IADR Abstract Archives
Measurement of Retention Forces of Mandibular Complete Dentures
Objectives: The size of mouth opening is known that retention force of mandibular complete denture is to be reduced empirically. However, a method to evaluate the retention force of mandibular complete dentures has not been established. Therefore, determining the size of mouth opening is necessary to appropriately measure retention force. This study aimed to determine the appropriate the size of mouth opening to measure retention forces and to clarify the effect of residual ridge forms on the retention forces of dentures.
Methods: Thirty-seven patients with edentulous mandible participated in this study. The edges of the left and right central incisors in the midline were loaded in a direction 45°downward to the occlusal plane. The retention force was considered as the force required to dislodge the denture. Mouth opening was specified at 1, 2, or 3 cm and was measured four times each. Retention forces were compared to the form of the molar residual ridge and the relative position of the anterior residual ridge.
Results: Retention force decreased with larger mouth opening sizes (p < 0.05). The smallest coefficient of variation was associated with 1 cm of mouth opening. As the ratio of the distance of the central incisor to the anterior residual ridge and the distance of the central incisor to the posterior denture border increased, retention force decreased (p < 0.01). No correlation was found between the shape of the posterior molar region of the residual ridge and retention force. However, the retention force decreased with decrease height of the posterior molar area (p < 0.01).
Conclusions: The results suggested that the mouth opening was regulated as 1 cm for appropriate measurement of mandibular denture retention. Additionally, the retention force of dentures is affected by the relative position of the anterior residual ridge.
Methods: Thirty-seven patients with edentulous mandible participated in this study. The edges of the left and right central incisors in the midline were loaded in a direction 45°downward to the occlusal plane. The retention force was considered as the force required to dislodge the denture. Mouth opening was specified at 1, 2, or 3 cm and was measured four times each. Retention forces were compared to the form of the molar residual ridge and the relative position of the anterior residual ridge.
Results: Retention force decreased with larger mouth opening sizes (p < 0.05). The smallest coefficient of variation was associated with 1 cm of mouth opening. As the ratio of the distance of the central incisor to the anterior residual ridge and the distance of the central incisor to the posterior denture border increased, retention force decreased (p < 0.01). No correlation was found between the shape of the posterior molar region of the residual ridge and retention force. However, the retention force decreased with decrease height of the posterior molar area (p < 0.01).
Conclusions: The results suggested that the mouth opening was regulated as 1 cm for appropriate measurement of mandibular denture retention. Additionally, the retention force of dentures is affected by the relative position of the anterior residual ridge.