Relationship between the lingual frenulum and craniofacial morphology in adults
So-Jeong Jang, Bong-Kuen Cha, Peter Ngan, Dong-Soon Choi, Suk-Keun Lee, and Insan Jang. Am J Orthod Dentofacial Orthop 2011;139:e361-e367
I ntroduction: The purpose of this study was to determine the relationship between the length of the lingual frenulum and craniofacial morphology and test the hypothesis that skeletal Class III malocclusion is related to tongue-tie, in which the lingual frenulum is short and restricts the mobility of the tongue. Methods: The sample consisted of 50 skeletal Class I patients (0° < ANB angle < 4°), 50 skeletal Class II patients (ANB angle > 4°), and 50 skeletal Class III patients (ANB angle <0°). Direct and indirect measuring methods were used to quantify the length of the lingual frenulum. The median lingual frenulum length was measured directly with a lingual frenulum ruler. It was evaluated indirectly by measuring the differences between the maximum mouth opening with and without the tip of the tongue touching the incisive papilla. A lateral cephalogram was taken for each subject and a computerized cephalometric analysis was used to assess the cranial morphology. Analysis of variance (ANOVA) was used to compare the differences among the 3 groups. The Pearson correlation analysis was used to detect any relationship between the lingual frenulum length and cephalometric variables. Results: The median lingual frenulum length was significantly longer in the skeletal Class III subjects compared with the skeletal Class I and Class II subjects. The maximum opening of the mouth was significantly reduced in the skeletal Class III subjects compared with Class I and Class II subjects. Significant correlations were also found among the median lingual frenulum length, maximum mouth opening reduction, and the cephalometric variables such as the SNB and ANB angles, Wits appraisal, mandibular length, and the interincisal angle. Conclusions: The present study supports the hypothesis that skeletal Class III malocclusion is related to long median lingual frenulum or a tongue-tie tendency. Patients diagnosed with tongue-tie might have a tendency toward skeletal Class III malocclusion.
The effect of maxillary advancement and impaction on the upper airway after bimaxillary surgery to correct Class III malocclusion
Gundega Jakobsone, Arild Stenvik, and Lisen Espeland. Am J Orthod Dentofacial Orthop 2011;139:e369-e376
I ntroduction: The aim of this study was to evaluate the upper airway changes after simultaneous maxillary advancement/impaction and mandibular setback in skeletal Class III malocclusion. Methods: The subjects included 76 patients whose treatment included 1-piece LeFort I and bilateral sagittal split osteotomies. Lateral cephalograms were taken before surgery and 2 months and 3 years postoperatively. In order to analyze the effect of maxillary repositioning, the material was divided into subgroups according to whether the maxillary impaction and advancement were clinically significant (≥2 mm) or not. Results: Advancement of the maxilla with or without impaction resulted in a significant long-term increase ( P <0.001) in airway dimension at the nasopharyngeal level (13%–21% increase). At the oropharyngeal and retrolingual levels, a decrease took place but was significant ( P <0.05) only at the oropharyngeal level when the maxilla was not impacted. When the maxilla was not advanced, there was no significant change, except at the hypopharyngeal level (12% decrease) ( P <0.01). Conclusions: Clinically significant advancement (≥2 mm) of the maxilla significantly increased the airway dimension at the nasopharyngeal level and to some extent compensated for the effect of mandibular setback at the hypopharyngeal level.