The Protruding Premaxilla: Is Our Current Approach the Right Answer?

BACKGROUND: In bilateral cleft patients, surgeons usually attempt to move the premaxillary segment posteriorly. These patients almost always develop maxillary hypoplasia, rendering our current algorithms questionable. The authors sought to determine if the lateral segments are in an appropriate position to serve as a target for movement of the premaxilla. METHODS: Bilateral cleft lip and palate patients treated at the University of Michigan from 1997 to 2015 were reviewed. Patients with skull radiographs or computed tomography (CT) imaging performed at age 3 or younger were included. Noncleft patients <3 years old seen in the craniofacial clinic during 2015 with negative imaging were included as comparative norms. Sella-nasion-A (SNA), sella-nasion-piriform (SNP), and sella-nasion-posterior nasal spine (SN-PNS) angles were determined in both the cleft patients and the comparative norms. Paired t tests assuming unequal variance were used to compare angles between normal and cleft patients. RESULTS: Eighty-six bilateral cleft patients were identified, and 16 had imaging. Only 7 patients had a CT or skull radiograph. Thirteen noncleft patients with negative imaging were included. The mean SNA angle was 100.8 in cleft patients and 86.1 in noncleft patients (P = 0.002). The mean SNP angle was 62.9 in cleft patients and 71.3 in noncleft patients (P = 0.02). The mean SN-PNS angle was 23.2 in cleft patients and 33.8 in noncleft patients (P = 0.005). CONCLUSIONS: Our results indicate that the maxilla is deficient early in life with posterior positioning of the lateral segments. Therefore, the lateral segments should not serve as a reference point when treating the premaxilla.

Establishing the diagnostic criteria for eruption disorders based on genetic and clinical data.

INTRODUCTION: Proper diagnosis and management of eruption disturbances remains challenging but is critical to a functional occlusion. The objective of this study was to establish definitive criteria to differentiate and diagnose eruption disorders, specifically primary failure of eruption (PFE) and ankylosis. METHODS: Sixty-four affected persons were placed into 3 cohorts: PFE diagnosed through confirmed PTH1R mutation (n = 11), PFE diagnosed based on clinical criteria (n = 47), and ankylosis diagnosed based on clinical criteria (n = 6). These groups were assessed to identify clinical features that differentiate PFE and ankylosis. RESULTS: Ninety-three percent of the subjects in the genetic and clinical PFE cohorts combined (n = 58) and 100% in the genetic PFE cohort had at least 1 infraoccluded first permanent molar. Additionally, a novel functional PTH1R mutation, 1092delG, was identified and linked to PFE in the deciduous dentition. CONCLUSIONS: An infraoccluded, supracrestal first molar is a hallmark of PFE, often involving both arches in the permanent or deciduous dentition, and with unilateral or bilateral affection, infraoccluded second premolar or second molar, and multiple affected adjacent teeth. Our results further suggest that PFE and ankylosis might be clinically indistinguishable without knowledge of prior trauma, treatment history, genetic information, or obliteration of the periodontal ligament space.