Second molar impaction associated with lip bumper therapy

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. .

INTRODUÇÃO: embora placas labioativas (PLAs) promovam um ganho clínico significativo no perímetro da arcada inferior em pacientes com dentição mista, ortodontistas são relutantes em usá-las devido a possibilidade de problemas eruptivos dos segundos molares. OBJETIVO: o presente estudo avaliou a impacção dos segundos molares associada ao uso das PLAs e como a impacção pôde ser resolvida. MÉTODOS: radiografias cefalométricas lateral e panorâmica de 67 pacientes (34 do sexo feminino e 33 do masculino) foram avaliadas antes (T1) e após (T2) o tratamento com PLAs, que durou aproximadamente 1,8 ± 0,9 anos. Expansão rápida do palato (ERP) foi usada na maxila no início do uso da PLA. Usando as radiografias panorâmicas, a impacção dos segundos molares inferiores foi avaliada relativamente à posição dos primeiros molares mandibulares. Os movimentos horizontais e verticais dos primeiros e segundos molares inferiores foram avaliados com base em sobreposições de estruturas estáveis da arcada inferior por meio das radiografias laterais. RESULTADOS: oito (11,9%) pacientes apresentaram impacção dos segundos molares mandibulares ao final do tratamento com PLA; dois pacientes tiveram de recorrer à intervenção cirúrgica para a correção da impacção, cinco tiveram a correção da impacção usando apenas espaçadores e um apresentou autocorreção da impacção. A coroa e o ápice do primeiro molar inferior migraram 1.3mm e 2,.3mm, respectivamente, para mesial. O segundo molar não mostrou movimento horizontal significativo. ...

Second molar impaction associated with lip bumper therapy.

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.

Adult Class III treatment using a J-hook headgear to the mandibular arch.

OBJECTIVE: To evaluate the treatment effects of high-pull J-hook headgear on the lower dental arch in nongrowing Class III patients. MATERIALS AND METHODS: Fourteen nongrowing Class III patients having an Angle Class III malocclusion and ANB angle of less than 1.0 degree, were treated with high-pull J-hook headgear to the lower arch. Using lateral cephalograms and plaster models obtained before treatment (T1), after active treatment (T2), and after the retention period (T3), the treatment outcome was analyzed. RESULTS: The incisal edge of the lower central incisor moved a mean of 1.2 mm to the lingual and 1.7 mm to the occlusal between T1 and T2. The axis of the lower incisor inclined 4.0 degrees to the lingual. The lower first molar cusp moved 1.5 mm to the distal and the root apex moved 2.0 mm to the mesial. Molar angulations were tipped 9.8 degrees to the distal. The occlusal plane showed 4.5 degrees counterclockwise rotation. The mean intermolar width increased 1.5 mm on average. Comparison of the records between T2 and T3 showed minimal changes. CONCLUSIONS: Distal movement of the lower dental arch using J-hook headgear was clearly demonstrated, confirming that the application of high-pull J-hook headgear to the lower arch was effective for improvement of the Class III occlusion.

Long-term profile changes in extraction and nonextraction patients.

INTRODUCTION: The purpose of this investigation was to determine the long-term differences in soft tissue profile changes between extraction and nonextraction patients who had been treated to the same incisor position and lip line. METHODS: Twenty extraction and 20 matched nonextraction patients, with posttreatment and long-term follow-up (average 15 years) records, were selected from a single private orthodontic practice. Posttreatment and long-term follow-up profile photos of the patients' nose, lip, and chin areas were evaluated by 105 orthodontists and 225 laypeople, who indicated their preferences and the amount of change they perceived among the 40 profiles. The patients had similar dental protrusion, soft tissue profile measurements, and ages at the posttreatment observation. RESULTS: No significant cephalometric differences between the extraction and nonextraction groups were found at long-term follow-up; both groups showed similar long-term changes. Significant (P < .05) differences were found between males and females at long-term follow-up; male lips became relatively more retrusive, and their profiles became flatter. Significant (P < .05) changes in the profiles were also perceived over time, but there was no relationship between the amount of change perceived and profile changes measured cephalometrically. There were also no significant (P < .05) differences in preferences between orthodontists and laypeople, between extraction and nonextraction patients, or between males and females. CONCLUSIONS: If extraction and nonextraction patients are treated to the same incisor position and lip line, the treatment modality does not affect long-term soft tissue profile changes. Furthermore, the amounts of change perceived by either orthodontists or laypeople were not related to the amount of change measured cephalometrically.