Parkinson C E, Buschang P H, Behrents R G, Throckmorton G S, English J D
Department of Orthodontics, Baylor College of Dentistry, The Texas A&M University System Health Science Center, Dallas, TX 75246, USA.
Am J Orthod Dentofacial Orthop. 2001 Nov;120(5):503-12. doi: 10.1067/mod.2001.117202.
The purpose of this study was to assess the relationship between posterior occlusion and posttreatment changes in other occlusal variables. Pretreatment (T1), posttreatment (T2), and postretention (T3) records were obtained for 49 Class I (n = 23) and Class II (n = 26) extraction cases. Overbite, overjet, mandibular incisor irregularity, right and left molar deviations, midline deviation, and mandibular arch length were measured, and occlusal registrations were made of each set of dental casts. The proximity of posterior occlusal surfaces was measured as the contact or near-contact areas at or below 300 microm thickness, based on the optical densities of scanned images of the posterior occlusal registrations. The treatment changes for overbite, overjet, right and left molar deviation, and arch length were significantly greater in the Class II group, and the reductions in incisor irregularity were greater in the Class I group. No other class differences were found. Overbite, overjet, and incisor irregularity increased after treatment, and arch length continued to decrease, with no significant class differences. Contact and near-contact areas at or below 300 microm constituted 7% of the functional occlusal table for both classes at the end of treatment, having decreased significantly in both groups (21% in Class I and 29% in Class II) during treatment. Because contact and near-contact areas increased in some patients and decreased in others, there were no significant posttreatment changes. Negative correlations were found between contact and near-contact areas at T2 and changes in overjet from T2 to T3, and between contact and near-contact areas at T3 and changes in overbite from T2 to T3. No relationships were found between posterior contact and near-contact area and incisor irregularity. We concluded that (1) the area of actual and near contacts at or below 300 microm decreased significantly with treatment, indicating that, despite excellent treatment results by conventional standards, the proximity of posterior occlusal surfaces lessened; (2) the proximity of the posterior occlusal surfaces should not be expected to increase posttreatment; (3) posttreatment contact and near-contact areas may be factors in overbite and overjet stability; and (4) posttreatment contact and near-contact areas are not related to incisor irregularity.
本研究的目的是评估后牙咬合与其他咬合变量治疗后变化之间的关系。对49例Ⅰ类（n = 23）和Ⅱ类（n = 26）拔牙病例进行了治疗前（T1）、治疗后（T2）和保持后（T3）的记录。测量了覆合、覆盖、下颌切牙不齐、左右磨牙偏差、中线偏差和下颌牙弓长度，并对每组石膏模型进行了咬合记录。根据后牙咬合记录扫描图像的光学密度，将后牙咬合面的接近程度测量为厚度在300微米及以下的接触或近接触区域。Ⅱ类组覆合、覆盖、左右磨牙偏差和牙弓长度的治疗变化显著更大，Ⅰ类组切牙不齐的减少更大。未发现其他类别差异。治疗后覆合、覆盖和切牙不齐增加，牙弓长度继续减小，无显著类别差异。治疗结束时，300微米及以下的接触和近接触区域占两类功能性咬合面的7%，两组在治疗期间均显著减少（Ⅰ类为21%，Ⅱ类为29%）。由于接触和近接触区域在一些患者中增加而在另一些患者中减少，因此治疗后无显著变化。在T2时接触和近接触区域与从T2到T3的覆盖变化之间，以及在T3时接触和近接触区域与从T2到T3的覆合变化之间发现了负相关。后牙接触和近接触区域与切牙不齐之间未发现关系。我们得出结论：（1）治疗后300微米及以下的实际和近接触区域显著减少，表明尽管按照传统标准治疗效果良好，但后牙咬合面的接近程度降低；（2）不应期望治疗后后牙咬合面的接近程度增加；（3）治疗后接触和近接触区域可能是覆合和覆盖稳定性的因素；（4）治疗后接触和近接触区域与切牙不齐无关。
