Interdisciplinary treatment of an adult patient with old extraction sites

Prevention of bone dehiscence associated with orthodontic tooth movement by prophylactic injection of bone anabolic agents in mice

Although bone dehiscence may occur during orthodontic tooth movement into the narrow alveolar ridge, a non-invasive prevention method is yet to be fully established. We show for the first time prevention of bone dehiscence associated with orthodontic tooth movement by prophylactic injection of bone anabolic agents in mice. In this study, we established a bone dehiscence mouse model by applying force application and used the granular type of scaffold materials encapsulated with bone morphogenetic protein (BMP)-2 and OP3-4, the receptor activator of NF-κB ligand (RANKL)-binding peptide, for the prophylactic injection to the alveolar bone. In vivo micro-computed tomography revealed bone dehiscence with decreased buccal alveolar bone thickness and height after force application, whereas no bone dehiscence was observed with the prophylactic injection after force application, and alveolar bone thickness and height were kept at similar levels as those in the control group. Bone histomorphometry analyses revealed that both bone formation and resorption parameters were significantly higher in the injection with force application group than in the force application without the prophylactic injection group. These findings suggest that the prophylactic local delivery of bone anabolic reagents can prevent bone dehiscence with increased bone remodelling activity.

Alveolar bone loss and root resorption in mesialized second molars in mandibular first molar extraction cases as compared to contralateral non-extraction side in young adults: A retrospective cross-sectional study

INTRODUCTION

The alveolar bone loss (ABL) and external apical root resorption (EARR) depict the safety of mesialization of mandibular second molars into the extraction space of mandibular first molars. The aim of this study was to evaluate the ABL and EARR after closure of mandibular first molar extraction space by mesialization of second molar on extraction side (ES) as compared to the contralateral non-extraction side (NES).

MATERIAL AND METHODS

A retrospective cross-sectional study was carried out using the pre and posttreatment orthodontic records of young adults with complete set of permanent dentitions treated with extraction of unilateral mandibular first molar and non-extraction treatment on the contralateral side. All patients underwent mini-implant supported mesialization of second molar on ES. The ABL and EARR of second molar on ES and contralateral NES were measured on digital orthopantomograms. The ABL and EARR of second molars on ES and contralateral NES were compared using independent sample t-test.

RESULTS

A total of 36 subjects (14 males and 22 females) were included in the study. The mean treatment duration for molar mesialization was 28.75±8.05months. The mean crown and root movements of mandibular second molar on ES were 10.94±1.25mm and 9.04mm±1.14mm, as compared to 0.91±1.01mm and 0.77±0.83mm on contralateral NES, respectively. The mean ABL and EARR at mandibular second molar were found to be significantly greater on the ES than the contralateral NES (P<0.001 and<0.05, respectively). A total of seven patients (19.4%) experienced ABL≥1mm on ES as compared to none in the contralateral NES. EARR of>2mm of at least one root was found in seven patients (19.4%) in ES as compared to four (11%) in contralateral NES.

CONCLUSION

There was small but statistically significant difference in the ABL and EARR of mesialized mandibular second molar at first molar ES as compared to the contralateral NES. For majority of patients this difference was small but few isolated cases experienced severe ABL and EARR.

Movement of mandibular molar into edentulous alveolar ridge: A cone-beam computed tomography study

INTRODUCTION

The purpose of this study was to evaluate the thickness and height of buccal and lingual alveolar bone of mandibular teeth moved to edentulous areas with a remodeled alveolar ridge.

METHODS

The sample included 18 adult patients with unilateral or bilateral absence of mandibular permanent first molars with a mean age of 36.1 years before treatment. The mandibular hemiarches were divided into 3 groups: reopening group (15 hemiarches), closure group (12 hemiarches), and control group (9 hemiarches with no missing teeth). Cone-beam computed tomography scans with a 0.2-mm voxel size were performed 4 months after space closure or reopening. Cross sections 0.2 mm thick passing through the center of the mandibular permanent second molar and second premolar roots were used for measurements of the buccal and lingual bone plate thickness and level. Intergroup comparisons were performed with 1-way analysis of variance followed by Tukey tests (P <0.05).

RESULTS

No intergroup differences were found for the alveolar bone statuses of the mandibular second premolar. For the mandibular second molar, the closing group showed significantly smaller buccal and lingual crest levels compared with the control group.

CONCLUSIONS

Space closure of missing mandibular first molars caused slight buccal and lingual dehiscences at the mandibular second molar areas.

Interdisciplinary treatment of Class III malocclusion: a case report

The case report describes the multidisciplinary treatment of a 25-year-old male patient with a Class III malocclusion. Anterior and bilateral posterior crossbites were present. To correct the posterior crossbite a surgically assisted rapid maxillary expansion was performed. The significant three dimensional skeletal discrepancy was solved in a second phase with a surgical advancement of the maxilla. Functional and aesthetic occlusion in an improved facial profile was achieved with an interdisciplinary treatment that included orthodontic treatment, maxillofacial and periodontal surgery, and direct composite restorations.

Class III malocclusion with missing maxillary lateral incisors

A 23-year-old woman with a skeletal Class III relationship, a normal vertical jaw relationship, and missing maxillary lateral incisors was treated with bidimensional fixed edgewise appliance therapy combined with orthognathic surgery. A functional and esthetic occlusion in an improved facial profile was established at the end of the surgical and orthodontic treatment. Pretreatment, posttreatment, and long-term follow-up records for the patient are presented.