Flink Håkan
Department of Cariology, Institute of Odontology Karolinska Institutet, Stockholm, Sweden.
Swed Dent J Suppl. 2007(192):3-50, 2 p preceding table of contents.
Reduced salivary flow is a condition that affects oral health. Its prevalence is unknown in young and middle-aged adults and there is no known treatment that permanently increases the salivary flow rate. Reduced salivary flow is related to dental caries, the most common oral disease. Reduced salivary flow is often found in individuals with insufficient food intake and thereby insufficient nutrition to the salivary glands. One nutrition related factor that has been proposed to effect salivary flow rate is iron deficiency.
The aims of the thesis were to investigate i) the prevalence of reduced salivary flow rate in different age groups of adults, ii) the relationship between reduced salivary flow rate, general health and dental caries, iii) the influence of time of measurement on reduced salivary flow rate, and iv) if reduced salivary flow rates could be increased by iron supplementation.
In Study I saliva was collected from 1427 individuals aged 20-69 years. A questionnaire was answered regarding subjective oral dryness, general diseases, use of drugs, BMI (Body Mass Index) and use of tobacco. In Study II saliva was collected from 48 patients with active caries and 48 caries-inactive patients. A blood sample was analysed for serum ferritin. In Study III the unstimulated salivary flow rate was tested at 7:30 and 11:30 a.m. in 108 individuals, age 15-46 years. The participants were allocated to one of three groups (very low < 0.1 mL/min, low 0.1-0.2 mL/min and normal > 0.2 mL/min) based on the the unstimulated salivary flow rate at 7:30 a.m. Different aspects of the perception of oral dryness were rated using Visual Analogue Scales. In Study IV a double-blind, randomized controlled trial was carried out on 50 individuals with a low unstimulated whole salivary flow rate and low serum ferritin. Half the individuals received 60 mg of iron orally twice a day for 3 months, while the other half received placebo.
In Study I it was found that the prevalence of very low (< 0.1 mL/min) and low (0.10-0.19 mL/min) unstimulated salivary flow rate were similar for different age groups up to 50 years, ranging between 10.9-17.8% and 17.3-22.7%, respectively. Multiple logistic regression revealed that above age 50, female gender, 'having fewer than 20 teeth', and taking xerogenic drugs significantly increased the risk of very low unstimulated salivary flow rate. In Study II 32 individuals (67%) in the caries active group had low unstimulated salivary flow rate compared with 13 individuals (27%) in the caries inactive group. There was no difference in serum ferritin levels between the two groups. Study III showed for all groups a statistically significant increase in unstimulated salivary flow rate at 11:30 a.m. compared with 7:30 a.m., all of similar magnitude (0.08-0.09 mL/min). In the group with very low salivary flow rate, 70% at 11:30 a.m. exceeded the 0.1 mL/min limit. There were significant difference in perception of oral dryness between the normal group and both the low and the very low groups. In Study IV no statistically significant difference was found between the groups after treatment for the unstimulated flow rate and in the subjective assessments of oral dryness.
The prevalence of reduced salivary flow rates is consistent and prevalent in younger and middle-aged adults (< 50 years). Very low salivary flow rates are related to high Body Mass Index (BMI) and diagnosed diseases in younger adults, but to medication in older adults. Reduced salivary flow rate in young adult women is related to caries. The time of measurement of salivary flow rates influences diagnosis of hyposalivation. Iron supplementation does not enhance salivary flow.
唾液分泌减少是一种影响口腔健康的状况。其在中青年成年人中的患病率尚不清楚，且尚无已知的能永久性增加唾液流速的治疗方法。唾液分泌减少与龋齿（最常见的口腔疾病）有关。唾液分泌减少常出现在食物摄入量不足从而唾液腺营养不足的个体中。一种被认为会影响唾液流速的营养相关因素是缺铁。
本论文的目的是研究：i）不同年龄组成年人唾液流速降低的患病率；ii）唾液流速降低、总体健康状况和龋齿之间的关系；iii）测量时间对唾液流速降低的影响；iv）补充铁剂是否能提高降低的唾液流速。
在研究I中，收集了1427名年龄在20 - 69岁个体的唾液。就主观口腔干燥、全身性疾病、药物使用、体重指数（BMI）和烟草使用情况回答了一份问卷。在研究II中，收集了48名患有活动性龋齿患者和48名无龋齿患者的唾液。对一份血样进行血清铁蛋白分析。在研究III中，对108名年龄在15 - 46岁的个体在上午7:30和11:30测试了非刺激性唾液流速。根据上午7:30的非刺激性唾液流速，将参与者分为三组之一（极低<0.1 mL/分钟、低0.1 - 0.2 mL/分钟和正常>0.2 mL/分钟）。使用视觉模拟量表对口腔干燥感觉的不同方面进行评分。在研究IV中，对50名非刺激性全唾液流速低且血清铁蛋白低的个体进行了一项双盲、随机对照试验。一半个体每天口服60毫克铁剂，持续3个月，而另一半接受安慰剂。
在研究I中发现，50岁及以下不同年龄组的极低（<0.1 mL/分钟）和低（0.10 - 0.19 mL/分钟）非刺激性唾液流速患病率相似，分别在10.9 - 17.8%和17.3 - 22.7%之间。多元逻辑回归显示，50岁以上、女性、“牙齿少于20颗”以及服用致口干药物会显著增加极低非刺激性唾液流速的风险。在研究II中，龋齿活动组有32名个体（67%）非刺激性唾液流速低，而无龋齿组有13名个体（27%）。两组之间血清铁蛋白水平无差异。研究III表明，与上午7:30相比，所有组在上午11:30时非刺激性唾液流速均有统计学显著增加，幅度均相似（0.08 - 0.09 mL/分钟）。在极低唾液流速组中，上午11:30时有70%超过了0.1 mL/分钟的限值。正常组与低流速组和极低流速组在口腔干燥感觉方面存在显著差异。在研究IV中，治疗后两组在非刺激性流速和口腔干燥主观评估方面未发现统计学显著差异。
唾液流速降低的患病率在中青年成年人（<50岁）中是持续且普遍的。极低唾液流速在年轻成年人中与高体重指数（BMI）和已诊断疾病有关，但在老年人中与药物治疗有关。年轻成年女性唾液流速降低与龋齿有关。唾液流速的测量时间会影响唾液分泌减少的诊断。补充铁剂不会增加唾液流速。
