posterior mandibular sector. A total of 32 convergent collar implants were placed using a non-submerged protocol. Three months later the provisional cemented crowns were fitted using the BOPT approach with the finish line 1-1.5 mm below the gingival margin, simulating coronal emergence of a natural tooth. The soft tissue changes were measured with an intraoral scanner at two different timepoints: a) on the day of provisionalization, before prosthetic loading; and b) 10 months later without the provisional prosthesis. The STL files were superimposed and the soft tissue changes were recorded using a color scale with measurement of the volumetric changes in mm3. RESULTS: A mean increase in peri-implant mucosal volume of 64.7 mm3 was observed in 29 implants. The zones with the greatest increase in soft tissue volume were the papillae of implants with adjacent teeth and the peri-implant buccal margin. Three implants showed a mean decrease in soft tissue volume of -25.1 mm3. CONCLUSIONS: The fitting and design of crowns using the biologically oriented preparation technique (BOPT) over convergent collar implants affords a significant increase in peri-implant soft tissue volume both at the level of the papillae and in the buccal margin.

Wrong postural hygiene and ergonomics in dental students of the University of Valencia (Spain) (part I).

INTRODUCTION: Failure to adopt a correct working posture can lead to occupational diseases. OBJECTIVES: Evaluate knowledge in relation to ergonomics about BHOP concept and its application to routine clinical practice amongst undergraduate and postgraduate dental students in the University of Valencia (Valencia, Spain). MATERIAL AND METHODS: A study based on interviews of undergraduate and postgraduate dental students in the University of Valencia (Valencia, Spain) was carried out. The information from a total of 336 interviews was used for the statistical analysis, differentiating according to gender and academic year: knowledge of ergonomics, pain prevalence and antecedents, assessment of the possible necessity for improved training in ergonomics, and evaluation of postural hygiene. RESULTS: Only 28.6% of the students were found to sit correctly in the dentist chair. Furthermore, in the opinion of the students, very few subjects during the career afforded adequate teaching in relation to ergonomics and working posture. The analysis of postural hygiene showed great variability. There were no significant differences in posture between males and females, although some incorrect postures appeared to be associated with the academic year (P<.05). However, no significant improvements in postural hygiene were noted on progressing from one academic year to the next. CONCLUSIONS: The students in our study were not familiar with the principles of ergonomics and did not sit correctly in the dentist chair. Improved training in this field is required in dental school.

Estudio in vitro de las fuerzas de retención de los retenedores directos de resina acetálica frente a los metálicos en prótesis parcial removible / Measurement in vitro of the retention force of the acetalic clasp versus metalic clasp in removable partial prosthesis

Se presenta un estudio experimental in vitro en el que se compara la retención que ofrecen los retenedores circunferenciales tipo Ackers de resina acetálica con los de cromo-cobalto. Se realizan para ello 6 coronas de cromo-níquel, 3 con forma de canino superior y 3 con forma de primer premolar superior y cada una de ellas con un grado diferente de retención (0.25, 0.50 y 0.75 mm). Sobre cada una de ellas se confecciona un retenedor de resina acetálica y uno de cromo-cobalto, siendo testados por una máquina Instron. Los resultados confirman que los retenedores de cromo-cobalto son más retentivos, y que los acetálicos ofrecen una retención suficiente para cumplir su cometido (AU)

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[Diagnosis of compound odontoma. Apropos of 2 cases]. / Diagnóstico del odontoma compuesto. A propósito de dos casos clínicos.

We have a bibliografical study of the composite odontomas from the diagnostical point of view. We will present two clinical cases. Once the medical revision is done, and the tumor is localized, we analyze lesions associated with the tumor and compare the diagnostic from the clinical point of view as well as the radiografical point of view.