Mini-implants Used In The Treatment Of A Patient With Combined Skeletal Class Ⅲ And Dental Open Bite Malocclusion

Background:Class Ⅲ-Anterior Open Bite(AOB)malocclusion is not a simple malocclusion to treat.To obtain the best results;malocclusion aetiology,severity,patient’s opinion and expectations have to be clarified,and then a proper treatment method should be selected.In non-growing patient,camouflage therapy is done for mild-moderate cases and orthognathic approach for severe cases.Combined orthodontic/surgical therapy has long term stability than camouflage alone.Several techniques are used to camouflage skeletal class Ⅲ-AOB malocclusion.The factors determining method of camouflage treatment include anchorage strategy,compliance plus clinician’s skills and preference.Various camouflage treatment techniques for true Class Ⅲ-AOB have been proposed.These include;multi-loop edgewise arch-wire(MEAW)therapy,Tweed-Merrifield technique and straight wire fixed appliances.Acceptable results have been reported;however these methods have are some drawbacks.In MEAW therapy,wire bending requires intense training skills.Tweed technique depends on patient’s compliance for success of treatment.Newer improved techniques like skeletal anchorage and self-ligation are now available.Objective:The aim of the study was to explore the application of self-ligating brackets and class Ⅲ elastics hooked to the upper posterior mini-implants in the treatment of a patient with class Ⅲ skeletal malocclusion and dental anterior open bite.Methods:The patient used for the study was a healthy male aged 16.He presented to Aosuo Stomatology Hospital with a complaint of space between his upper and lower teeth.The diagnosis of the patient was concluded to be angle class Ⅲ on a skeletal class Ⅲ base,the malocclusion was complicated by;dental anterior open bite,lower lip protrusion,proclined upper incisors,anterior and right unilateral posterior crossbites,one millimeter shift of lower midline to the left,mild anterior spacing in both jaws and a tongue thrust habit.The causes of patient’s malocclusion were hereditary factors(as evidenced by his father’s facial features)and tongue thrust habit.Maxillary wisdom teeth were removed.Damon clear brackets together with class Ⅲ elastics connected to the posterior maxillary miniscrews were used.Crossbite elastics and upper archwire expansion was done for correction of the right posterior crossbites.Tongue exercises and oral hygiene methods were reinforced regularly.Upper and lower Hawley’s retainers were prescribed at the end of active treatment.Results:The patient’s facial profile was maintained as indicated by normal Z angle of 73°.Reduction of lower lip protrusion also occurred.Normal overbite and overjet were accomplished.The upper incisor flaring was slightly reduced after treatment.1-NA changed from 400°to 38°.The mandibular incisors were retracted as indicated by the lower incisor-mandibular angle which changed from 92.5° to 83°.There was extrusion of upper and lower incisors which helped to correct the open bite.The vertical pattern was maintained.The molar extrusion in both arches was minimal.Conclusion:Self-ligating brackets and class III elastics hooked to the upper posterior mini-implants were efficient in the treatment of this patient with skeletal Class III and anterior open bite malocclusion.