【作者】 佟玲；

【导师】 刘淑杰；

【作者基本信息】 中国医科大学 ， 口腔临床医学， 2002， 硕士

【摘要】 前言 龋病是一种危害人类健康的，感染性、可传播性疾病，其主要致病菌为变形链球菌(mutans streptococci，简称MS)。远缘链球菌(Streptococci sobrinus，简称SS)是变形链球菌属中的一种，也与人类龋病密切相关。近年来国外一些学者对MS在儿童口腔内的定居时间和影响定居的因素进行了研究，但对MS的最早定居时间尚存在争议。国内仅邱文彦对MS在婴幼儿定居时间进行了研究，而对影响变形链球菌定居的因素及远缘链球菌的定居时间尚未见报导。因此确定MS在儿童口腔内最早定居时间及影响定居的因素，将有助于阻断或延迟MS的定居和传播，从而预防和延缓龋病的发生。本实验在国内首次对变形链球菌在婴幼儿牙面上定居的影响因素及远缘链球菌的定居时间进行了研究，并为制定婴幼儿的防龋计划提供可靠依据。 材料与方法 随机选取沈阳市儿童医院地段定期接种疫苗和身体检查的6-24个月的儿童，按年龄分为6组各30名，共180例，其中男孩90例，女孩90例。 对儿童的母亲180例(年龄在24-31岁)采样的同时进行问卷调查。受检儿童和母亲均无系统性疾病，采样前2周内未使用任何抗生素类药物。采样均在上午8-9时进行，取样前晨起儿童及母亲不刷牙不漱口。采取上颌前牙唇面颈1/3处菌斑(无牙齿萌出和无法取牙菌斑的儿童用消毒的滴管吸取舌下唾液)和母亲的唾液放人硫乙醇酸钠转送液的样本瓶内，用转运保温瓶带回实验室。实验由同一检查者完成。样品在微量震荡器上震荡30秒后，菌斑和唾液样本用转送液连续稀释10－‘上0＼10－’后，分别取50卜1稀释液接种于TY“3培养基上，在37℃条件下厌氧培养始小时后，进行次代培养，获得纯培养做生化实验以及产 Hp。实验鉴定变形链球菌。采用计算机SPSS／PC”统计分析进行数据处理。 实验结 果 1、180例受检儿童中，99例口腔内检查出 MS，检出率为 55．0％。MS最早定居时间为8个月，MS的检出率随年龄的增长和牙齿萌出的增多而增高，各组间MS阳性率具有显著性差异（X’＝17．40，P＜0．01）。 2＊ 例儿童中，80例检出MS定居；6例检出SSJ 例同时检出MS和SS；75名未检测出MS和SS。SS最早定居时间为8个月，F＝7．21，P＜O．01。同时存在＊S和SS的儿童变链定居时间较只有＊S的定居时间早河＜O．01人 3、MS定居时间与母亲的MS水平及龋齿相关，母亲MS水平越高，其孩子MS定居时间越早。母亲有龋齿其孩子MS定居时间较早（x’＝52．5，P＜0．01）。 4＊童MS定居时间与儿童断奶时间相关，断奶时间超过12个月的儿童较6－12个月断奶的儿童 MS定居时间早（x‘＝39．22，P＜O．01），较6个月以内断奶的儿童＊S定居时间早（／＝49．42，P＜0．001）。 5＊童MS定居时间与喂养方式相关。人工喂养较混合喂养的儿童 MS定居时间早（X’＝7．62，P＜0．01厂也比母乳喂养的儿童 MS定居时间早h‘＝35．27，P＜0．of人混合喂养较母乳喂养的 ·2·儿童MS定居时间早（X‘二I7．95，P＜0刀1）。 6＊童MS定居时间与夜间进食次数相关。夜间进食3次以上的儿童较进食次数在3次以下的儿童MS定居时间早，两者有显著差异（X’＝53．1，P＜0．01）。 7＊童MS定居时间与人睡习惯相关。含奶瓶或乳头人睡的儿童MS定居时间较不含奶瓶或乳头的儿童定居时间早＊’＝15．3，P＜0．01）。 讨 论 一、变形链球菌的定居 L删S的最早定居时间 一些学者认为婴幼儿在乳牙末萌出前检测不到MS州S的检出率随着年龄的增长和牙齿的萌出增多而增加；采用MS或MSB培养基的方法检测MS最早定居时间分别为为乳切牙萌出期①．5－1岁人9个月一13个月不等。Caufied等研究结果显示MS的感染存在一个明显的“感染窗口期”＊‘加大w听 nfenfecth订厂人“感染窗口期”是指MS大量定植的时间。婴幼儿“感染窗口期”为26个月左右，且其中75％在19－23个月期间MS开始增殖。国内学者邱文彦等采用是菌斑接种在含有杆菌肽的变形链球菌选择培养基上的方法检测MS最早定居时间为9个月，“感染窗口期”为13－24个月。 本研究采用样本接种在TYCSB培养基上37℃条件下厌氧培养48小时的方法检测MS定居时间。发现婴幼儿在乳牙未萌出前检测不到MS川S的检出率随着年龄的增长和牙齿萌出增多而增加。180例儿童中有99例口腔内检出MS，检出率为55．0％，且其中75％在14－24个月期间MS开始增殖周S最早定居时间为8个月。 ·3· 入远缘链球菌的定居 远缘链球菌（StrePtococci sohrinus，简称SS）是变形链球菌属中的一种，也与人类龋病密切相关。近来的研究资料表明／S致龋性与龋病的活跃性密切相关。本研究首次对SS在婴幼儿牙面最早定居时间进行研究，结果显示180例儿童中，80例检出MS定居；6例检出SS定居；19例同时检出MS和SS；75例未检测出MS和 SS。SS最早定居时间为 8个月。同时存?更多还原

【Abstract】 Caries is harm for the health of human. It is infection and transmission disease. Mutans streptococci (MS) is main bacteria causing caries. In the present study, the time of colonization by MS and effect factors in children have been investigated and argued in the prime time. In national, there has not news of effected colonization by SS and MS’s factors in children. So to study of colonization of Mutans Streptococci and effect factors in infants would be help of interdiction or delay the colonization and transmission of MS. The hope for containing the caries problem are provided in children.Materials and MethodsOne hundred and eighty children ( age range 6-24 months) from Shenyang city were examined for the colonization of MS and SS. They were divided into six groups according to age. Their mother were also examined and completed questionnaires. They have no system diease and havent taken any antibiotics in two weeks ago. All these exam explorer by one dentist. The saliva samples were transported to the labo-ratory in an anaerobic jar and immediately placed in an anaerobic glove box. Apliquots of undiluted and 1/10 and 1/100 and 1/1000 diluted saliva samples over plated on TYCSB agar plates. The plates were incubated at 37癈 for 48 - hour in an anaerobic glove box( 10% H2,10%CO2,80%N2). Colonies were identified as MS by fermentation test and H2O2test. DP is by SPSS statistical analyses.Results1. Of the 180 infants, 99(55.0% ) had colonization of MS. The prime time of colonization is 8 months, detection rate increased along with the manifold of age and teeth erupted. There were significant differences in the baselin values for six groups (x2 = 17. 40, P < 0. 01).2. The prime time of SS - colonization is 8 months. Of the 180 infants, the 75 children who MS and SS were not detected in infants, the 80 children who only MS were detected, the 6 children who only SS were detected, the 19 children who MS and SS were detected. The children who harbored both MS and SS were earlier detected than only colonization of MS ( P < 0. 01).3. The study showed a correlation between the prime time of colonization and the MS level of his mother.4. The study showed a correlation between the prime time of colonization and feeding mode, breastfeeding, feeding frequency during bedtime, asleep habits.DiscussionMany investigators have reported that MS were not detected before teeth erupted; detection rate increased along with the manifold of age and teeth erupted . The results of the present study support these findings. Using MS or MSB plate, the prime time of colonization is 6 - 13 months. The results of the present study is that the prime time of colonization is 8 months, there were significant differences in the baselin values for six groups(x2 = 17.40,P <0.01).Streptococci sobrinus ( SS) is one of Mantus Streptococci, it is correlation with caries . The results of the present study is that the prime time of SS - colonization is 8 months. Of the 180 infants, the 75 children who MS and SS were not detected in infants, the 80 children who only MS were detected, the 6 children who only SS were detected, the 19 children who MS and SS were detected. The children who harbored both MS and SS were earlier detected than only colonization of MS (P<0.01).Several studies have shown identical MS in mother and child indicating mother is the main source of MS to her child. There is a correlation between the prime time of colonization or caries in child and the MS level of his mother; A correlation between the development of nursing caries and improper feeding habits. The results of the present study is agree with it. The study showed a correlation between the prime time of colonization and feeding mode, breastfeeding, feeding frequency during bedtime, asleep habits.Therefore we take methods that to reduce the level of mother "MS by preventive, to advocate reasonable feeding mode and asleep habits,these would interdice or delay MSs colonization and transmission and decrease caries.Con更多还原