2020 Volume 12 Issue 2 Pages 158-167
Purpose: The study aimed to quantitatively and morphologically evaluate the gothic arch (following GoA) and tapping point (following TP) records at the time of new denture production, and to statistically analyze the number of adjustments of the new dentures and clarify the relationship.
Methods: Thirty-four records obtained by the GoA tracing method with tapping method were examined. Quantitative and morphological evaluations were conducted using the newly obtained GoA score. The results were divided into four groups by distance among the apex (following Ap)/TP and were statistically analyzed.
Results:
① Group A (0–0.8 mm) accounted for 32.4% (11 patients), group B (0.9–1.6 mm) 35.3% (12 patients), group C (1.7 mm) 23.5% (8 patients), and group D (TP only) 8.8% (3 patients). Ap and TP matched in 11.8% (in group A).
② There was no statistical difference in the front momentum or lateral momentum.
③ Within each group, there was no statistical difference in the spread angle from Ap.
④ The spread angle from TP increased with increasing Ap/TP distance.
⑤ The GoA score increased with increasing Ap/TP distance.
⑥ TP converged in 19 of 34 cases, but not in 15 cases. Compared with the cases where TP converged, the Ap/TP distance and GoA scores were significantly greater in cases where TP did not converge.
⑦ Regarding the number of denture adjustments, there was a statistically significant difference from group B, to group A and group C.
⑧ There was no relationship between the number of new denture adjustments and the convergence of TP.
Conclusion: Quantitative and morphological evaluations were performed on GoA and TP records, and the relationship between the number of denture adjustments and the convergence of TP was evaluated. When the distance among Ap/TP increased, there was no change in the functional limit of the mandibular movement from Ap. On the other hand, the movement from TP used the area of intermediate movement, therefore, the statistical variance increased. It was also found that the GoA score increased as the distance among Ap/TP increased, proving dysfunction of the mandibular movement. Regarding the number of denture adjustments, there was a statistically significant difference for group B, but clinically, there were only small differences with other groups. If the Ap/TP distance or GoA score increases, there may be an organic change in the temporomandibular joint or an inconsistency in the neuromuscular mechanism. However, the GoA tracing method with tapping method can diagnose whether or not the TP is appropriate for the mandibular position for the dentures.
