title: [Effect of inserted angle on the stability of loaded microscrews].
abstract: Objective:To evaluate the effect of different insertion angles on the osseointegration of loaded microscrews in beagle jaws.Methods:Forty-eight microscrews were inserted at four different angles (30°, 50°, 70° and 90°) into the interradicular zones between the mandibular first molar and third premolar in twelve beagles and the microscrews had been loaded with a force of 2 N immediately for 8 weeks. After microscrew-bone specimens fixed, the maximum output value (Fmax) of pull-out test was recorded and the histomorphological changes of hard tissue were observed. The bone-implant contact (BIC%) was quantitatively analyzed and the osseointegration of microscrew-bone interface was comprehensively evaluated.Results:Both Fmaxand BIC% values of microscrews were influenced by the insertion angles. The maximum value of Fmaxwas (385±23) N in the group with 50° angle, and the minimum value was (198±16) N in the group with 30° angle(P<0.05). The maximum value of BIC% was (59.1±6.0)% in the group with 70° angle, and the minimum value was (30.2±3.2)% in the group with 30° angle (P<0.05). Histomorphology observation revealed that in peri-screws region, the various degree of bone remodeling was found in different angle samples.Conclusions:The insertion angles (50°and 70°) were favorable to the stability of the microscrew.
authors.affiliation: State Key Laboratory of Oral Diseases, Sichuan University, Chengdu 610041, China (Present address: Department of Stomatology, 363 Hospital of China Aviation Industry, Chengdu 610041, China).
authors.forename: P
authors.initials: P
authors.lastname: Shao
authors.affiliation: Department of Orthodontics, Jinqin International Dental Clinic-Shuangnan Branch, Chengdu 610041, China.
authors.forename: Z R
authors.initials: ZR
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Oral Diseases, Sichuan University, Chengdu 610041, China.
authors.forename: L X
authors.initials: LX
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Oral Diseases, Sichuan University, Chengdu 610041, China.
authors.forename: Z H
authors.initials: ZH
authors.lastname: Zhao
mesh_terms: D000818:Animals; D001641:Bicuspid; D016723:Bone Remodeling; D001863:Bone Screws; D015921:Dental Implants; D006801:Humans; D007568:Jaw; D008963:Molar; D016348:Osseointegration
chemical_list: D015921:Dental Implants