气相色谱法测定羟乙基淀粉摩尔取代级

目的:建立一种快速、准确的羟乙基淀粉摩尔取代级测定方法。方法:以氢碘酸水解羟乙基淀粉中的羟乙基成碘乙烷,用气相色谱法测定。色谱柱:CP-Sil 5CB(10％甲基硅酮,25 m ×0.25 mm,膜厚0.4μm),检测器:氢火焰离子化检测器(FID),柱温:100℃,进样器温度:200℃,检测器温度:300℃,载气:N_2,流速:1mL·min~(-1),分流比:1:3O,内标:甲苯,对照品:碘乙烷。结果:方法重现性良好,RSD为2.7％(n=5);回收率为98.2％(n=5)。分析了5批样品,结果与用Zeisel法测定结果基本一致。结论:本方法分离效率高,专属性好,可作为该品种摩尔取代级的测定方法。     

微创技术治疗乳磨牙深龋的疗效评价

目的评价Carisolv化学机械法微创技术用于乳磨牙深龋的治疗效果。方法选择108个乳磨牙深龋,其中58个龋牙采用化学机构法去腐(治疗组),50个龋牙采用传统牙钻去腐(对照组),两组去腐后均采用玻璃离子充填,经过1年观察,比较治疗效果。结果2种治疗方法在修复体的完整性、边缘缺损及脱落等方面均无统计学意义(P>0.05),但X线成功率治疗组明显高于对照组(P<0.05)。结论Carisolv是一种轻柔操作,能消除儿童对牙科的恐惧感,减轻疼痛,减少穿髓等并发症的发生,值得在儿童龋病治疗中推广。     

正畸治疗对安氏II~1错畸形患者下颌旋转与移动的影响

目的:探讨正畸治疗对安氏II1错畸形患者下颌旋转与移动的影响。方法:治疗组20例,非正畸治疗组18例。所有患者均无外科手术治疗史、无拔牙史和功能矫治治疗史。通过头颅侧位片采集患者治疗前、治疗后的头影测量数据进行分析。结果:正畸治疗可诱导安氏II1错!畸形患者的下颌垂直向生长和颏点垂直向移位增加。上颌与下颌磨牙的垂直向或向移动与下颌旋转及颏点的水平向移位无关。与对照组相比,两组之间在上颌磨牙的向移动和下颌旋转方面无显著性差异。结论:正畸治疗影响下颌的垂直向生长及颏点的垂直向移动,而对下颌旋转及上颌磨牙的向移动无明显影响。     

Innervation of the Temporo-Mandibular Disc in Man

Abstract

Objective. To examine whether the rapid increase in the availability of cone-beam computed tomography (CBCT) has changed the number of inferior alveolar nerve (IAN) injuries related to the removal of mandibular third molars in Finland. The hypothesis was that the number of nerve injuries should diminish due to better imaging methods. Materials and methods. The number of CBCT devices, the annual number of CBCT examinations and the number of permanent IAN injuries occurring between 1997 and 2007 were analyzed. The data was collected from three national registers: the Radiation and Nuclear Safety Authority, the Social Insurance Institution and the Patient Insurance Centre. A detailed analysis was made from the cases of permanent IAN injuries. Results. The first CBCT device was registered in 2002 and the cumulative number of these devices in 2009 was 22. There was an increase from 555 to 3160 in the number of annual CBCT examinations during the period 2004–2009. The total number of permanent IAN injuries during the years 1997–2007 was 129 and remained stable throughout the period (regression analysis, p = 0.974, r ² = 0.01). Conclusions. Contrary to this hypothesis, the availability of CBCT devices has had no significant influence on the number of IAN injuries related to mandibular third molar removals in Finland. More education should be given to optimize the use of CBCT to cover difficult cases that may give rise to complications.     

Efficacy of adjuvant ozone therapy in reducing postsurgical complications following impacted mandibular third-molar surgery: A systematic review and meta-analysis

BackgroundResults from several randomized controlled trials have shown a beneficial effect of ozone in reducing postsurgical complications after impacted mandibular third-molar surgery, but the literature is lacking a systematic review and meta-analysis.MethodsThe authors conducted this systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines after exclusion and inclusion criteria were applied and the following outcome parameters were evaluated: pain, swelling, trismus, quality of life, number of analgesics consumed, and adverse events. RevMan Cochrane Collaboration software, Version 5.3, was used to perform meta-analysis and the Grading of Recommendation Assessment, Development and Evaluation approach was used to rate the certainty of evidence.ResultsPatients who underwent adjuvant ozone application reported lower pain scores than patients in the control group at 24 hours after surgery (95% CI, –3.94 to –1.56) and at 7 days (95% CI, –1.67 to –0.78). Pooled analysis of all 4 included trials revealed a standardized mean difference (SMD) in swelling of –0.44 at 24 hours, 0.63 at 72 hours, and –0.87 at 7 days after surgery in the experimental group. Higher mean estimates in mouth opening were experienced by patients who received ozone at 24 hours (SMD, 2.74; 95% CI, –1.93 to 7.41; 4 studies, 133 patients), 72 hours (SMD, 2.77; 95% CI, –0.63 to 6.17; 4 studies, 133 patients), and 7 days after surgery (SMD, 1.42 SMD; 95% CI, –1.34 to 4.18; 4 studies, 133 patients).Practical ImplicationsEvidence suggests that adjuvant ozone application can offer some benefit for reducing pain, improving quality of life, and decreasing mean intake of analgesics after impacted mandibular third-molar surgery, but it is not effective in reducing facial swelling and trismus, which paves the way for future research.     

Piezoelectric bone surgery for impacted lower third molar extraction compared with conventional rotary instruments: a systematic review,meta-analysis,and trial sequential analysis

The aim of this study was to evaluate whether piezoelectric bone surgery (PBS) for impacted lower third molar extraction reduces the surgical time and risk of intra- and postoperative complications in comparison with conventional rotary instruments. This meta-analysis followed the PRISMA guidelines and was registered in the PROSPERO database. The PubMed, Embase, Scopus, and OpenGrey databases were screened for articles published from January 1, 1990 to December 31, 2018. Selection criteria included randomized controlled trials (RCTs) comparing PBS with conventional rotary instruments for impacted lower third molar extraction and reporting any of the clinical outcomes (intra- and postoperative complications and duration of surgery) for both groups. A risk of bias assessment was performed using the Cochrane Collaboration tool. A meta-analysis was performed, and the power of the meta-analytic findings was assessed by trial sequential analysis (TSA). Strong evidence suggests that PBS prolongs the duration of surgery and low evidence suggests that PBS reduces postoperative morbidity (pain and trismus) in comparison with rotary instruments. Data were insufficient to determine whether PBS reduces neurological complications and postoperative swelling in comparison with burs.     

Factors associated with molar incisor hypomineralization in Thai children

Molar incisor hypomineralization (MIH) is a qualitative developmental enamel defect that affects one to four permanent first molars, with or without involvement of permanent incisors. Its etiology is of systemic origin, but is not well understood. Therefore, we conducted this cross‐sectional study to examine pre‐, peri‐, and postnatal risk factors for MIH among children, 7–8 yr of age, in urban areas of Khon Kaen, Thailand. Molar incisor hypomineralization defects were diagnosed using the European Academy of Pediatric Dentistry criteria. Mothers or primary caregivers were interviewed on maternal medical history and habits during pregnancy, pregnancy and delivery complications, and the child's medical history. Molar incisor hypomineralization defects were observed in 78 (27.7%) of 282 children. Multiple logistic regression analysis showed a statistically significant association between the development of MIH and Cesarean section (adjusted OR = 2.0, 95% CI = 1.1–3.7), complications during vaginal delivery (adjusted OR = 4.5, 95% CI = 1.9–11.0), and severe/chronic illness when under 3 yr of age (adjusted OR = 2.9, 95% CI = 1.6–5.0). There was no association of preterm birth and low birth weight with MIH. The results suggest that Cesarean section, complications during vaginal delivery, and poor health during the first 3 yr of life are independent risk factors for MIH.     

First molar cross‐bite is more closely associated with a reverse chewing cycle than anterior or pre‐molar cross‐bite during mastication

A posterior cross‐bite is defined as an abnormal bucco‐lingual relationship between opposing molars, pre‐molars or both in centric occlusion. Although it has been reported that patients with unilateral posterior cross‐bite often show unique chewing patterns, the relationship between the form of cross‐bite and masticatory jaw movement remains unclear in adult patients. The objective of this study was to investigate masticatory jaw movement among different forms of cross‐bite. One hundred and one adults were recruited in this study: 27 had unilateral first molar cross‐bite (MC group); 28, unilateral pre‐molar cross‐bite (PC group); 23, anterior cross‐bite (AC group); and 23, normal occlusion (control group). Masticatory jaw movement of the lower incisor point was recorded with six degrees of freedom jaw‐tracking system during unilateral mastication. Our results showed that the reverse chewing ratio during deliberate unilateral mastication was significantly larger in the MC group than in the PA (P < 0·001), AC (P < 0·001) and control (P < 0·001) groups. These findings suggest that compared to the anterior or pre‐molar cross‐bite, the first molar cross‐bite is more closely associated with a higher prevalence of a reverse chewing cycle.     

A logistic regression model for analyzing the relation between dentists' attitudes,behavior, and knowledge in oral radiology

The aim was to study the relation between risk attitude and knowledge in technical, patient-oriented, and organizationally related behavior within oral radiology. A questionnaire was mailed to 2000 randomly selected dentists listed in the register of the Swedish Dental Society, with a response rate of 69.3%. Regression analysis was used for analyzing the effects of the independent variables knowledge, risk attitude, continuing education in oral radiology, counties with specialists in oral radiology, type of practice, work experience, and sex on three categories of dependent variables: 1) technical behaviors: type of film, type of collimator, dose level, frequency of change of chemicals; 2) patient-oriented behaviors: use of patient protection barriers, strict indications for performing full-mouth X-ray examinations and bitewing radiography on new patients and recall patients; and 3) organizationally related behaviors: delegation of X-ray examinations to dental auxiliaries, influence on choice of collimator, influence on choice of film. Knowledge and education had strong direct effects for most of the dependent variables. The technical behaviors were mainly influenced by knowledge, education, and risk attitude, while organizationally related behaviors were influenced by type of practice and sex. The patient-oriented behaviors were influenced by a number of independent variables, such as education, type of practice, work experience, and sex. The present results indicate that both knowledge and the organizational context of dentists influence work.