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王涛 陈杰 梁珊珊（青岛大学 山东 青岛 266003）
【中图分类号】 R2 【文献标号】 A 【文章编号】 2095-9753（2016）4-0249-02Wang Tao, Chen Jie and Liang Shanshan(qingdao university , Qingdao, Shandong, 266003)【 Abstract 】 Objective: To study the clinical application of mini-screw implant as anchorage for extruded molar intrusion.Methods: 10 patients with over-erupted maxillary molars treated in Orthodontics Department of the Affiliated Hospital of QingdaoUniversity from October 2013 to April 2015 were selected, including 10 patients with maxillary molar elongation caused by theuntimely repair of long-termed missing of mandibular molar. All patients used mini-screw implant as anchorage and used elastic chainon extruded molar. Panoramic radiographs and lateral cephalometric radiolographs were taken before and after the treatment. Results:10 patients successfully completed treatment; the intruded tooth root didn’t appear obvious absorption and the missing teeth wererepaired. The average extruded molar intrusion length of the 10 patients was( 2.90±0.75)mm and the average treatment time was(7.50±0.45) months. Conclusions: for the specific situation of patients with extruded molar intrusion, the mini-screw implant andreasonable treatment force can effectively intrude extruded molar. Mini-screw implant anchorage has strong clinical maneuverabilityand has no serious complications, so it is worthy of clinical reference and promotion.【 Keywords】: Mini-screw Implant; Intrusion; Extruded Molar
If people suffer molar missing caused by tooth decay or gum diseaseand fail to timely repair it, they will suffer extruded molar and insufficientvertical repair space. Such symptom is common in Orthodontic clinicaltreatment. For such patients, the whole treatment idea is to intrudeextruded molar. People used to treat such symptom with a fixed ormobile appliance, which only could provide weak anchorage, tooklong course of treatment and tended to bring oral cavity discomfort topatients. Thus, it is very difficult to guarantee the treatment effect. Li Jun[1] points that traditional method of mini-screw implant as anchoragehas more significant orthodontic effect and is more comfortable forpatients. The wide application of mini-screw implant as anchorage makesabsolute molar intrusion possible. Mini-screw implant as anchorage formaxillary extruded molar was used in the cases, and space was createdfor mandibular false tooth repairing. The specific process was reported asfollows.1. Data and Methods1.1 Research object10 patients with over-erupted maxillary molars treated inOrthodontics Department of the Affiliated Hospital of QingdaoUniversity from October 2013 to March 2015 were selected, including10 patients with maxillary molar elongation caused by the untimelyrepair of long-termed missing of mandibular molar. Eight cases wereof the symptom of maxillary first extruded molar due to the missing ofmandibular first molar; 2 cases were of the symptom of maxillary first andsecond extruded molars due to the missing of unilateral mandibular firstand second molars. There were 7 female cases and 3 male cases, at the ageof 42~55, with the average age of 48. Besides, the teeth that needed to beintruded were free from tooth body and periodontal diseases.1.2 DataSelf-tapping type mini-screw implant with the diameter of 1.4mmand length of 8.0mm produced by the U.S. ORMCO was used.1.3 Therapeutic methodPanoramic radiographs, lateral cephalometric radiolographs andperiapical radiography of extruded molars of each patient were takenbefore and after the treatment. Periodontal bone density was measuredwith computer software. The root morphology of extruded molars wasobserved and the position relationship between extruded molar andadjacent tooth root was noted. Patients’ complete mouth model wastaken before and after treatment; the pictures inside the mouth weretaken.1.3.1 Position and method of mini-screw implant as anchorageThe periodontal bone density, the space between tooth root andadjacent tooth root of extruded molar to be intruded should be carefullyobserved and measured before the operation so as to avoid mini-screwimplant from loosening and the risk of injury to the tooth root. Whenthe maxillary first molar was intruded, usually two mini-screw implantpins should be implanted into the buccal side between maxillary firstmolar and second molar as well as the lingual side between the maxillaryfirst molar and second molar. In addition, maxillary first molar and secondmolar were intruded, two mini-screw implant pins should be respectivelyimplanted into the buccal sides between maxillary first molar and secondmolar, connecting the first molar and second molar with square wire. Theelastic chain strength on the square steel wire could intrude two themevenly. Buccal side implants should be located in the attached membranegingiva gum joint; lingual implants should be about 6mm from gingivalpapilla. Besides, they should keep away from the palatine major bloodvessels and nerves there. Local infiltration anesthesia was executed withPrimacaine. Mini-screw implant as anchorage was implanted withdedicated handle. Next, through X-ray, implant direction was observedand it was ensure that the planted anchorage didn’t hurt tooth root.1.3.2 Mini-screw implant stress applicationUsually, after mini-screw implants were implanted for two weeks,the stress is applied. When the maxillary first molar was intruded, elasticchain was used to connect the maxillary first molar buccal lingual implantanchorage, with the elastic chain crossing the maxillary first molar at adiagonal line. When the maxillary second molar was intruded, elasticchain was bonded to the square steel wire in the maxillary first and secondmolars, connecting with buccal and lingual implant pins. The loadingforce value for each mini-screw implant was about 75~200g. Patientswere instructed to check it once every three weeks, and keep miniscrewimplant surrounding clean so as to prevent the mini-screw implantloosening.1.4 Measuring methodBy taking the palatal plane (PP) of lateral cephalometricradiolographs as the reference [2], the vertical distance between mesialmolar and PP was measured and extruded molar intrusion was calculated.1.5 Statistical treatmentStatistical analysis was conduced through SPSS17.0 software. Thedata were denoted with to mean ± standard deviation. Paired t test wasapplied for the comparison before and after treatment. P ﹤ 0.05 showingthe difference was statistically significant.2. Results10 patients successfully completed treatment; the intruded toothroot didn’t appear obvious absorption and the missing teeth wererepaired. The vertical distance between mesial molar and PP of the 10patients was 32.06 ± 1.88mm before treatment and 29.10 ± 1.13 mmafter treatment, with the mean of 2.90 ± 0.75mm. The changes beforeand after treatment was statistically significant (t = 2.231, p < 0.05). Theaverage treatment time was （7.50±0.45） months.3. ConclusionsMini-screw implant pin, as a new and effective anchorage canrealize the intrusion of extruded molar. Ma Huaxiang and others [3]confirm that the method of mini-screw implant anchorage can intrudemolar for 2.40~4.50mm on average. In orthodontic clinical treatmentof extruded molar intrusion, mini-screw implant anchorage is moreconvenient, efficient, and comfortable more traditional fixed or mobileappliance.The safe implant of implant anchorage is the key to effectivelyintrude molars. Each patient was required to take lateral cephalometricradiolographs as well as the periapical radiography of extruded molars soas to analyze the root spacing and bone mineral density, prevent hurtingtooth root in the implant process and reduce the risks of postoperativeinplant pin loosening. At the same time, the patients were required toensure that the mini-screw implant surrounding clean after the operation.Li Chenxi [4] points out that the failure ratio of implant anchorage is 3.873when PLI increases each level.As for the force application timing of mini-screw implants: XuYan and others [5] think immediate loading of mini-screw implant isfeasible under the premise of strict control of trauma and force size. KangJing [6] and others point out that it has good loading stability after miniscrewimplants for two weeks while immediate loading has poor loadingstability. Besides, Zhang Bin etc. [7] propose the non-immediate stressapplication has more bone union and provide more stable anchorage thanimmediate stress application of mini-screw implant. Currently, in theclinical application, force application is added after 2~4 weeks for manymini-screw implants.About the choice of the required extruded molar intrusion, NiZhenyu [8] and others use the force of 50~200g to intrude three maxillaryteeth roots and there is no clear tooth root absorption. In the study, theforce value of 150~200g was used. In order words, each implant pin bearsthe force of about 75~100g; chain rubber band strength can effectivelyintrude extruded molar. According to some researches, the functiontime of correctional force is one of the important causes of tooth rootabsorption. The average treatment time of the present study is 7.50-0.45months and is shorter than conventional orthodontic treatment.The study result confirms that the mini-screw implant andreasonable treatment force can effectively intrude extruded molar for thespecific situation of patients with extruded molar intrusion. Mini-screwimplant anchorage is of strong clinical maneuverability and has no seriouscomplications, so it is worthy of clinical reference and promotion.References[1] Li Jun. Clinical Effect Comparison of Mini-Screw Implant asAnchorage and Traditional Orthodontic Treatment [J]. China ModernDoctors, 2013, 35:127-129.[2] Hong Shuo. Clinical Effect Research of Mini-Screw Implant asAnchorage for Extruded Molars Intrusion [J]. Chinese Journal of PracticalStomatology[J], 2013, 09: 547-549.[3] Ma Huaxiang, Guo Jing, Wu Zhong and Liu Yin. ClinicalResearch on Mini-Screw Implant as Anchorage for Extruded MolarsIntrusion [J]. Journal of Clinical Stomatology, 2013, 09: 537-539.[4] Li Chenxi. Clinical Research on the Effect of Related RiskFactors of Mini-Screw Implant Stability [D]. Hebei Medical University,2011.[5] Xu Yan, Zen Ke, Jing Xiwen, Wang Lin and Wang Zhendong.Stability Of Immediate Loading Orthodontic Mini-screw ImplantsAnchorage [J]. Stomatology, 2008, 12:623-625.[6] Kang Jing, Zhou Hong and An XiaoLi. Biology Research onthe Influence of Different Loading Time on Mini-screw Implant Stability[J]. Journal of Practical Stomatology, 2008, 02:205-208.[7] Zhang Bin, Zhang Jingfang, Wang Yang, Jia Wei, ZhaoYanping and Liang Yongqiang. Impact of Application of Force Time ofDiabetic Rats Mini-screw Implant on the Stability [J]. Chinese Journal ofCoal Industry Medicine, 2013, 11:1866-1868.[8] Ni Zhenyu, Lin Xinping, Hu Rongdang, Zheng Minling.Application of Mini-screw Implant as Anchorage for Molar Intrusion [J].Journal of Oral Science Research, 2005, 04:435-437.
论文作者:王涛 陈杰 梁珊珊
论文发表刊物:《中国医学人文》2016年第4期
论文发表时间:2016/6/30
标签：青岛大学论文; 期刊论文; 标号论文; 青岛论文; 尽在论文; 山东论文; 文章分类论文; 《中国医学人文》2016年第4期论文;