Rationale: Class II Division 1 malocclusion is characterized by upper anterior teeth protrusion resulting in upper lip protrusion and convex facial profile, which are considered esthetically unfavorable. Treatment of class II malocclusion due to maxillary protrusion can be done with bilateral maxillary first premolar extraction followed by en-masse retraction of upper anterior teeth using mini-implants placed at infrazygomatic or interradicular sites.
Aims and Objectives: To evaluate the treatment changes achieved in class II division 1 malocclusion during en- masse retraction of upper anterior teeth using mini-implants placed at infrazygomatic crest versus interradicular sites.
To compare patients' and orthodontist's perceptions of treatment being done in both the groups.
Method of study: Treatment will be initiated by bilateral maxillary 1st premolar extraction followed by bonding 0.022" slot MBT preadjusted edgewise appliance. Maxillary arch will be stabilized with the help of 0.019"×0.025" stainless steel wire and then randomized allocation of the patients into 2 groups-G1 and G2 will be done. G1 will receive infrazygomatic crest mini-implants bilaterally and G2 will receive bilateral interradicular mini-implants. Hooks will be soldered on archwire used for stabilizing dentition. Ni-Ti closed coil spring will be used to apply force.
Non growing patients
Bilateral Class II molar relationship at pre-treatment.
All permanent teeth upto the second molars should be present.
No or minor crowding in the maxillary arch.
Subjects with a history of fixed orthodontic treatment.
Crossbite
Vertical growth pattern
Any systemic disease affecting bone and general growth
Parallel
retraction of anterior teeth using mini implants placed at infrazygomatic crest.
Procedure/Surgeryundergo bilateral extraction of maxillary first premolars before initial leveling and alignment followed by retraction of anterior teeth using mini implants placed at infrazygomatic crest.
retraction of anterior teeth using mini implants placed at interradicular sites.
Procedure/Surgerybilateral extraction of maxillary first premolars before initial leveling and alignment followed by retraction of anterior teeth using mini implants placed at interradicular sites.
skeletal and dental cephalometric variables
Comparison of pretreatment and post 6 month evaluation of skeletal and dental cephalometric variables between the two groups Skeletal cephalometric variables 1. SNA: SN to NA angle 2. A-NPerp: linear distance from A-point to nasion-perpendicular(a line perpendicular to Frankfort plane, through nasion) 3. SNB: SN to NB angle 4. SND: SN to ND angle 5. LAFH (lower anterior face height): distance from anterior nasal spine to menton. Dental cephalometric variables 1. Mx1.NA: maxillary incisor long axis to NA angle 2. Mx1-NA: distance between the maxillary central incisor edge and the NA line 3. Mx1-VRL: distance from the maxillary central incisor edge to VRL (vertical reference line passing through sella and perpendicular to horizontal line constructed by reducing 7° from SN line) 4. Mx6-VRL: distance from maxillary first molar mesial cusp to VRL 5. Md1.NB: mandibular incisor long axis to NB angle 6. Md1-NB: distance between the mandibular central incisor edge and the NB line.
soft tissue variables between the two groups
Comparison of pretreatment and post 6 month evaluation of soft tissue variables between the two groups 1. LL-E plane: distance from the lower lip to the esthetic plane of Ricketts (line from Pg= to Pr) 2. UL-E plane: distance from the upper lip to the esthetic plane of Ricketts 3. UL-S line: distance from the upper lip to Steiner's S line (line from Pg= to Cl) 4. LL-S line: distance from the lower lip to Steiner's S line 5. UL-SnPg: distance from the upper lip to the subnasale-soft-tissue pogonion plane (line from Sn to Pg) 6. LL-SnPg: distance from the lower lip to the subnasale-soft-tissue pogonion plane 7. H.NB: H line (tangent to Pg= and UL) to NB line angle 8. H-Pr: distance between H line and the most anterior point on the nose 9. Nasolabial angle: Cl.Sn.UL angle
patient attitude and pain perception
Questionnaire for evaluating patient attitude and pain perception for orthodontic treatment 1. Did your doctor in terms of pain/discomfort and its impact explain you properly about the appliance on daily activity? Yes No 2. Did you feel embarrassment/discomfort in front of others while talking? (a) Not at all (b) a little (c) a lot (d) does not worry me 3. Did you feel embarrassment/discomfort in front of other while eating? (a) Not at all (b) a little (c) a lot (d) does not worry me 4. Did you get any soft tissue lacerations? (a) Receiving of the appliance (b) Using the appliance (c) Breakage of appliance (d) None of the above 5. Did you ask the doctor to remove the appliance because you felt it is too hard to have it in your mouth for the long time? Yes No
orthodontic perception
Questionare for orthodontic perception during treatment 1. Handling complexity of mini-implant attachment a)very easy b)easy c)somewhat easy d)difficult e)very difficult 2. Mobility a)no b)mild c)moderate that treatment discontinued for sometime d)severe that treatment stopped 3. soft tissue ulcer 4. fracture 5. undesirable position 6. infection
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