Do occlusal contact areas of maximum closing position during gum chewing and intercuspal position coincide?

ABSTRACT Objective The purpose of this study was to evaluate the effect of occlusal contact area for loading on the cuspal deflection and stress distribution in a first premolar restored with a high elastic modulus restorative material. Materials and methods The Rhinoceros 4.0 software was used for modeling the three-dimensional geometries of dental and periodontal structures and the inlay restoration. Thus, two different models, intact and restored teeth with three occlusal contact areas, 0.1, 0.5 and 0.75 mm2, on enamel at the occlusal surface of buccal and lingual cusps. Finite element analysis (FEA) was performed with the program ANSYS (Workbench 13.0), which generated a mesh with tetrahedral elements with greater refinement in the regions of interest, and was constrained at the bases of cortical and trabecular bone in all axis and loaded with 100 N normal to each contact area. Results To analysis of maximum principal stress, the smaller occlusal contact area showed greater compressive stress in region of load application for both the intact and inlay restored tooth. However, tensile stresses at the occlusal isthmus were similar for all three tested occlusal contact areas (60 MPa). To displacement of the cusps was higher for teeth with inlay (0.46- 0.48 mm). For intact teeth, the smaller contact area showed greater displacement (0.10 mm). For teeth with inlays, the displacement of the cusps were similar in all types of occlusal area. Conclusion Cuspal displacement was higher in the restored tooth when compared to the intact tooth, but there were no significant variations even with changes in the occlusal contact area. Relevance clinical Occlusal contacts have a great influence on the positioning of teeth being able to maintain the position and stability of the mandible. Axial loads would be able to generate more uniform stress at the root presenting a greater concentration of load application in the point and the occlusal surface. Thus, is necessary to analyze the relationship between these occlusal contacts as dental wear and subsequent occlusal interferences. How to cite this article Costa AKF, Xavier TA, Paes-Junior TJA, Andreatta-Filho OD, Borges ALS. Influence of Occlusal Contact Area on Cusp Deflection and Stress Distribution. J Contemp Dent Pract 2014;15(6):699-704.

Download Full-text

A Study on the Change of Occlusal Contacts and Occlusal Contact Areas with Lapse of Time after Occlusal Adjustment

Nihon Hotetsu Shika Gakkai Zasshi ◽

10.2186/jjps.24.137 ◽

1980 ◽

Vol 24 (2) ◽

pp. 137-153

Author(s):

Katsuumi Yoshinari

Keyword(s):

Occlusal Contact ◽

Contact Areas ◽

Occlusal Adjustment

Download Full-text

Effects of occlusal scheme on All-on-Four abutments, screws and prostheses: A three-dimensional finite element study

Journal of Oral Implantology ◽

10.1563/aaid-joi-d-19-00334 ◽

2020 ◽

Author(s):

Nurullah Türker ◽

Hümeyra Tercanlı Alkış ◽

Steven J Sadowsky ◽

Ulviye Şebnem Büyükkaplan

Keyword(s):

Finite Element ◽

Three Dimensional ◽

Good Prognosis ◽

Von Mises Stress ◽

Element Analysis ◽

Group Function ◽

Occlusal Contact ◽

Maximum Deformation ◽

Contact Points ◽

Von Mises

An ideal occlusal scheme plays an important role in a good prognosis of All-on-Four applications, as it does for other implant therapies, due to the potential impact of occlusal loads on implant prosthetic components. The aim of the present three-dimensional (3D) finite element analysis (FEA) study was to investigate the stresses on abutments, screws and prostheses that are generated by occlusal loads via different occlusal schemes in the All-on-Four concept. Three-dimensional models of the maxilla, mandible, implants, implant substructures and prostheses were designed according to the All-on-Four concept. Forces were applied from the occlusal contact points formed in maximum intercuspation and eccentric movements in canine guidance occlusion (CGO), group function occlusion (GFO) and lingualized occlusion (LO). The von Mises stress values for abutment and screws and deformation values for prostheses were obtained and results were evaluated comparatively. It was observed that the stresses on screws and abutments were more evenly distributed in GFO. Maximum deformation values for prosthesis were observed in the CFO model for lateral movement both in the maxilla and mandible. Within the limits of the present study, GFO may be suggested to reduce stresses on screws, abutments and prostheses in the All-on-Four concept.

Download Full-text

Effect of Chewing Gum on Bowel Motility in Women Undergoing Post-Operative Cesarean Section

International Journal of Innovative Research in Medical Science ◽

10.23958/ijirms/vol03-i06/04 ◽

2018 ◽

Vol 3 (06) ◽

Author(s):

Dr.Randa Mohammed AboBaker

Keyword(s):

Cesarean Section ◽

Hospital Stay ◽

Demographic Data ◽

Length Of Hospital Stay ◽

Chewing Gum ◽

Control Group ◽

Controlled Clinical Trial ◽

Bowel Motility ◽

Gum Chewing ◽

Significant Difference

Postoperative Ileus (POI) is one of the most common problems after obstetrics, gynecologic and abdominal surgeries. Sham feeding, such as gum chewing, accelerates the return of bowel function and the length of hospital stay. The present study aims to evaluate the effect of chewing gum on bowel motility in women undergoing post-operative cesarean section. Intervention study was used at the Postpartum Department of Maternity and Children Hospital, KSA. A randomized controlled clinical trial research design. Through a convenience technique, 80 post Caesarian Section (CS) women were included in the study. Data were collected through three tools: Tool (I): Socio-demographic data and reproductive history interview schedule. Tool (II): Postoperative Assessment Sheet. Tool (III): Outcomes of gum chewing and the length of hospital stay. Method: subjects were assigned randomly into two groups of (40) the experimental and (40) the control. Subjects in the study group were asked to chew two pieces of sugarless gum for 30 min/three times daily in the morning, noon, and evening immediately after recovery from anesthesia and in Postpartum Department; while subjects in the control group followed the hospital routine care. Each woman in both groups was tested abdominally using a stethoscope to auscultate the bowel sounds and asked to report immediately the time of either passing flatus or stool. Results: illustrated that a highly statistically significant difference was observed between the two groups concerning their gum chewing outcomes. Where, P = 0.000. The study concluded that gum chewing is safe, well tolerated and appears to be effective in reducing the incidence and consequences of POI following CS.

Download Full-text

Inducing Frictional Force to Enhance the Transient Response in Beams

Al-Nahrain Journal for Engineering Sciences ◽

10.29194/njes.22020088 ◽

2019 ◽

Vol 22 (2) ◽

pp. 88-93

Author(s):

Hamed Khanger Mina ◽

Waleed K. Al-Ashtrai

Keyword(s):

Numerical Analysis ◽

Transient Response ◽

Frictional Force ◽

Damping Ratio ◽

Experimental Results ◽

Damping Capacity ◽

Tightening Force ◽

Contact Areas ◽

Good Agreement ◽

Ansys Workbench

This paper studies the effect of contact areas on the transient response of mechanical structures. Precisely, it investigates replacing the ordinary beam of a structure by two beams of half the thickness, which are joined by bolts. The response of these beams is controlled by adjusting the tightening of the connecting bolts and hence changing the magnitude of the induced frictional force between the two beams which affect the beams damping capacity. A cantilever of two beams joined together by bolts has been investigated numerically and experimentally. The numerical analysis was performed using ANSYS-Workbench version 17.2. A good agreement between the numerical and experimental results has been obtained. In general, results showed that the two beams vibrate independently when the bolts were loosed and the structure stiffness is about 20 N/m and the damping ratio is about 0.008. With increasing the bolts tightening, the stiffness and the damping ratio of the structure were also increased till they reach their maximum values when the tightening force equals to 8330 N, where the structure now has stiffness equals to 88 N/m and the damping ratio is about 0.062. Beyond this force value, increasing the bolts tightening has no effect on stiffness of the structure while the damping ratio is decreased until it returned to 0.008 when the bolts tightening becomes immense and the beams behave as one beam of double thickness.

Download Full-text