青年夜磨牙症患者经弹性牙合垫治疗前后咬合变化特征的研究

目的：：测量并分析夜磨牙症患者使用弹性垫治疗前后各项咬合数据变化。方法：使用弹性垫对青年夜磨牙症患者(n=10)进行治疗,并在治疗前和治疗后6个月使用T-Scan咬合检测仪进行咬合检测,观察和记录实验组闭合时间、分离时间、力中心位置、力不对称指数的变化,与对照组( n=10)进行对比和研究,并观察临床疗效。结果：治疗前实验组闭合时间及左、右侧分离时间均比对照组长(P<0.05),治疗后均无统计学差异(P>0.05);治疗前、后2组前伸分离时间差别无统计学意义(P>0.05);治疗前实验组和对照组力中心位置左右向偏移和右侧力百分比及力不对称指数比较均有统计学差异(P<0.05),治疗后比较均无统计学差异(P>0.05)。实验组治疗后闭合时间及左、右侧分离时间均比治疗前缩短(P<0.05);实验组治疗前、后右侧力百分比值有统计学差异(P<0.05),前伸分离时间、力中心位置偏移、左侧力百分比及力不对称指数治疗前后比较均无统计学差异(P>0.05)。结论：早接触、侧方干扰、全牙列力中心的偏移等咬合因素与磨牙症有十分密切的关系。使用弹性垫治疗磨牙症,可以有效地改善上述问题,使关系更加协调和稳定。     

青少年错畸形正畸治疗后前伸及侧方接触特征初探

目的研究青少年错畸形患者正畸后前伸及侧方接触特征。方法选择16例经正畸治疗获得正常牙列形态的青少年错畸形患者作为病例组,17名性别、年龄与病例组匹配的正常健康人作为对照组,使用T-ScanⅡ咬合分析系统记录2组受试者前伸及侧方运动,并比较2组的分离时间。结果病例组前伸及侧方干扰发生率较高, 干扰点多位于第二恒磨牙。病例组左侧方分离时间、右侧方分离时间及前伸分离时间分别为（1.504±0.681）、（1.532±0.913）、（1.358±0.791）s,对照组左侧方分离时间、右侧方分离时间及前伸分离时间分别为（0.470±0.059）、（0.483±0.045）、（0.482±0.047）s。病例组左侧方分离时间、右侧方分离时间及前伸分离时间均比对照组显著延长（P＜0.01）。结论与正常健康人相比,青少年错畸形患者正畸后前伸及侧方运动分离时间显著延长。     

青少年错患者正畸治疗后牙尖交错位接触特征变化初探

目的探讨经正畸治疗获得正常牙列形态的青少年错患者主动矫治结束后12个月内牙尖交错位接触的变化规律。方法选择20例正畸主动矫治结束后戴用标准霍利保持器的青少年错患者,使用T-ScanⅡ咬合分析系统分别于矫治结束即刻（T1）和矫治结束12个月时（T2）记录其牙尖交错位接触并进行比较。结果 20例患者T1至T2前牙接触面积及前牙力占总力的百分比有所减小,后牙接触面积及后牙力占总力百分比有所增加,但所有测量项目两时间点的差异均无统计学意义（P〉0.05）。结论戴用标准霍利保持器12个月后,患者牙尖交错位接触状况仅有轻微改善,主动矫治结束前的咬合检查及精细调整是必不可少的。     

正常(牙合)者咬合功能的研究

目的研究正常[牙合]者的咬合功能状况。方法用T-scan Ⅱ型系统4．02版记录26名正常[牙合]青少年在牙尖交错位（ICP）的[牙合]力总值（TOF）、[牙合]力不对称指数（AOF）、[牙合]力中心点位置（COF）、[牙合]力中心点最大位移（MMCOF）、[牙合]干扰指数（0II）、[牙合]接触点数（NOC）、[牙合]接触面积不对称指数（AOA）。分析[牙合]力及咬合接触点的分布规律。结果①正常[牙合]者三次咬合记录的左右侧[牙合]力百分比及COF无显著性差异。②正常[牙合]者AOF、MMCOF、OⅡ均较小，男性[牙合]力总值大于女性（P〈0．05）。③正常[牙合]者NOC主要分布在磨牙区，前牙几乎无接触，咬合接触点与[牙合]力成正相关。结论①T-scan Ⅱ系统传感器薄膜具有良好的重复性。②正常[牙合]者具有平衡稳定的咬合。     

青少年错(牙合)患者正畸治疗后动态(牙合)接触特征变化初探

目的 探讨经正畸治疗后获得正常牙列形态的青少年错(牙合)患者矫治结束后12个月内动态(牙合)接触的变化规律,以期为正畸矫治结束前的精细调整提供参考.方法 选择20例正畸矫治后戴用标准霍利保持器的青少年患者,并将20例患者分为(牙合)干扰组与无(牙合)干扰组,其中(牙合)干扰组患者11例,无(牙合)干扰组9例,使用T-ScanⅡ咬合分析系统分别于矫治结束即刻(T1)和矫治结束12个月(T2)时检查患者的动态(牙合)接触,对比分析两个时间点总体与分组情况下患者动态(牙合)接触特征.结果 20例患者的总体情况:T1至T2的前伸、左侧方和右侧方(牙合)分离时间明显减少,从(1.07±0.87)、(0.91±0.47)、(0.76±0.43)s分别降至(0.43±0.25)、(0.67±0.41)、(0.50±0.27)s,两时间点差异均有统计学意义(P＜0.05).其中4例存在(牙合)干扰的患者(牙合)干扰消失.1例出现(牙合)干扰侧咀嚼肌不适症状.无(牙合)干扰组T1至T2的前伸、左侧方和右侧方(牙合)分离时间明显减少,从(1.25±1.11)、(0.84±0.15)、(0.52±0.49)s降至(0.35±0.15)、(0.36±0.15)、(0.33±0.11)s,两时间点差异均有统计学意义(P＜0.05),(牙合)干扰组T1与T2的前伸、左侧方和右侧方(牙合)分离时间的差异无统计学意义(P＞0.05).结论 戴用标准霍利保持器12个月后患者的动态(牙合)接触总体改善,但(牙合)干扰的存在影响了咬合的自行改善进程,矫治器拆除前对动态抬(牙合)接触的评估与精细调整仍是必要的.     

安氏Ⅱ类1分类错（牙合）患者正畸前后咬合功能的研究

目的 研究安氏Ⅱ类1分类错（牙合）患者矫治前中后的咬合功能变化,分析评价固定矫治技术对牙颌功能的影响.方法 选择26名安氏Ⅱ类1分类错（牙合）患者,运用T-scan Ⅱ型咬合测量分析系统,记录其在矫治前、中、后牙尖交错位的（牙合）力（TOF）、（牙合）力不对称指数（AOF）、（牙合）接触点数（NOC）、（牙合）接触面积不对称指数（AOA）、（牙合）力中心点位置（COF）、（牙合）力中心点最大位移（MMCOF）及（牙合）干扰指数（OII）七项指标.结果 与矫治前相比,矫治中TOF及NOC下降,而矫治后升高（P＜0.05）,矫治后AOF、AOA、COF、MMCOF及OII均明显下降（P＜0.01）.结论 安氏Ⅱ类1分类错（牙合）患者正畸治疗后,咬合功能增强,明显消除了（牙合）不对称等不利因素,咬合功能更加平衡协调.     

减数正畸治疗的咬合接触特征分析

目的:了解不同人群ICP咬合接触特征的差异以及正畸治疗对咬合的影响。方法:选取20名个别正常牙合者(A组)、20名错牙合畸形者(B组)、30名正畸治疗结束者(C组),通过Tee-test咬合分析系统对全牙列总接触面积(Total contact area,TCA)、全牙列咬合总力值(Total occlusion Force, TOF)、单位面积力值、咬合力中心点位置(Centre of Force, COF)、牙合不对称指数(Asymmetry index of occlusal force, AOF)、全牙列牙合力分布等数据进行分析比较。结果:A组TCA、TOF显著大于B、C组(P<0.05);C组的单位面积力值略小于A组,COF、AOF略大于A组,其组间差异无统计学意义,B组与A、C组间差异有统计学意义(P<0.05);A、B组的最大咬合力分布在第二磨牙区,C组的最大咬合力分布在第一磨牙区(P<0.05);不同性别间3组咬合测量项目差异均无统计学意义。结论:通过正畸治疗,咬合接触明显改善,咬合均衡性好,但未达到个别正常牙合的理想状态,提示正畸治疗后期的精细调整很重要。     

无牙颌种植固定修复的咬合分析

目的 探讨全口无牙颌患者应用固定种植修复后的咬合特点。方法 选取30例全口无牙颌种植固定修复患者作为试验组,30例天然牙列受试者作为对照组,使用Teetester数字化咬合分析系统分析二者在牙尖交错位、前伸颌位、侧方颌位等不同位的咬合时间及咬合力分布等特点。结果 牙尖交错位时,试验组的咬合接触时间、最大咬合力均小于对照组（P<0.05）,而最大咬合力时左右侧咬合力平衡度则相反;前伸颌位时,试验组的咬合分离时间小于对照组（P<0.05）;侧方颌位时,试验组的咬合接触时间小于对照组（P<0.05）。二者的平均咬合压力、前牙区总受力百分比、侧方颌的颌型均无统计学差异。结论 全口无牙颌种植固定修复患者牙尖交错位时的最大咬合力会降低,但与天然牙列相似的是,前伸颌位时咬合力量均集中在前牙区,侧方颌位时均以组牙功能为主。     

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目的研究安氏Ⅱ1错矫治前后咬合功能状况的变化,借以评价正畸治疗对咬合接触变化的影响,并结合国内外学者的相关研究数据,对比分析本研究对安氏Ⅱ1错咬合稳定重建的可靠程度及对临床的指导意义。方法选取2008-2012年来济南市口腔医院正畸科就诊的安氏Ⅱ1错患者30例,用T-scanⅡ数字化咬合分析系统记录患者矫治前后最大牙尖交错位的力总值(TOF)、力不对称指数(AOF)、力中心点位置(COF)、力中心点的最大位移(MMCOF)、闭合时间(TO),并进行统计分析。结果安氏Ⅱ1错患者矫治后TOF高于矫治前(P<0.01);矫治后COF距上颌中线的距离与矫治前相比减小(P<0.01);矫治后AOF、MMCOF、TO均低于矫治前(P<0.01)。结论正畸治疗能够改善安氏Ⅱ1错患者的力水平及平衡性;T-scanⅡ数字化咬合分析系统能够客观、真实、准确的显示咬合接触状态,其测量结果可作为临床评价的指标。     

T-ScanⅡ咬合分析数据作为早期牙隐裂调(牙合)干预指标的应用研究

目的:探讨牙隐裂(cracked tooth syndrome,CTS)患者动态咬合特征,分析其异常(牙合)因素,探索T-Scan Ⅱ咬合力分析系统作为牙隐裂调(牙合)干预指标之一的可行性.方法:T-ScanⅡ咬合力分析系统记录15名早期牙隐裂患者调胎干预前后牙尖交错位(ICP)及左右侧方咬合的过程.定量测定(牙合)接触点数目、力的中心点(COF)相对位置、(牙合)力百分比值(%)以及不对称系数等,并进行统计分析.结果:CTS组干预前第一磨牙区咬合接触点数目及(牙合)干扰次数明显多于对照组(P＜0.01)及干预后(P＜0.05).CTS组COF均偏于患侧,两组患侧(牙合)力百分比值有统计学差异(P＜0.05).结论:局部较大胎力和不均衡的咬合接触是牙隐裂患者主要(牙合)紊乱因素.T-ScanⅡ咬合力分析数据可作为牙隐裂早期干预性调(牙合)的指标之一.     

青少年错(牙合)畸形正畸后牙尖交错位(牙合)接触特征初探

目的 通过了解青少年错(牙合)畸形正畸后牙尖交错位的(牙合)接触特征,从功能角度对正畸效果进行评价.方法 选择14例经正畸治疗获得正常牙列形态的青少年错(牙合)畸形患者作为病例组,17名性别、年龄与病例组匹配的正常(牙合)健康人作为健康对照组,使用T-ScanⅡ咬合分析系统记录两组牙尖交错位的(牙合)接触特征并进行比较.结果 在1/10、1/4、1/2、3/4最大(牙合)力页面及最大(牙合)力页面上病例组前牙(牙合)接触点数目的 中位数(四分位数间距)分别为1.5(1.0)、3.0(1.3)、4.5(3.3)、5.5(3.0)及5.5(3.3)个,显著大于健康对照组[分别为0.0(0.3)、0.0(0.6)、0.3(0.5)、0.3(1.0)及0.0(1.8)个,P＜0.05];各页面上病例组后牙(牙合)接触面积与健康对照组的差异无统计学意义(P＞0.05);与健康对照组相比,病例组(牙合)力中心点明显偏近中.病例组牙尖交错位建(牙合)时间的中位数(四分位数间距)为0.192(0.141)s,略大于健康对照组[0.163(0.200)s],但两组差异无统计学意义(P＞0.05).结论 与正常猞健康人相比,青少年错(牙合)畸形患者正畸后其前牙承受(牙合)力明显偏大.     

Influence of clenching intensity on bite force balance, occlusal contact area, and average bite pressure.

It has been difficult for investigators to simultaneously and reliably evaluate bite force in the intercuspal position with the area and location of occlusal contacts. This study was designed to investigate the variations in these parameters with respect to two factors: three levels of clenching and the preferred chewing side. Human subjects with normal occlusion were examined with a recently developed system (Dental Prescale Occluzer, Fuji Film, Tokyo, Japan). The three levels of clenching intensity were assessed by masseteric EMG activity and included the maximum voluntary contraction, and 30% and 60% of the maximum. The results indicated that the bite force and occlusal contact area on the whole dental arch increased with clenching intensity. In contrast, the average bite pressure, obtained by dividing the bite force by the contact area, remained unchanged regardless of the clenching intensity. As the clenching intensity increased, the medio-lateral position of the bite force balancing point shifted significantly (P<0.01) from the preferred chewing side toward the midline. The antero-posterior position remained stable in a range between the distal third of the first molar and the mesial third of the second molar. The bite force and occlusal contact area, which were mainly on the molars, increased with the clenching intensity, whereas the proportions of these two variables on each upper tooth usually did not change significantly. The exception was the second molar on the non-preferred chewing side. When comparisons were made between pairs of specific upper teeth of same name, usually no significant difference was found in bite force or occlusal contact area, regardless of the clenching level. Again, the exception to this observation was the second molar on the preferred chewing side, which had a larger area at the 30% clenching level. The results in normal subjects suggest that as the clenching intensity increases in the intercuspal position, the bite force adjusts to a position where it is well-balanced. This adjustment may prevent damage and overload to the teeth and temporomandibular joints.     

An adult case of skeletal open bite with a large lower anterior facial height

Control of the height of posterior dentoalveolar regions is of great importance for the correction of skeletal open bite. Traditionally, second premolar extraction facilitates the closure of open bite by inducing a counterclockwise mandibular rotation without molar intrusion. This article reports treatment for a 24-year six-month-old female patient with an open bite and large anterior facial height. She complained of occlusal disturbances and difficulty of lip closure because of the open bite. Overjet and overbite were +3.0 mm and -3.0 mm, respectively. To correct open bite and crowding, the bilateral extraction of the maxillary and mandibular second premolars plus multibracket appliances for mesial movement of the molars was selected as the treatment plan. After a two-year treatment, an acceptable occlusion was achieved, the lower anterior facial height was decreased, and the lips showed less tension in a lip closure. An acceptable occlusion was maintained without recurrence of the open bite during a three-year retention period, indicating a long-term stability of the occlusion. The results of this treatment indicated that the correction of open bite with no or less molar intrusion or incisor extrusion is of great importance for achieving stable occlusion and avoiding the relapse of open bite.     

Bilateral Open Bite in Dicygotic Twins. A Combined Orthodontic-Prosthetic Approach

CASE REPORT: Dizygotic twins, male, 25 years of age, required treatment for an identical orthodontic diagnosis. DIAGNOSIS: Class III malocclusion with mesial molar relation and frontal edge-to-edge bite, lyrate upper dental arch, grouped cross-bite and bilateral open bite in the molar and bicuspid region, retention and lingual inclination respectively of the lower left second bicuspid, mesial inclination of both lower first molars. The severity of the malocclusion differed in the two brothers. THERAPY: Orthodontic treatment was successful concerning the transversal expansion and alignment of the maxillary dental arch, the functional relation of the anterior teeth, the transversally correct relation of the upper and lower dental arches and, following surgical removal of the lower second bicuspids, the reduction of crowding in the lower arch. An attempt was made to upright the molars in the mandibular arch and to close the lateral open bite by means of vertical elastics. However, the 10-month period of resistance to the therapy suggested, after a tongue protrusion habit had been ruled out, a diagnosis of ankylosis. Further orthodontic treatment was renounced and a prosthetic solution was pursued instead: the teeth in infraocclusion were treated with full ceramic overlays and, in the regions with residual gaps, with pontics (Empress II, Ivoclar, Schaan, Liechtenstein), after minimally invasive preparation (confined to removal of existing fillings). CONCLUSION: This case is particularly interesting because the infrapositioned molars in both brothers were very likely due to ankylosis, suggesting a genetic cause.     

Osteotomy assisted maxillary posterior impaction with miniplate anchorage

This case report presents orthodontic treatment with miniplate anchorage accelerated by osteotomy-assisted maxillary posterior impaction in a severe open bite case. A 14-year-old girl with a severe anterior open bite was treated by intrusion of the maxillary posterior teeth. A segmental osteotomy was applied, and the miniplates were fixed to the zygomatic buttress area. The intrusive force was applied with nickel-titanium closed coil springs using a force of 250 g between the miniplates and the upper first and second molar buccal tubes. The intrusion was completed 2.5 months after osteotomy. The treatment was continued with the fixed orthodontic appliances and completed after 12 months. At the end of treatment, optimal occlusion and the correction of the anterior open bite were achieved. The maxillary molars were impacted 4.0 mm, and the mandibular plane showed a counterclockwise autorotation of 3.0 degrees . The results showed that osteotomy-facilitated orthodontic treatment clearly reduced the treatment time and had no adverse effects. In conclusion, this one-stage osteotomy technique can be an effective option to help molar intrusion in severe open bite cases.     

Bite force in children with unilateral crossbite before and after orthodontic treatment. A prospective longitudinal study

In this prospective, longitudinal study, bite force was examined in children with a unilateral posterior crossbite before (stage 1), immediately after orthodontic treatment (stage 2), and after retention (stage 3). The sample comprised 19 (7 girls, 12 boys) children aged 7-11 years. The children were treated according to conventional practice, with an expansion plate (seven subjects) or a quadhelix appliance (12 subjects). Unilateral bite force was measured at the first molars by means of a standardized method. Statistical analysis was undertaken using Shapiro-Wilks W- and t-tests, and analysis of variance. There was no significant difference in bite force regarding age, gender, appliance, or side, i.e. right or left molar region. However, during stage 2 the bite force was significantly lower ipsilaterally to the crossbite than contralaterally (P<0.05). In general, the bite force was systematically lower than reference values, but the mean bite force (P<0.05) and the bite force on the ipsilateral side (P<0.01) increased significantly from stage 2 to stage 3. The bite force level was reduced immediately after treatment, but increased again after retention and approached the bite force level in children with neutral occlusion. The fluctuation in bite force level during orthodontic treatment may be due to transient changes in occlusal support, periodontal mechanoreceptors, and jaw elevator muscle reflexes.     

正畸治疗中下颌第二磨牙近中倾斜萌出相关因素的研究

目的 探讨正畸治疗过程中影响下颌第二恒磨牙近中倾斜萌出的因素。方法 选取78例正畸治疗患者,初诊时4个第二磨牙均未萌出,正畸治疗结束时,4个第二磨牙萌出建,且第二磨牙未经治疗。用Logistic回归分析正畸治疗后下颌第二磨牙近中倾斜发生与第三磨牙的牙胚存在与否、是否拔牙、下颌平面角、错类型、下颌牙弓前中段拥挤度、牙弓后段拥挤度和第一磨牙前移量之间的关系。结果 下颌第二磨牙近中倾斜与治疗过程中第一磨牙的前移量密切相关(P<0.001),其它因素排除在外,逐步回归方程为Y=1.153×第一磨牙前移量-2.855。结论 正畸治疗过程中过多前移第一磨牙,易导致第二磨牙近中倾斜。