| Malocclusion is defined as any deviation from the normal arrangement of teeth, and generally occurs in a variety of people. The prevalence of malocclusion is high. According to reports, malocclusion prevalence of children and adolescents is 67.8% in our country, 75.0% in American, more than 70% in Kuwaitis, and 17% to 53% in Swedish. Therefore, the number of patients who need orthodontic treatment is very large, and increases gradually in most countries. The fixed appliance becomes the most frequently-used device in recent decades all over the world due to such traits as good retention, adequate anchorage, effective tooth movement control. Because fixed appliance is adhered to the tooth surface and can not be removed by patients, food scraps are gathered and adhered to tooth and appliances easily if the patients can not clean it very well. This results in an increase of calculus and debris, and then easily leads to gingivitis, periodontitis, enamel demineralization and other complications, which damages dental and periodontal tissues and affect the health and appearance of the teeth. Foreign literature reports that up to 97% of the patients treated with fixed appliances had white spot lesions after therapy. Once this situation appears, it will be attributed to inadequate brushing time and incorrect brushing methods by orthodontists. Then, if patients adopt proper brushing method during fixed orthodontic treatment, what extent the condition of oral hygiene will be controlled to? Is it necessary to add auxiliary measures to control oral hygiene? Is there any stagnant areas for the oral hygiene maintenance? In this study, it was investigated whether the oral hygiene in fixed orthodontic patients could be maintained as well as in non-orthodontic individuals with modified BASS technique by analyzing the oral hygiene differences between them. It was also analyzed whether auxiliary measures should be applied for fixed orthodontic patients. By analyzing the difference of oral hygiene among different teeth, it was investigated whether there were any stagnant areas for the oral hygiene maintenance in fixed orthodontic patients. And by s analyzing the difference of oral hygiene between the orthodontic patients with conventional brackets or self-ligating brackets, it was investigated whether self-ligating brackets should benefit the maintenance of oral hygiene.This thesis consists of three parts:PartⅠ: The clinical controlled trial on the effect differences of modified BASS technique on oral hygiene maintance between fixed orthodontic patients and non-orthodontic individuals.Objective: By observing the characteristics of oral hygiene maintance changing over time with modified BASS technique for orthodontic patients and non-orthodontic individuals, analyze the effect of oral hygiene maintance to study whether the orthodontic patients could achieve the same oral hygiene condition as the non-orthodontic individuals and whether auxiliary measures should be added for patients with orthodontic treatment.Methods: 26 people without orthodontic treatment and 48 patients undergoing orthodontic treatment were sampled. The orthodontic patients were subdivided into self-ligating brackets group and conventional brackets group. All the subjects were guided to use modified BASS technique to maintain oral hygiene. The DI and PLI of teeth on the buccal area and the CI on the lingual area were examined seven days(T1) after scaling and one month(T2), three months(T3), six months(T4) and nine months(T5) latter. The differences of DI, PLI and CI among every groups were investigated.Results: In the terms of plaque and debris, all of the teeth of control group remained substantially the baseline level of debris and plaque after scaling in the nine-month observation period(P > 0.05). For the orthodontic patients, whether conventional group or self-ligating group, the teeth except maxillary lateral incisor and canine and mandibular anterior teeth remained substantially the baseline level of debris and plaque after scaling in the nine-month observation period(P > 0.05), and there was no significant difference with control group(P > 0.05); but it was found that there were significant higher DI and PLI values in upper lateral incisors and canines and mandibular anterior teeth at T2 time, compared with T1 time(P < 0.05), and higher than the same period in the control group of individuals(P < 0.05), which condition did not continue to increase at T3 and T4 time(P > 0.05) but decreased at T5 time(P < 0.05). In the terms of calculus, all the teeth in the maxillary and mandibular canines and posterior teeth of the individuals without orthodontic treatment remained substantially no calculus in the nine-month observation period(P > 0.05), while lingual mandibular incisors and lateral incisors began to build-up after six months but did not increase significantly at T5 time(P > 0.05). All the teeth in the maxillary and mandibular posterior teeth of the orthodontic patients remained substantially no calculus in the nine-month observation period(P > 0.05), while lingual mandibular incisors and lateral incisors began to build-up after one month of treatment which would significantly increase with the extension of treatment time until T4 time(P < 0.05) and lingual mandibular canines began to build-up after six months.Conclusion: In the terms of plaque and debris, modified BASS technique is effective to maintain oral hygiene for the orthodontic patients, and the teeth could be kept in good hygiene condition except upper lateral incisors and canines and mandibular anterior teeth, where should be added auxiliary measures to control oral hygiene more effectively. In the terms of calculus, lingual mandibular incisors and lateral incisors began to build-up after one month of treatment which would significantly increase with the extension of treatment time and this condition gradually extended to the lingual side of the mandibular canine. It suggests that we should always pay attention to the lingual side of t mandibular anterior teeth where the calculus should appear and promptly make the necessary periodontal scaling.PartⅡ: The Comparative Study of Effect of Modified Bass Technique For Oral Hygiene Conditions in Different PartsObjective: To observe the difference of oral hygiene of each tooth in fixed orthodontic patients in order to find stagnant areas of oral hygiene maintenance and guide oral hygiene maintenance in the same dental hygiene maintenance measures(modified BASS technique)Methods: 26 people without orthodontic treatment and 48 patients undergoing orthodontic treatment were sampled. The orthodontic patients were subdivided into SLB group and CB group. All the subjects were guided to use modified BASS technique to maintain oral hygiene. The DI and PLI of teeth on the buccal area and the CI on the lingual area were examined seven days(T1) after scaling and one month(T2),three months(T3), six months(T4) and nine months(T5) latter. The differences of oral hygiene conditions between different teeth were analyzed.Results: For the non-orthodontic individuals, there were no significant differences of the DI and PLI values between different teeth at the examination times of T2-T5(P > 0.05). However, for the two groups of orthodontic patients, it was found that there were significant higher DI and PLI values in upper lateral incisors and canines and mandibular anterior teeth than the other teeth at the examination times of T2-T5(P < 0.05) compared to the other teeth. For the non-orthodontic individuals, there was no significant CI value in the lingual area of all teeth except mandibular incisors and lateral incisors after scaling, which situation was remained in the nine-month observation period(P > 0.05). It was found that there was calculus to begin to gather in the lingual side of lower incisors and lateral incisors of patients with orthodontic treatment at T2 time, where the calculus began to scatter after six months for individuals without orthodontic treatment, and the lingual side of lower canines began to appear calculus at T4 time. The other teeth of orthodontic patients remained no obvious calculus in the nine-month observation period(P > 0.05).Conclusion: In the terms of plaque and debris, there was no significant difference in each tooth for the non-orthdontic individuals. But for the orthodontic patients, because of the application of fixed orthodontic appliance, the upper lateral incisors and canines and mandibular anterior teeth were the stagnant areas of oral hygiene maintance and need to take further measures to strengthen oral hygiene. In the terms of calculus, the lingual side of mandibular anterior teeth began to gather prematurely calculus with respect to the other teeth for orthodontic patients, which situation also existed in individuals without orthodontic treatment. It suggests that we should pay more attention to the lingual side of the mandibular anterior teeth and scale them if necessary.PartⅢ: The clinical controlled trial on the differences of oral hygiene condition between fixed orthodontic patients treated with CB and SLBObjective: To compare and analyze the effect of CB and SLB on oral hygiene with orthodontic patients in the same dental hygiene maintenance measures(modified BASS technique) and the baseline oral hygiene under similar conditions.Methods: 48 patients undergoing orthodontic treatment were sampled, which were divided into CB and SLB groups. All the subjects were guided to use BASS technique to maintain oral hygiene. The debris, plaque and calculus on the buccal area of teeth were examined seven days(T1) after scaling and one month(T2),three months(T3), six months(T4) and nine months(T5) latter. The DI, PLI, CI differences between groups were analyzed.Results: There were no significant DI, PLI, CI difference between CB group and SLB group(P > 0.05) at every examining time.Conclusion: There is no significant advantage for self-ligating brackets on the hygiene maintaining and it suggested that orthodontists could not expect to rely on the use of self-ligating bracket to improve oral health. |
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