Abstract
INTRODUCTION: Although lip bumpers (LBs) provide significant clinical gain of mandibular arch perimeter in mixed-dentition patients, orthodontists are reluctant to use them due to the possibility of permanent second molar eruptive disturbances. OBJECTIVE: The present study was conducted to assess second molar impaction associated with the use of LBs, and to investigate how they can be solved. MATERIAL AND METHODS: Lateral and panoramic radiographs of 67 patients (34 females and 33 males) were assessed prior (T1) and post-LB treatment (T2). LB therapy lasted for approximately 1.8 ± 0.9 years. Concomitant rapid palatal expansion (RPE) was performed in the maxilla at LB treatment onset. Impaction of mandibular second molars was assessed by means of panoramic radiographs in relation to the position of first mandibular molars. Horizontal and vertical movements of first and second molars were assessed cephalometrically on lateral cephalometric radiographs based on mandibular superimpositions. RESULTS: Eight (11.9%) patients had impacted second molars at the end of LB therapy. Two patients required surgical correction, whereas five required spacers and one patient was self-corrected. Mandibular first molar tip and apex migrated forward 1.3 mm and 2.3 mm, respectively. Second molar tip showed no statistically significant horizontal movement. CONCLUSION: Although LB therapy increased the risk of second molar impaction, impactions were, in most instances, easily solved.
Highlights
Lip bumpers (LBs) provide significant clinical gain of mandibular arch perimeter in mixeddentition patients, orthodontists are reluctant to use them due to the possibility of permanent second molar eruptive disturbances
Patients were selected based on the following criteria: » Lateral and panoramic radiographs had to be available at the start (T1) and end (T2) of lip bumpers (LBs) therapy. » Patients should have unerupted second permanent molars. » Patients should be treated under the same rapid palatal expansion (RPE)/LB therapy protocol
Diagnosis was based on the position of mandibular second molars at the end of lip bumper therapy, with consideration given to the position of first mandibular molars as well as the eruptive status of maxillary molars
Summary
Lip bumpers (LBs) provide significant clinical gain of mandibular arch perimeter in mixeddentition patients, orthodontists are reluctant to use them due to the possibility of permanent second molar eruptive disturbances. By maintaining leeway space and increasing arch width, LBs have proved an effective and relatively stable treatment approach.[3,4,5] LBs are inserted into buccal tubes cemented to first permanent molars, maintained in front of and away from lower anterior teeth and activated by lower lip pressure. Because they keep lower lip and buccal musculature away from mandibular teeth, LBs disrupt equilibrium which causes the crowns to move in buccal direction.[3,6,7,8] The therapeutic effects of LBs include increase in arch width, in premolar and molar regions, and an increase in arch depth associated with proclination of incisors and distal tipping of molars.[3,6,7,8,9]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
