Frazier-Bowers Sylvia A, Koehler Karen E, Ackerman James L, Proffit William R
Department of Orthodontics, School of Dentistry, University of North Carolina, Chapel Hill, NC 27599-7450, USA.
Am J Orthod Dentofacial Orthop. 2007 May;131(5):578.e1-11. doi: 10.1016/j.ajodo.2006.09.038.
Posterior open bite has several possible causes, including primary failure of eruption (PFE) that affects all teeth distal to the most mesial involved tooth, mechanical failure of eruption (MFE) (primarily ankylosis) that affects only the involved tooth or teeth, and soft-tissue interferences with eruption (other).
Radiographs and other clinical records for 97 cases of failure of posterior eruption submitted for consultation were analyzed to further characterize PFE and distinguish it from MFE.
Of the 97 cases, 38 were judged to be clear-cut PFE; 19 were diagnosed as MFE; 32 were classified as indeterminate failure because they were too young to be certain of the distinction between PFE and MFE; and 8 were placed in the "other" category. Two subtypes of PFE were observed. In type 1, eruption failure occurred at or near the same time for all teeth in an affected quadrant. In type 2, a gradient of the time of failure was present, so that some further development of the teeth posterior to the most mesial affected tooth was observed before eruption failure. A family history of eruption problems was noted in 10 of the 38 PFE subjects (26%), and a pedigree analysis was done for 4 families. This was consistent with autosomal dominant transmission.
The distinction between PFE and MFE is clinically important because it determines whether all posterior teeth, or only individual affected teeth, will not respond to orthodontic force. Certain diagnosis often requires progress radiographs so that the pattern of eruption of teeth distal to the most mesial affected tooth can be observed.
后牙开合有多种可能的原因，包括萌出原发性失败（PFE），它影响最靠前受累牙齿远中的所有牙齿；萌出机械性失败（MFE）（主要为粘连），它仅影响受累的一颗或多颗牙齿；以及软组织对萌出的干扰（其他）。
分析97例因后牙萌出失败前来咨询的患者的X线片及其他临床记录，以进一步明确PFE并将其与MFE区分开来。
97例患者中，38例被判定为明确的PFE；19例被诊断为MFE；32例被归类为不确定的失败，因为他们年龄太小，无法确定PFE和MFE之间的区别；8例被归为“其他”类别。观察到PFE的两种亚型。在1型中，受影响象限内所有牙齿的萌出失败发生在同一时间或接近同一时间。在2型中，存在失败时间的梯度，因此在萌出失败前，观察到最靠前受累牙齿后方的一些牙齿有进一步发育。38例PFE患者中有10例（26%）有萌出问题的家族史，并对4个家族进行了系谱分析。这与常染色体显性遗传一致。
PFE和MFE的区分在临床上很重要，因为它决定了所有后牙，还是仅个别受累牙齿，对正畸力无反应。某些诊断通常需要拍摄进展性X线片，以便观察最靠前受累牙齿远中牙齿的萌出模式。
