“M"状曲推磨牙远移的临床效果

目的：研究“M”状曲推磨牙向远中的临床应用效果。方法：选择11例恒牙早期上颌轻度前突或拥挤、下颌正常或轻度后缩的安氏Ⅱ类患者,应用“M”状曲推磨牙向远中同时配合Ⅱ类颌间牵引,并通过远移前后的X线头影测量观察其上下颌磨牙移动的变化。结果：应用“M”状曲推磨牙向远中2～4个月后,安氏Ⅱ咬合关系恢复至安氏Ⅰ类关系。上颌第一磨牙向远中平均移动2．6mm,下颌第一磨牙向近中平均移动1．8mm。结论：只要病例选择合适,方法运用得当,“M”状曲能获得较满意的远移磨牙的疗效。     

Distribution,prevalence, and impact on the metatarsosesamoid complex of first metatarsal pronation in hallux valgus

BackgroundPrevious simulated weight-bearing CT (WBCT) studies classifying first metatarsal (M1) pronation suggested a high prevalence of M1 hyper-pronation in hallux valgus (HV). These findings have prompted a marked increase in M1 supination in HV surgical correction. No subsequent study confirms these M1 pronation values, and two recent WBCT investigations suggest lower normative M1 pronation values. The objectives of our WBCT study were to (1) determine M1 pronation distribution in HV, (2) define the hyperpronation prevalence compared to preexisting normative values, and (3) assess the relationship of M1 pronation to the metatarso-sesamoid complex. We hypothesized that the M1 head pronation distribution would be high in HV.MethodsWe retrospectively identified 88 consecutive feet with HV in our WBCT dataset and measured M1 pronation with the Metatarsal Pronation (MPA) and α angles. Similarly, using two previously published methods defining the pathologic pronation threshold, we assessed our cohort’s M1 hyper-pronation prevalence, specifically (1) the upper value of the 95% confidence interval (CI95) and (2) adding two standard deviations at the mean normative value (2 SD). Sesamoid station (grading) was assessed on the coronal plane.ResultsThe mean MPA was 11.4+/−7.4 degrees and the α angle was 16.2+/−7.4 degrees. According to the CI95 method, 69/88 HV (78.4%) were hyperpronated using the MPA, and 81/88 HV (92%) using the α angle. According to the 2 SD method, 17/88 HV (19.3%) were hyperpronated using the MPA, and 20/88 HV (22.7%) using the α angle. There was a significant difference in MPA among sesamoid gradings (p = 0.025), with a paradoxical decrease in MPA when metatarsosesamoid subluxation was increased.ConclusionM1 head pronation distribution in HV was higher than in normative values, but threshold change demonstrated contradictory hyper-pronation prevalences (85% to 20%), calling into question the previously reported high prevalence of M1 hyper-pronation in HV. An increase in sesamoid subluxation was associated with a paradoxical decrease in M1 head pronation in our study. We suggest that a greater understanding of the impact of HV M1 pronation is warranted before routine M1 surgical supination is recommended for patients with HV.Level of evidenceLevel III, retrospective cohort study.     

牙本质基质颗粒大小及脱矿条件对其性能的影响

目的 观察牙本质基质制备粒度与脱矿程度对其性能的影响。方法 选取成年家兔的上颌门牙随机分为2组，A组：采用稀盐酸（HCL）溶液（浓度1 mol/L）脱矿45 min，干燥后制备成3种不同粒径（400μm以下、400-800μm、800-1200μm）的脱矿牙本质基质材料（Demineralized dentin matrix，DDM），进行扫描电镜及静态接触角检测；B组：采用3种不同浓度（1 mol/L、0.5 mol/L和0.25 mol/L）的HCL溶液脱矿45 min，干燥后制备成粒径400μm以下的牙本质基质材料，分别进行红外光谱检测及电子能谱仪钙元素测定。结果 扫描电镜显示粒径400μm以下的DDM材料呈片状，随机观察牙本质小管充分暴露。A组3种DDM材料的静态接触角由粒径从小到大分别为6.0°、67.0°和96.7°。B组红外光谱检测显示：随着HCL溶液浓度增大，DDM材料中以羟基磷灰石为代表的无机物含量随之降低（P<0.05），但胶原的含量受影响较小；钙元素测定显示：在一定范围内随着脱矿程度增加，样品钙含量呈现梯度式降低（P<0.05）。结论 粒径较小的DDM材料牙本质小管暴露更充分，且具有更优的亲水性，脱矿程度的增加会降低DDM材料中无机物的含量，但对胶原含量影响较小。     

Evaluation of facial soft tissue asymmetric changes in Class III patients after orthognathic surgery using three-dimensional stereophotogrammetry

The aim of this study was to investigate changes in facial soft tissue asymmetry over time after orthognathic surgery in Class III patients using three-dimensional stereophotogrammetry. The study included 101 patients with a skeletal Class III malocclusion (72 female, 29 male; age range 19–53 years, mean age 28.6 years) who underwent orthognathic surgery. The minimum follow-up was 12 months. Three-dimensional photographs were acquired using the 3dMDtrio stereophotogrammetry system, and 21 anthropometric landmark positions were evaluated at three time points: before surgery (T0), 6 months (T1) and 12 months (T2) after surgery. Facial asymmetry was assessed and classified as follows: 0–2 mm, mild; 2–5 mm, moderate;> 5 mm, severe. The average distance for whole face asymmetry differed between T0 (median 0.76 mm) and T1 (median 0.70 mm); however, there was no statistically significant difference at any time point. The chin volume asymmetry score differed significantly between T0 (median 1.11 mm) and T1 and T2 (median 1.08 mm for both; P < 0.001 and P = 0.001, respectively), but not between T1 and T2 (P = 0.061). The study findings indicate that the asymmetry of the facial soft tissues has the potential to return after 6 months, without reaching the baseline.     

The long-term effect of maxillary advancement and impaction on subjective and objective nasal patency: A retrospective case-control study

The aim of this study was to investigate the change of nasal patency after maxillary advancement and impaction (MAX_ADV + IMP) in subjects with skeletal class III malocclusion (cases) and after removal of maxillary cysts in close proximity to the nasal floor in subjects that served as controls. NOSE score, volume derived by computed tomography (VOL), and acoustic rhinometry and rhinomanometry were retrospectively evaluated, before and one year after surgery. The movement of specific landmarks was also measured. NOSE score did not change after surgery, neither in 17 cases (p = 0.10) nor in 17 controls (p = 0.14). In cases, VOL_postop (10088 ± 4200 mm³) was significantly higher than VOL_preop (7807 ± 3721 mm³; p = 0.036). Maxillary advancement and inferior displacement of the ventral maxilla were noted by the movement of incisive foramen in the coronal (3.9 ± 5.4; p = 0.011) and Frankfurt Horizontal plane (2.2 ± 2.0; p = 0.001), respectively. In controls, VOL_postop (9749 ± 3654 mm³) was also significantly higher than VOL_preop (8473 ± 2624 mm³; p = 0.050). Cross-sectional areas, nasal flow and nasal resistance changed significantly after surgery in cases (6/30 pairs; p < 0.018), but not in controls (all p > 0.066). MAX_ADV + IMP increased nasal patency, but did not change the feeling of nasal breathing. Physicians should proceed with caution when informing patients about improvement of nasal breathing after MAX_ADV + IMP.     

Twin-block功能矫治联合固定矫治对安氏II类患者骨性指标及牙（牙合）指标的影响

目的 探究Twin-block功能矫治联合固定矫治对安氏Ⅱ类患者骨性指标及牙(牙合)指标的影响。方法 选取我院自2017年6月至2020年12月期间收治的53例安氏Ⅱ类患者为研究对象，按照随机数字表法分为观察组和对照组，对照组（n=26）给予常规固定矫治治疗，观察组（n=27）在对照组基础上加以Twin-block功能矫治治疗，比较两组的面颌骨组织矫治效果、牙(牙合)矫治效果、气道改善效果、矫治时间及随访复发情况。结果 两组患者FH-NPo、Go-Me、Ar-Go、N-Me、S-Go、SNB、IMPA、NLA值均显著增大（P <0.05）,SNA、ANB、U1-NA、L1-MP值均显著减小（P <0.05），患儿PAR指数各指标评分及总分均显著降低（P <0.05），气道体积与气道横截面积均显著增加（P <0.05），且观察组上述矫治指标改善显著优于对照组（P <0.05）；观察组平均矫治时间显著低于对照组（t=3.925,P <0.05）。结论Twin-block功能矫治联合固定矫治可显著改善安氏Ⅱ类患者面颌部骨组织发育，促进牙齿正常建(牙合)，扩...