Efficiency of Class II subdivision malocclusion treatment with 3 and 4 premolar extractions

Asymmetric Extraction Decision in Orthodontics

During the treatment planning process, extraction decisions are crucial. As a therapy option, the extraction of teeth should be considered in instances where there is a lack of facial harmony and stability in the occlusion. Treatment aims, the kind of malocclusion, aesthetic considerations, and growth patterns are all factors that influence asymmetric extraction. For the most part, premolar extractions are required when there is a significant midline difference or an asymmetrical connection between the teeth. Premolars, which are the first teeth to erupt and occupy the posterior position in chewing, are more vulnerable to injury than other permanent teeth. The optimal time to remove a second molar is at the moment when the connection between the molars has normalized or when a major front cross-bite can be remedied.

A 3D mirroring and colormap asymmetry study of Class II subdivision patients

INTRODUCTION

Patients with Class II subdivision malocclusion present skeletal and dental asymmetries. The purpose of this study is to assess those asymmetries by 3D mirroring and colormap quantification.

METHODS

This study analyzed 50 initial CBCTs divided into two groups: Class I (control group) and Class II subdivision (study group) malocclusion patients. CBCTs were oriented and full skull was segmented generating a 3D model. The right side of the 3D models was mirrored, using a midsagittal plane as reference, resulting in a perfectly symmetric skull based on two right sides. Original and mirrored models were superimposed on the unchanged right half, and differences were quantified using a colormap. Eight regions of interest were assessed: gonion, mandibular front, maxillary front, zygomatic process, maxillary and mandibular canine and molar areas.

RESULTS

Statistically significant differences using the Mann-Whitney test were found in six of the eight evaluated areas when comparing the control to the study group. The maxillary skeletal areas did not show any difference between the groups.

CONCLUSIONS

Patients with Class II subdivision malocclusion show true skeletal and dental asymmetries when comparing right and left sides. The maxilla showed no significant skeletal asymmetry, but the maxillary teeth were positioned more mesially on the Class II side. The maxillary canine on the Class II side was also more bucally positioned. The mandible showed significant asymmetries with both skeletal and dental areas in the Class II side more distally and bucally positioned.

Outcomes of orthodontic treatment performed by individual orthodontists vs 2 orthodontists collaborating on treatment

INTRODUCTION

One factor that can affect treatment outcomes is the treatment provider, and this factor has not been extensively studied. This research aimed to evaluate orthodontic treatment quality, length, and efficiency when 2 orthodontists collaborated on treatment, compared with the treatment provided solely by either orthodontist.

METHODS

A total of 150 consecutively treated subjects were divided into 3 equal groups based on the treating clinician. Patients in group A were treated by orthodontist A, group B by orthodontist B, and group C by both orthodontists in collaboration. The Peer Assessment Rating (PAR), Index of Complexity, Outcome, and Need (ICON), American Board of Orthodontics-Discrepancy Index, and American Board of Orthodontics-Cast and Radiographic Evaluation were used to assess the pretreatment and posttreatment status. Patient age, gender, type of malocclusion, extraction treatment, orthognathic surgery, treatment length, number of visits, and treatment efficiency index were assessed.

RESULTS

Posttreatment PAR and ICON indices showed excellent results in all 3 groups. American Board of Orthodontics-Cast and Radiographic Evaluation was significantly higher in group C (25.3 points) than in group A (21.5 points) or group B (22.0 points) (P = 0.014). Patients in group A had significantly shorter treatment time (23 months) than those in either group B or C (26 months) (P = 0.011). Patients in group C required more appointments (27 visits) than those in either group A or B (23 and 25 visits, respectively). The treatment efficiency index showed no statistically significant difference among the 3 groups.

CONCLUSIONS

There was no difference in treatment quality among the 3 groups, as assessed by the PAR index and ICON. Jointly treated cases required 2 to 4 more visits and had higher American Board of Orthodontics-Cast and Radiograph Evaluation scores than those treated by either orthodontist. Complex cases required 6 to 7 more months when they were treated collaboratively.

Efficiency of class III malocclusion treatment with 2-premolar extraction and molar distalization protocols

INTRODUCTION

Different treatment protocols have been implemented for management of Class III malocclusion with aim of achieving ideal occlusal goals. The aim of current study was to compare the efficiency of Class III treatment with mandibular 2-premolar extraction and mandibular molar distalization protocol.

METHODS

This retrospective cross sectional study was conducted on pre-treatment and post-treatment dental casts of 60 orthodontic patients who had Class III malocclusion and were treated with a mandibular dentition distalization and mandibular 2-premolars extraction protocol. The study was conducted at orthodontic departments of Dental Section, Faisalabad Medical University/Punjab Medical College and de'Montmorency College of Dentistry, Pakistan. The sample was classified into 2 groups. Group A consisted of 30 patients (20 females, 10 males) (mean age, 18.02years) treated with distalization protocol and Group B consisted of 30 patients (18 females, 12 males) (mean age, 18.97years) treated with mandibular 2-premolars extraction protocol. To compare the efficiency of the treatment protocol in each group, the initial and final occlusal results were assessed on dental models using PAR index while treatment efficiency was assessed using a treatment efficiency index (TX). The groups were compared with t and Mann-Whitney tests.

RESULTS

There were no significant differences in the initial age, treatment time, treatment efficiency and any occlusal feature between the groups.

CONCLUSION

Treatment efficiency of Class III malocclusions with mandibular 2-premolar extractions or mandibular dentition distalization protocol is similar.

Dentoskeletal and soft tissue changes in class II subdivision treatment with asymmetric extraction protocols

Background

This study cephalometrically compared the dentoskeletal and soft tissue changes consequent to one and three-premolar extraction protocols of class II subdivision malocclusion treatment.

Methods

A sample of 126 lateral cephalometric radiographs from 63 patients was selected and divided into two groups. Group 1 consisted of 31 type 1 class II subdivision malocclusion patients treated with asymmetric extractions of two maxillary premolars and one mandibular premolar on the class I side, with an initial mean age of 13.58 years. Group 2 consisted of 32 type 2 class II subdivision malocclusion patients treated with asymmetric extraction of one maxillary first premolar on the class II side, with an initial mean age of 13.98 years. t test was used for intergroup comparison at the pre- and posttreatment stages and to compare the treatment changes.

Results

Group 1 had greater maxillomandibular sagittal discrepancy reduction and greater maxillary first molar extrusion. Group 2 had mandibular incisor labial inclination and protrusion, and group 1 had mandibular incisor lingual inclination and retraction. Maxillary molar asymmetry increased in group 2, while mandibular molar asymmetry increased in group 1.

Conclusions

The treatment changes produced by these two class II subdivision protocols are different to adequately satisfy the different needs for types 1 and 2 class II subdivision malocclusions.