Changes in periodontal pulsation in relation to increasing loads on rat molars and to blood pressure

Pulsation originating from the vascular system of the periodontal ligament (PDL) is apparently synchronized with the heartbeat. As periodontal pulsation causes pulsatile tooth vibration, it might be possible to evaluate it indirectly by measuring tooth vibration. Periodontal pulsation has been found to be dependent on blood flow and blood pressure in the PDL. Heavy orthodontic force is known to reduce blood flow and decrease the amplitude of the pulsation. The purpose now was to examine (1). the magnitude of the experimental orthodontic force that will impair PDL blood flow; and (2). the differences in the amplitude of pulsation between normal and hypertensive animals. The experiments were performed on 10 Wistar, 10 Dahl S and 10 Dahl R rats. Hypertension was induced in Dahl S rats. The head and maxilla of anaesthetized animals were immobilized. Mesial tipping forces of different loads (0.098-0.882 N) were applied to a molar and periodontal pulsation was measured with a highly sensitive laser displacement meter. The periodontal pulsation at each load resembled a blood-volume pulse wave. Its amplitude began to decrease at a load of 0.588 N in Wistar and Dahl R rats, and at 0.784 N in Dahl S rats. The group with induced hypertension had a significantly larger amplitude than the other two groups when 0.588 N was applied. These results suggest that: (1). periodontal pulsation can indicate a PDL overload; and (2). that systemic blood pressure affects the amplitude of periodontal pulsation during loading.     

牙科焦虑症对心血管病患者拔牙心率及血压增幅的影响

目的 :研究牙科焦虑症 (DA)对心血管病患者拔牙心率及血压增幅的影响 ,为术前进行心理治疗和护理提供指导。方法 :采用改良的牙科焦虑量表 (DAS)对 13 8例心血管病患者拔牙术前的DA进行调查 ,对拔牙全过程进行心电监护 ,对DAS得分与心率及血压增幅的相关关系进行统计学分析。结果 :DAS得分与心率增幅相关系数r =0 .0 2 3 ,P =0 .790 ;与收缩压增幅r =0 .2 17,P =0 .0 11;与舒张压增幅r =0 .177,P =0 .0 3 7。结论 :对于心血管病拔牙患者 ,需要术前进行心理治疗 ,以减轻DA ,避免或减少拔牙时血压升高 ,确保手术的安全。     

MMP1 and MMP20 contribute to tooth agenesis in humans

Objective

Variations in genes that are critical for tooth formation may contribute to the tooth agenesis. MMPs are potential candidate genes for dental alterations based on the roles they play during embryogenesis. The aim of this study was to investigate the possible association between MMP1, MMP3, and MMP20 and tooth agenesis.

Methods

One hundred sixty-seven nuclear families from two different populations were analysed, 116 from Brazil and 51 from Turkey. Probands had at least one congenitally missing tooth. DNA samples were obtained from blood or saliva samples and genotyping was performed using TaqMan chemistry. In addition, Mmp20 was selected for quantitative real-time polymerase chain reaction analysis with SYBR Green I Dye in mouse tooth development.

Results

Associations between tooth agenesis and MMP1 (p = 0.007), and MMP20 (p = 0.03) were found in Brazilian families. In the total dataset, MMP20 continued to be associated with tooth agenesis (p = 0.01). Mmp20 was not expressed during the initial stages of tooth development.

Conclusion

Our findings provide evidence that MMP1 and MMP20 play a role in human tooth agenesis.     

Prevalence of delayed tooth development and its relation to tooth agenesis in Korean children

ObjectiveThe aim of this study was to investigate the epidemiology of delayed tooth development (DTD) and the link between DTD and tooth agenesis (TA).DesignThe dental maturity of all of the developing permanent teeth of 4611 children (2417 males and 2194 females) was evaluated from panoramic radiographs. The prevalence of DTD and TA was analyzed, and gender difference for DTS and TA was investigated. The correlation of DTD and TA was investigated in intra-fields and inter-fields.ResultsThe total prevalence of DTD among the 4611 children was 3.40%. The maxillary second premolar was the most frequently delayed tooth (1.02%), followed by the maxillary second molar (0.88%) and the mandibular second premolar (0.74%). DTD significantly correlated with TA in both intra-fields and inter-fields (p < 0.05).ConclusionsThe field of delayed development exhibited a significant correlation with that of TA.     

Development of a three-dimensional in vitro model system to study orthodontic tooth movement

Few three-dimensional (3-D) models exist to study the cellular aspects and molecular regulation of orthodontic tooth movement (OTM). The aim of this study was to develop a 3-D in vitro model to study mechanical loading of human periodontal ligament (PDL) fibroblasts (hPDLF). hPDLF were seeded within collagen gels to form a PDLF analogue. Characterisation of the seeded collagen gels revealed that the gels supported cell proliferation, viability and the emergence of a possible contractile phenotype, replicating the constrained condition of the human PDL in vivo. We next developed a 3-D model that incorporated a seeded collagen gel interlocked mechanically at two ends to movable end plates. The movable end plates allowed for static tensile or compressive loading of the hPDLF-seeded collagen gels. Preliminary testings showed that this 3-D model mimicked PDL strains similar to those observed during OTM. Our 3-D model of OTM therefore offers promise for use as a model system in future studies to improve our understanding of the effects of OTM on PDLF.     

Effects of sympathetic nerve activity on changes in the position of the rabbit incisor tooth evoked by acute alterations in arterial blood pressure

The influence of the sympathetic innervation of periodontal blood vessels on the responses of the upper incisor tooth to sudden changes in mean arterial pressure was studied in 15 anaesthetized rabbits. Changes in axial position of the tooth were measured by ultrasonic transit time technique. With intact sympathetic nerves, the tooth showed small, if any, intrusive movements in response to 6-42 mm Hg reductions in arterial pressure evoked by stimulation of the aortic baroreceptor nerve. When exposed to similar periods of hypovolaemic hypotension, the intrusions were, on an average, 1 micron larger (p less than 0.01). After bilateral sectioning of the cervical sympathetic nerves, tooth intrusions in response to both types of pressure reduction became more marked, as did the extrusive movements evoked by abrupt increases in aortic pressure (produced by inflation of intra-aortic balloon). After sympathectomy, a 19 +/- 6 mm Hg rise in pressure caused extrusions of 6 +/- 3 microns, or 2 microns more than before the sympathectomy (p less than 0.01). The results suggest that the activity in sympathetic nerves to periodontal blood vessels may be inhibited by central nervous mechanisms and that the sympathetic innervation of the periodontal vasculature serves to minimize changes in tooth position brought on by sudden alterations in arterial pressure.     

Spacing in deciduous dentition of Polish children in relation to tooth size and dental arch dimensions

Aim

To assess the prevalence of primary and secondary spacing in the deciduous dentition and its correlation to tooth widths and dental arch dimensions.

Subjects and methods

Dental casts of 50 preschool children free from malocclusion, were analysed. The width of each space was measured as the smallest distance between the proximal surfaces of the neighbouring teeth, parallel to the occlusal plane. Crown width was measured as the greatest distance between the mesial and distal surfaces of the crown, parallel to the occlusal plane. Intercanine widths were measured between cusp tips of upper and lower canines. Intermolar widths were measured between the central fossae of the second molars. Arch lengths were measured from the midpoint between the central incisors to the midpoint between the distal surfaces of the deciduous second molars.

Results

The primary spaces were present in the upper dental arch in 90% children, on the average 2.09 mm in maxilla and 1.25 mm in mandible. Their widths were dependent on upper intercanine width. Secondary spacing was present in 92% children in the upper dental arch (mean 2.86 mm) and 90% in the lower (mean 3.08 mm). Lower secondary spacing was correlated to lower intercanine width and lower arch length. Total absence of interdental spacing was found in 4% children.

Conclusions

Interdental spacing of the deciduous dentition is present in 96% of Polish children. Children with wider intercanine widths have wider primary spaces in maxilla and wider secondary spaces in mandible.     

Alterations in blood pressure and pulse rate in exodontia patients*

The measurement of blood pressure and pulse rate prior to, during and after exodontia was conducted on 60 healthy patients. The aims were to first, investigate the changes in blood pressure and pulse rate, and second, to observe the presence of any clinically significant change over time. Thirty patients attending an Oral Medicine Clinic were used as the control group to allow a comparison to be made between the effects of exodontia and non-invasive treatment. The results suggested that exodontia was the most stressful part of the procedure. Bradycardia during local analgesia was also noted. These changes in the cardiovascular parameters may represent a risk to patients with heart diseases especially those previously undiagnosed. Further, the results indicate the effect stress can have on the cardiovascular system and the importance of eliminating pain and minimizing patient anxiety.     

Dose-response effects of adrenergic drugs on axial movements of the rat mandibular incisor and on arterial blood pressure

Axial tooth movements and arterial blood pressure were measured following the intravenous injection of 0, 0.01, 0.1, 1, or 10 μg/kg of adrenaline, noradrenaline or isoprenaline. Adrenaline caused a dose-dependent, rapid, extrusive tooth movement with a nearly simultaneous increase in blood pressure, followed by a marked intrusive tooth movement and a decrease in blood pressure. Noradrenaline caused a dose-dependent, rapid, extrusive tooth movement and an increase in blood pressure, but a subsequent intrusive tooth movement and decrease in blood pressure were not so marked. Isoprenaline caused a marked intrusive tooth movement and a decrease in blood pressure, without an extrusive tooth movement and increase in blood pressure. The time required to reach the maximum intrusive tooth movement was delayed after that to reach the maximum decrease in blood pressure. The recovery time of the intrusive tooth movement was much more delayed than that of blood pressure. These results suggest that the extrusive movement of the rat incisor was primarily related to the rise of arterial blood pressure due to stimulation of vascular -receptors. It is also suggested that stimulation of ß-receptors would probably cause vasodilatation of arteries that would make the pressure in the small vessels in the microcirculation of the socket fall, so reducing the volume of blood and interstitial fluid in the socket followed by a marked and continuing intrusive tooth movement.     

Changes in masseter muscle blood flow during voluntary isometric contraction in humans

The effect of jaw clenching on local blood flow in the masseter muscle was measured using the hydrogen clearance method in 13 healthy subjects. Sustained isometric masseter-muscle contraction levels of 25 and 50% of maximum voluntary contraction (MVC) were investigated. The blood flow at 25% MVC before contraction, during contraction and after contraction was 12.3 +/- 10.9, 19.2 +/- 12.1 and 78.8 +/- 63.9 mL min(-1) (100 g)(-1) (mean +/- s.d.), respectively. At 50% MVC, it was 14.2 +/- 12.9, 18.6 +/- 10.0 and 80.1 +/- 61.8, respectively. The volume of blood flow was significantly greater after contraction as compared with before contraction at both levels (P < 0.0001) and there was no significant difference between before and during contraction periods (P = 0.17: 25% MVC; P = 0.38: 50% MVC). At 50% MVC blood flow before contraction and the difference in blood flow before and during contraction showed significant negative correlation (r = -0.636, P < 0.02). When the volume of blood flow was low before contraction it tended to increase during contraction and decreased when it was high before contraction. These findings indicate that blood flow in the masseter muscle during sustained isometric contraction is affected by the condition of contraction and may be influenced by the muscle region. It was also indicated that the blood flow during high level contraction was influenced by the volume of blood flow before contraction. Clinically, our findings may help to understand pathological changes which may lead to chronic masticatory muscle pain.     

老年心血管病患者监护拔牙心肌耗氧量及舒张压的监测结果分析

目的：对老年心血管病患者在口腔科拔牙过程中心肌耗氧量及舒张压的监测结果进行分析研究。方法：监测257例患有心血管疾病的老年患者在门诊拔牙过程中心率（HR）、血压（BP）的变化,将能间接反应心肌耗氧量的心率动脉收缩压乘积（Cardiacrate-pressure product RPP）及舒张压在术前、麻药注射中、麻药注射后、拔牙术中、拔牙术后的结果进行统计,分析两者在拔牙各阶段的变化。结果：心肌耗氧量及舒张压在拔牙过程的不同阶段有显著差异。结论：在老年心血管病患者拔牙全程监测心率血压变化,采取各种手段控制血压及心肌耗氧量能有效降低拔牙手术风险。     

Dimensional alterations of the gingiva related to changes of facial/lingual tooth position in permanent anterior teeth of children

Abstract Maxillary and mandibular anterior permanent teeth in 38 children aged 7–12 years were examined 2 × with an interval of 2 years to determine whether spontaneous facial/lingual tooth position changes were related to alterations of the widths of keratinized and attached gingiva and the clinical crown height. Measurements included dental plaque, gingival inflammation, probing depth, and width of keratinized and attached gingiva. In addition, study casts from the baseline and 2-year examinations were used to measure clinical crown height and tooth position. The results showed that significant alterations in the widths of the keratinized and attached gingiva took place when the teeth changed positions in facial or lingual directions. The changes in gingival widths could to some extent be coupled to changes in clinical crown height. In teeth moving lingually, the gingival widths increased and the clinical crown height decreased. In teeth moving facially, the gingival widths decreased, and the facial gingiva sometimes receded. These gingival alterations call for examination of the facial gingiva as part of the monitoring of the development of the permanent dentition.     

0～6岁唇腭裂患儿血液生化指标的变化规律

目的 探索唇腭裂患儿可耐受唇腭裂手术的相对安全生化值,为尽可能多的唇腭裂患儿适时开展手术治疗,保证患儿可以达到序列治疗的最佳效果.方法 回顾分析了已安全完成唇腭裂修复手术的985例患儿的术前多项生化值,用多种医学统计分析的方法进行交叉对比.结果 患儿的总胆红素、直接胆红素、间接胆红素、白蛋白和肌酐及淋巴细胞和红细胞的95％参考值范围完全包含在标准参考值内,白细胞、血小板、血浆白蛋白和球蛋白的比值(简称白球比)、丙氨酸氨基转移酶(ALT)和天冬氨酸氨基转移酶(AST)的95％参考值范围较标准参考值高,血红蛋白、总蛋白、球蛋白和尿素95％参考值范围较标准参考值低;唇腭裂患儿各性别组间血红蛋白、总蛋白、白蛋白、球蛋白和尿素的差异有统计学意义,女性患儿的这些数值要普遍高于男性患儿;单纯唇裂患儿的红细胞、血红蛋白、总蛋白、球蛋白、尿素和肌酐均高于单纯腭裂患儿和唇腭裂患儿;唇腭裂患儿的淋巴细胞、总胆红素、直接胆红素、间接胆红素、ALT和AST均高于单纯腭裂患儿和单纯唇裂患儿.结论 唇腭裂患儿的白细胞、血小板、淋巴细胞、白球比、ALT和AST可能较标准参考值偏高,医生在作术前评估时,可以参考本研究结果,作为开展唇腭裂手术的相对安全指标,以避免错过患儿的最佳手术期,但同时也要更加留意其相关风险性.     

Concentrations of blood, serum and urine components in relation to number of amalgam tooth fillings in Swedish women

Abstract Altogether 1462 women aged 38, 46, 50, 54 and 60 yr were examined in 1968/69 in a combined medical and denial population study in Gothenburg, Sweden. Number of tooth surfaces restored with amalgam fillings was assessed. The examination was repealed in 1980/81 including a new dental examination. The results from a number of biochemical analyses of blood, serum and urine were analyzed for a possible statistical relationship to number of denial amalgam fillings. As emphasis has been put in the literature on special influence from amalgam on kidney function and on the immunological system, special attention was paid to variables which might reflect these functions in our analyses. When potential con-founders were taken into consideration, no significant correlations remained which seemed to be of clinical importance. Specifically, amalgam fillings were not found to be associated with impairment of the kidney function or the immunological status.     

Canceling dental procedures due to elevated blood pressure: Is it appropriate?

BackgroundIn 1974, the American Dental Association first considered recommending that dental offices measure blood pressure (BP) routinely, and it has been further encouraged since 2006. Investigators in several dental publications have recommended cancellation of dental procedures based solely on BP greater than 180/110 millimeters of mercury for urgent oral health care and greater than 160/100 mm Hg for elective oral health care, in the absence of prior medical consultation.MethodsThe authors reviewed the evidence for cancellation of any dental or surgical procedures by using an Ovid MEDLINE search for the terms dental, elevated blood pressure, and hypertension. In addition, the authors searched resources at ebd.ada.org using the same criteria. The authors collaborated to develop recommendations in view of 2017 guidelines on this subject.ResultsTo the authors’ knowledge, there are no professionally accepted criteria or study evidence indicating a specific BP elevation at which to prohibit oral health care. Researchers of a 2015 review on management of comorbidities in ambulatory anesthesia failed to find increased morbidity from hypertension in the outpatient setting.ConclusionsTo the authors’ knowledge, there are no prospective study investigators that have addressed whether or when to cancel dental procedures due to office-measured elevated BP. The authors recommend using current anesthesiology guidelines based on functional status and past BP measurements to prevent unnecessary cancellations.Practical ImplicationsIt is seldom necessary to cancel dental procedures on the basis of BP measured before a planned procedure for patients under a physician’s care.     

颈外动脉分支远心残端动脉压测定及其逆行供血滋养游离皮瓣的可行性探讨

目的 :探讨颈外动脉分支血管远心残端逆行供血滋养游离皮瓣的可行性。方法 :在颈外动脉分支血管甲状腺上动脉、舌动脉、面动脉和颞浅动脉置管,连接压力传感器,采用飞利浦监护仪分别测定各分支血管的初始平均动脉压(MAP)和阻断血流后远心残端MAP,初始MAP与残端MAP之比为残端动脉压比值。以文献记载最先成功开展逆行供血模式游离皮瓣的下肢血管残端动脉压比值为参照,分析颈外动脉分支血管远心残端动脉压比值及其驱动游离皮瓣循环的可靠性。结果:本组颈外动脉各分支血管的远心残端动脉压比值均达到70%以上,大于文献记载的下肢血管的远心残端动脉压比值。结论:颈外动脉分支血管阻断后,远心残端可维持足够残端动脉压,逆行供血滋养游离皮瓣具有可行性。