Assessment of respiratory muscle strength and airflow before and after microimplant-assisted rapid palatal expansion

Objectives:To assess alterations in respiratory muscle strength and inspiratory and expiratory peak flow, as well as skeletal and dental changes in patients diagnosed with transverse maxillary deficiency before and after microimplant-assisted rapid maxillary expansion (MARPE).Materials and Methods:Twenty patients (13 female and 7 male) were assessed by respiratory tests in three different periods: T0 initial, T1 immediately after expansion, and T2 after 5 months. Tests included: maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP), oral expiratory peak flow, and inspiratory nasal flow. Cone-beam computed tomography measurements were performed in the maxillary arch, nasal cavity, and airway before and immediately after expansion.Results:There was a significant increase in MIP between T0 and T2 and MEP between T0 and T1 (P<.05). Oral and nasal peak flow increased immediately after and 5 months later, especially in patients with initial signs of airway obstruction (P<.05). In addition, after expansion there was a significant enlargement of the nasal cavity, alveolar bone, and interdental widths at the premolar and molar region. Molars tipped buccally (P<.05) but no difference was found in premolar inclination. MARPE increased airway volume significantly.Conclusions:Skeletal changes promoted by MARPE directly affected airway volume, resulting in a significant improvement in muscle strength and nasal and oral peak flow.     

Jaw muscle silent periods by tooth tap and chin tap

Electromyographic silent periods from jaw closing muscles were elicited during a clench by tapping on the chin and on selected teeth both in asymptomatic subjects and in subjects reporting symptoms of temporomandibular joint dysfunction. The mean duration in response to a chin tap was significantly shorter in the asymptomatic group than in the dysfunction group. No significant differences in mean duration elicited by tooth taps were found between groups. Other comparisons of mean durations such as among muscles, among teeth, or between chin taps and tooth taps failed to achieve statistical significance.     

Transverse changes after surgically assisted rapid palatal expansion

The aim of this retrospective study was to investigate the amount of skeletal and dental expansion in patients submitted to surgically assisted rapid palatal expansion (SARPE). The sample consisted of 21 patients (14 female and seven male) with a mean age of 25.4 years (range 17.4–41.8 years). Postero-anterior (PA) cephalograms were taken pre-expansion (T1), immediately after expansion (T2), and at post-expansion retention of 120 days (T3). SARPE promoted significant transverse skeletal changes, which were maintained from T2 to T3. Dentoalveolar expansion and dental tipping were also observed in the region of the first molars and first premolars; however the net effect at the first molars was significantly less than that at the first premolars. No statistically significant effect on the width of the nasal cavity was observed. The findings indicate that peculiarities inherent to dental effects may influence the clinical options for SARPE. Skeletal expansions with SARPE were significant and stable. Dental changes were different between molars and premolars. The transverse changes after SARPE should be observed for future procedures related to the retention and the completion of orthodontic treatment.     

Nasomaxillary effects of miniscrew-assisted rapid palatal expansion and two surgically assisted rapid palatal expansion approaches

This retrospective study was performed to evaluate nasomaxillary changes in 36 patients at an advanced stage of skeletal maturity who underwent miniscrew-assisted rapid palatal expansion (MARPE) or surgically assisted rapid palatal expansion (SARPE) with/without an alar base cinch. Cone beam computed tomography images taken before and after expansion were analysed. Changes in the width of the dental arch (D66S, D66I), maxillary base (MxMol), and nasal floor and nasal cavity in the molar and canine regions (NaFMol, NaFCan, NaCMol, NaCCan) were compared, as well as changes in the choanal aperture (CA) and nasal soft tissue (NW). The MARPE technique produced smaller dental changes (D66S; P = 0.025) and greater nasomaxillary expansion (MxMol, P = 0.010; NaCMol, P = 0.016; NaCCan, P = 0.017; NaFMol, P = 0.001; CA, P = 0.002) than both SARPE techniques. Changes in NW did not differ significantly between the groups (P = 0.200). MARPE uniformly increased the anterior and posterior widths of the nasal cavity. SARPE expanded the nasal cavity in a ‘V-shape’ pattern. Changes in the nasal cavity and choanal aperture related to the amount of dental arch expansion were greater for MARPE than for SARPE. All three approaches increased the width of the nasal soft tissue, although the cinch in SARPE limited this increase.     

A comparison of dental and dentoalveolar changes between rapid palatal expansion and nickel-titanium palatal expansion appliances.

A tandem-loop nickel titanium temperature-activated palatal expansion appliance was developed that produces light, continuous pressure on the midpalatal suture and requires little patient cooperation or laboratory work. The purpose of this study was to compare the effectiveness of the nickel titanium palatal expansion appliance with that of a rapid palatal expansion appliance. The study sample comprised 25 patients who required palatal expansion as part of their orthodontic treatment. The sample was divided into 2 groups, with 13 patients in the nickel titanium group and 12 patients in the rapid palatal expansion group. Study models were taken before treatment and at the end of the retention period after expansion. Intermolar width, palatal width, palatal depth, alveolar tipping, molar tipping, and molar rotation were analyzed. In addition, occlusal radiographs were obtained before and 2 weeks after expansion to evaluate for sutural separation by the appliances. Results showed significant increases in midpalatal sutural separation, tipping of the alveolus, and tipping of the molars after expansion in both groups. However, greater midpalatal sutural separation was found in the rapid palatal expansion group and greater molar rotation was found in the nickel titanium group. Stepwise multiple regression analysis showed that alveolar tipping, palatal width change, and molar tipping are the best predictors of intermolar width change in the rapid palatal expansion group. Radiographic evidence of midpalatal sutural separation was less obvious in the nickel titanium group. These results suggest that both the nickel titanium and the rapid palatal expansion appliances are capable of expanding the maxillary dentition and alveolar process and are equally capable of correcting posterior crossbites. In the current study, the rapid palatal expander widened the palate more reliably, whereas the nickel titanium expander tipped the molars buccally to a greater extent and caused more distal molar rotation. The clinician's choice of expander will depend on his or her initial diagnosis and treatment goals.     

Dental tipping and rotation immediately after surgically assisted rapid palatal expansion

The purpose of this investigation was to evaluate the effects of dental tipping and rotation immediately after surgically assisted rapid palatal expansion (SARPE). Fourteen patients (10 females, four males; mean age 25.6 years) who required a SARPE procedure were available for this study. A palatal expander appliance was cemented on four abutment teeth (first premolars and first molars) of each patient 1 week prior to surgery. Maxillary study models were taken before surgery and 2-3 weeks after full expansion (7 mm). Each model was trimmed to have the base parallel to its occlusal plane. From an occlusal view, measurements were made to determine if the abutment teeth underwent rotation from SARPE. From a postero-anterior view, the abutment teeth were examined for any tipping effect due to SARPE. The results showed that from pre- to post-expansion, the two first premolars displayed 2.32 +/- 8.29 degrees of mesiobuccal rotation (P > 0.05) and the two first molars displayed 3.09 +/- 5.89 degrees of mesiobuccal rotation (P > 0.05). Each first premolar showed 6.48 +/- 2.29 degrees of buccal tipping (P < 0.05) and each first molar 7.04 +/- 4.58 degrees of buccal tipping (P < 0.05). SARPE induced a slight mesiobuccal rotation (P > 0.05) and significant buccal tipping of the first premolars and the first molars (P < 0.05). Some overexpansion is suggested to counteract the relapse effect of buccal tipping of the posterior teeth that takes place during SARPE.     

Spontaneous correction of Class II malocclusion after rapid palatal expansion

A case of a Class II, division 1 malocclusion with reduced transpalatal width is reported. The only treatment provided for this patient was rapid palatal expansion. After expansion, the mandible seemed to be carried forward to its normal position, resulting in a spontaneous correction of the Class II malocclusion. This case report illustrates the outcome of the method of treatment used with a long-term (14-year posttreatment) follow-up.     

快速上颌扩弓保持与复发的动物实验研究

目的 :研究腭中缝扩张 (Sd Sd)、牙槽突倾斜和弯曲 (At b At b)、牙齿移位 (Td Td)、牙齿倾斜 (Tt Tt)在快速扩弓、保持和复发结束时的比例变化及该变化与扩弓稳定性的关系。方法 :选择 6周龄SD雄性大鼠 2 4只 ,随机分为 3组 ,每组均设实验组 6只和对照组 2只 ,实验组经过快速扩弓期 ( 1周 )、保持期( 4周 )、复发期 ( 4周 ) ,对照组不作扩弓处理 ,制作四环素荧光标记不脱钙磨片 ,在荧光显微镜下观察并将图像输入计算机分析仪测量腭中缝的宽度 (SW )、磨牙颊尖区增宽的量 (即扩弓量M M )和磨牙牙槽嵴增宽的量 (RM RM) ,从而利用公式计算出 4个部分的比例。结果 :磨牙扩弓量 (M M )在扩弓结束时、保持结束时、复发结束时 4部分 [(Sd Sd) :(Tt Tt) :(At b At b) :(Td Td) ]的比例变化为 :45 .2 % ( 0 .47mm ):17.8% ( 0 .19mm) :2 5 .7% ( 0 .2 7mm) :11.4% ( 0 .12mm ) -5 2 .3 % ( 0 .47mm) :15 .5 % ( 0 .14mm ):18.9% ( 0 .17mm) :13 .3 % ( 0 .12mm) -61.8% ( 0 .3 4mm) :18.2 % ( 0 .10mm) :1.8% ( 0 .0 1mm) :18.2 % ( 0 .10mm )。结论 :腭中缝扩张 (Sd Sd)是快速上颌扩弓中最重要的部分 ,其稳定性关系到扩弓的成败。     

Maxillary incisor root resorption after rapid palatal expansion in Felis catus

Root resorption after rapid palatal expansion (RPE) treatment was found in anchored teeth but has not been studied on non-anchored incisors. This study evaluated root resorption, root tipping, and root proximity of maxillary incisors after RPE treatment. Fourteen cats were divided into treated (n = 10) and untreated (n = 4) groups. The RPE treatment consisted of active, retention, and relapse phases, lasting 25, 60 and 60 d, respectively. Standardized occlusal radiographs were taken to measure tipping and root proximity before and after each treatment phase. Maxillary incisors were analysed histologically by fluorescent microscopy for root resorption. Data was analysed statistically with anova with repeated measures, t-test and Pearson's coefficient of correlation. Root resorption was confined to the first incisors and was 750-fold greater in the treated vs. the control group. Root tipping and root proximity were significantly greater (2.5- and 17-fold, respectively) in the first than in the second maxillary incisor and highly correlated with root resorption (r = -0.927 and 0.723, respectively). This suggests a cause (tipping and root proximity) and effect (root resorption) relationship. Data suggest that first maxillary incisor susceptibility to root resorption during RPE is associated with severe tipping and root proximity.     

加力时间对快速扩弓效果的影响初探

目的 采用不同加力时间进行正畸快速扩弓治疗,探讨不同加力时间对快速扩弓治疗的影响和作用,为正畸临床治疗提供依据.方法 纳入111例行快速扩弓治疗的连续病例,根据性别分组,男性组55例,女性组56例;平均年龄:男性(11.2±2.1)岁、女性(11.4±2.7)岁,均采用相同固定快速扩弓装置.每组分为0、3、6、9、12、15、18、21点8个时间点亚组加力,每组加力方式相同,每日加力9.8 N.通过模型分析测量扩弓量,并进行余弦拟合及方差分析.结果 每组8个时间点亚组正畸扩弓量符合余弦函数拟合昼夜节律规律.快速扩弓治疗的扩弓量峰值出现在21点,男性第一磨牙区扩弓量为(6.85±0.10)mm,女性为(6.81±0.15)mm;男性尖牙区扩弓量为(5.75±0.12)mm,女性为(5.54±0.14)mm.而扩弓量谷值出现在9点,男性第一磨牙区扩弓量为(5.88±0.15)mm,女性为(5.76±0.10)mm;男性尖牙区扩弓量为(4.26±0.19)mm,女性为(4.17±0.10)mm.每组8个时间点亚组扩弓量差异均有统计学意义(P＜0.05).结论 不同加力时间可以影响正畸扩弓治疗的效果.快速扩弓治疗较适合在21点前后加力.     

Arch perimeter changes on rapid palatal expansion

Relationships between changes in arch perimeter and arch width resulting from rapid palatal expansion with the Hyrax appliance were analyzed with the use of dental study casts of 21 adolescent patients. Photographs and measurements from the dental casts obtained before treatment and approximately 3 months after stabilization were used. Regression analysis indicated that changes in premolar width were highly predictive of changes in arch perimeter (r2 = 0.69) at approximately 0.7 times the premolar expansion. Without any orthodontic appliances attached to the mandibular teeth in 16 of the 21 patients, buccal uprighting of the posterior teeth was observed because of the redirection of occlusal forces. In addition, posterior movement of the maxillary incisors and buccal tipping of the anchor teeth were quantified. The prediction of arch perimeter change for a given amount of expansion is helpful in the treatment planning of rapid palatal expansion cases and may facilitate nonextraction orthodontic treatment.     

手术辅助腭扩展技术的应用进展

手术辅助腭扩展技术是通过外科手术方法进行上颌骨颊侧及腭中缝骨皮质切开,术后采用固定扩弓矫治器扩弓。本文对由于各种原因特别是唇腭裂引起的上颌骨横向发育不足的病例进行手术辅助腭扩展的适应证、手术方式、术后并发症及其对颅颌面的影响进行了综述。     

Changes in pharyngeal aerobic microflora in oral breathers after palatal rapid expansion

Background  

The purpose of this study was to investigate in oral breathing children the qualitative and quantitative effects on aerobic and facultatively anaerobic oropharyngeal microflora of respiratory function improved by rapid palatal expansion (RPE).     

快速上颌扩弓后局部应用二磷酸盐对腭中缝复发率的影响

目的 :探讨快速上颌扩弓后二磷酸盐 (BP)对大鼠腭中缝复发率的影响。方法 :6周龄SD雄性大鼠 88只 ,随机分为 11组 ,进行快速上颌扩弓实验 :快速扩弓 1周、保持 2周或 4周、复发后 4周。在保持期大鼠根据保持时间和注射BP的剂量不同分为 5种不同的处理方式 ,分别在扩弓结束、保持结束、复发结束时处死大鼠 ,制作脱钙及不脱钙切片 ,比较 5种处理方法大鼠扩弓后的复发率 (RR)、矿化沉积速率 (MAR )、破骨细胞的数量 (ON )。结果 :保持期注射BP的剂量不同明显影响扩弓后的复发率。结论 :快速上颌扩弓后局部应用二磷酸盐能减少大鼠腭中缝区破骨细胞的数量 ,加快新骨的矿化沉积速率 ,形成更多的新骨以减少扩弓后的复发率