Long-period gratings for selective monitoring of loads on a wind turbine blade

An optical fiber sensor based on long-period gratings (LPG) for selective measurements of flap- and edge-wise bending of a wind turbine blade is presented. Two consecutive LPGs separated by 40 mm interfere to improve resolution and reduce noise in a D-shaped fiber. The mode profile of the device was characterized experimentally to provide a model describing the mode couplings. The sensor was tested on a wind turbine blade.

Wound healing of degree III furcation involvements following guided tissue regeneration and/or Emdogain®

BACKGROUND

The use of enamel matrix proteins (EMD) has been recently introduced as a new treatment alternative for periodontal regeneration. However, no histological studies are available investigating the effect of EMD in the treatment of degree III furcation involvements.

OBJECTIVES

The aim of this study was to evaluate the healing of mandibular degree III furcation involvements histologically following treatment with guided tissue regeneration (GTR), EMD and a combination of EMD and GTR.

MATERIAL AND METHODS

Degree III furcation involvements were surgically created at the teeth 36, 37, 46, 47 in three monkeys (Macaca fascicularis). Spontaneous healing of the defects was prevented by placing impression material into the defects. After 6 weeks, full-thickness flaps were elevated at the buccal and lingual aspect of the experimental teeth. Following removal of all granulation tissue from the furcation defects, scaling/root planing and conditioning of the root surfaces with 24% EDTA gel, the defects were treated with one of the following treatment modalities: (i) EMD, (ii) GTR or (iii) a combination of EMD and GTR. The defects serving as control did not receive any treatment, except from complete coverage with coronally displaced flaps. After 5 months of healing, the animals were killed and perfused with 10% buffered formalin for fixation. The experimental teeth with surrounding tissues were dissected free, decalcified in EDTA, dehydrated and embedded in paraffin. 8 microm thick histological sections were cut and stained and subsequently examined under the light microscope.

RESULTS

The histological analysis revealed that with GTR or combined EMD and GTR treatment, new attachment formation (new cementum with inserting collagen fibers) had occurred on almost the entire circumference of the furcation and new bone was almost filling the defect in the situations where the membrane was not exposed. The sites treated only with EMD exhibited new attachment and new bone formation to a varying extent, while the control sites presented only limited new attachment and bone formation.

CONCLUSION

The results provided histological evidence suggesting that both GTR and EMD may result in true periodontal regeneration, and suggest that this type of healing might be favored by such treatments in comparison with flap surgery.

The result of periodontal treatment in relationship to various background factors

The aim of the present study was to investigate whether various background factors of patients play a role for the result of periodontal treatment and whether their attitudes towards prevention change during treatment. The study was carried out as a retrospective analysis using data obtained during periodontal treatment of 143 patients. The result of the treatment was assessed by the recording of presence or absence of gingival bleeding by probing prior to treatment and after 3, 6 and 12 months. The background factors were assessed by letting the patients answer a questionnaire about their dental history, tooth cleaning habits and knowledge about their own dental health situation. Moreover, they responded to statements regarding their attitudes to and general knowledge about prevention of dental diseases. 89 of the patients were asked again 3 months later to respond to these statements. After treatment, 3 groups were formed on the basis of the 12-month gingival score: a successful treatment group (S) comprising 79 patients with a gingival bleeding score of 20% or less, a non-successful treatment group (N) comprising 49 patients with more than 20% tooth surfaces showing bleeding and a drop-out group (D) of 15 patients who did not appear for the 12-month examination. No statistically significant difference was found in the various background factors of patients with a successful or a non-successful treatment result. However, dropping out showed a significant relationship to unfavorable dental beliefs and young age (P less than 0.005). Following treatment, the patients responded more favorably to statements about oral hygiene as a preventive means.

Evaluation of a television-tape demonstration for the reinforcement of oral hygiene instruction

The effect of using a television-tape demonstration in order to reinforce the advice given in a self-teaching oral hygiene program was evaluated in the present study. The teeth of 24 periodontal patients were scaled and 2 weeks later oral hygiene instruction was given by handling out a self-teaching manual. The patients were divided into 2 groups, matched with regard to the initial status of oral cleanliness. An experimental group (TV) comprising 12 patients who, 1 week after the instruction, were shown a demonstration of proper oral hygiene technique on closed circuit television and a control group of 12 patients who did not receive this reinforcement. The presence or absence of dento-gingival plaque and gingival bleeding by gentle probing was recorded initially and after 8 weeks on 4 surfaces of all teeth. In addition, plaque scores were recorded at 2 and 3 weeks to assess the effect of the oral hygiene self-instruction. At the final examination after 8 weeks, the patients with plaque on more than 20% of the tooth surfaces were subjected to a tooth cleaning test including a subsequent scoring of remaining plaque. The patients in the experimental group (TV) were asked their opinion regarding the television-tape demonstration. Although the patients in the experimental group expressed a positive opinion about viewing the television-tape demonstration, the improvement in the plaque and gingival bleeding scores recorded at the 8-week examination showed no difference between the 2 groups of patients. Similarly, the scoring of plaque after the tooth cleaning test showed no difference between the 2 groups.(ABSTRACT TRUNCATED AT 250 WORDS)

The effectiveness of a rotary electric toothbrush on oral cleanliness in adults

The effectiveness of an electric toothbrush (Rota-dent), which in design and mode of action resembles the rotating instruments used by professionals in tooth cleaning, was assessed. 40 adult periodontal patients were divided into 2 groups matched with regard to oral cleanliness: an electric toothbrush group (EB) comprising 20 patients who received an electric toothbrush as well as instruction in it's use by a dental hygienist; a control group (CO) comprising 20 patients who were provided with an oral hygiene kit containing a conventional toothbrush, an interspace brush, toothpicks, disclosing tablets and a lighted mouth mirror and who received the oral hygiene instruction by means of a self-teaching manual. All patients received professional mechanical tooth cleaning 1 week prior to the instruction. At a 3-week follow-up session, additional instruction was given by a dental hygienist according to needs. The presence or absence of dento-gingival plaque after disclosing with the Plak-lite system and gingival bleeding by gentle probing was recorded on 4 tooth surfaces of all teeth, initially and after 3 months. The findings showed a similar improvement in the status of oral hygiene in both groups, indicating that in the hands of the patients, the electric toothbrush was just as effective as the comprehensive oral hygiene kit.

Oral hygiene instruction in general dental practice by means of self-teaching manuals

The present study evaluates the applicability of delivering oral hygiene instruction to patients in general dental practice by means of self-educational programs. Patients (55) seeking dental treatment in 3 general dental practices in Denmark were divided at random into a conventional professional instruction group (C) in which each individual received personal instruction by the dentist and a self-instruction group (S), in which the patients were given self-educational programs. In order to evaluate the effect of the 2 types of instruction, the presence or absence of dento-gingival plaque and gingival bleeding by probing was recorded prior to the instruction and after 3 and 6 months. The patient of the self-instruction group (S) answered a questionnaire about the treatment 1 week after they had received the self-instruction program. An identical improvement in oral hygiene and gingival health was recorded in both treatment groups after 3 and 6 months. This finding indicates, that the self-educational programs were as effective in changing the oral hygiene habits of the patients as was personal oral hygiene instruction by dental personnel. The answers of the patients to the post-treatment questionnaire reflected a favorable attitude towards the use of self-educational programs.

Oral cleanliness and gingival health following oral hygiene instruction by self-educational programs

The aim of the present study was to determine the motivational effect of using a periodontal self-examination manual prior to a self-instructional manual in oral hygiene and to examine whether instruction provided at a later time than the scaling procedure improves the effect of the instruction. 74 patients with periodontal disease were divided into 3 groups: (1) A group of 23 patients who performed a self-examination of their periodontal condition prior to self-instruction in oral hygiene; (2) a control group of 27 patients who used only the self-instructional oral hygiene manual; and (3) a group of 24 patients who were not given the self-instructional oral hygiene manual before 6 weeks after the baseline examination. All these patients had their teeth scaled at the start of the study and after 3 and 7 months. The effect of the various modes of instruction was evaluated by assessments of plaque and gingival bleeding scores. These parameters were determined at the baseline and after 2 and 6 weeks and 3 and 7 months. The results demonstrated a significant improvement in plaque and gingival bleeding scores following the use of the self-instructional manual in oral hygiene. The use of the periodontal self-examination manual or a delay of the instruction had no additional effect on oral cleanliness. The level of oral hygiene and gingival health achieved at 3 months was maintained in all 3 groups for an additional period of 4 months. After that time, they were divided into 2 other groups depending on whether or not their plaque score was less than 20%. A total of 26 in the group who had a plaque score higher than 20% demonstrated a plaque score of than 20% after having performed the tooth brushing test. 10 of the remaining patients, who still had a plaque score of more than 20% after the tooth brushing test, received additional instruction in oral hygiene which subsequently resulted in improved oral cleanliness after 6 months.

Evaluation of various feedback mechanisms in relation to compliance by adult patients with oral home care instructions

The purpose of the present study was to examine the effect on oral hygiene and gingival health of plaque scoring and the performance of a 'tooth brushing test" at each visit during initial periodontal treatment. A total of 63 adult periodontal patients (22-67 years of age) was allocated to 4 matched groups: Brushing test group (B), open scoring group (O), minimal feedback group (M) and control group (C). The oral hygiene instruction for groups B, O and M was provided by handing out a self-educational manual on oral home care, while the patients of control group (C) received a short brochure describing the Bass brushing technique and the use of toothpicks. Feedback on the improvement of oral hygiene performance was delivered to groups B and O by scoring of plaque and gingival bleeding by probing while this feedback was avoided in the 2 other groups (M, C). The patients of group B performed a tooth brushing test at each of 3 visits. After 3 months the plaque scores of groups B (27%) and O (22%) had improved more than those of the 2 other groups (35%). However, the improvement in gingival bleeding scores was similar in all 4 groups (from 55% initially to 17% at 3 months). At later examinations only minor differences in plaque and gingival bleeding scores were recorded between the various groups. The findings show that, irrespective of the mode of instruction, a considerable improvement occurs and that this improvement is not related to open scoring of plaque or the tooth brushing test.

Oral hygiene instruction of adults by means of a self-instructional manual

The need for improved oral cleanliness in adults presents a large scale resource requirement for professional manpower if oral hygiene instruction is to be accomplished conventionally on an individual basis at the chairside. Therefore a self-instructional manual in oral hygiene measures, to be used by the patients at home, has been designed. The effect on oral hygiene of periodontal patients following instruction by means of this manual has been compared with the effect of one instruction carried out by a dental hygienist as well as with the effect of minimal instruction by the aid of a short brochure. Thirty-seven patients (25--64 years of age) were allocated to three groups matched with regard to baseline scores of dento-gingival plaque, age and sex. Presence of disclosed dento-gingival plaque (Plak-lite) and gingival bleeding on probing were recorded at the start, 1, 2 and 6 weeks, 3 and 6 months. Toothbrushing performance of the patients was evaluated at each visit by a "brushing test". The treatment of all the patients consisted of scaling and polishing of the teeth at the start and after 3 months as well as the patients being supplied with the necessary oral hygiene aids including a lighted mouth mirror, a toothbrush, toothpicks and disclosing tablets. The baseline mean plaque and bleeding scores of 64 and 40% decreased during the first 6 weeks to a level of 20 and 14%. This improvement was maintained during the 6-month study period. Among the three groups no significant differences were observed in oral hygiene and gingival health. The results indicate that an oral hygiene instructional mode relatively independent of professional manpower may be equally effective as one single personal instruction. Furthermore the results suggest that factors other than the instruction per se are important for obtaining improvements in oral home care.

Interproximal periodontal intrabony defects. Prevalence, localization and etiological factors

The purpose of the present investigation was to study the distribution of interproximal periodontal intrabony defects as related to age, sex and localization, and to examine the relationship between some possible etiological factors and the occurrence of intrabony defects. A total of 209 adult patients presenting for dental treatment at the Royal Dental College in Arhus participated in this study. The patients were subjected to a questionnaire and were examined clinically and radiographically. All osseous defects in the radiographs were recorded but only those with a depth and width of a least 2 mm were considered periodontal intrabony defects. Only 18% of the participants had one or more periodontal intrabony defects but the prevalence was higher in older than in younger age groups. While periodontal intrabony defects occurred with the same frequency on the various tooth types, more defects were found on distal than on mesial surfaces. The presence of periodontal intrabony defects correlated with loss of attachment, increased tooth mobility, a wide interproximal space and open mesio-distal contact relationships between the teeth.

Periodontal self-examination. A motivational tool in periodontics

The institution of proper oral hygiene procedures and habits is a learning process. This paper describes a self-instructing periodontal self-examination program to be used in the initial phase of periodontal treatment. The program was designed in an effort to facilitate learning by taking the teaching conditions into consideration. The program tries to utilize the patient's curiosity and need for activity and to involve the patient himself in an effort to make the patient apprehend the relevance of subject matter. The program also allows for an individualized learning speed of the patient. The self-examination program was tested on 108 periodontal patients (19-75 years of age) and the patients' findings were compared to those made by a dentist. Questionnaires before and after the self-examination were used in the evaluation of opinions of the patient. The present study showed that the patients were able to perform the self-examination without individual professional guidance. A rather close correlation was noted between findings made by the patient and the dentist. Furthermore, the program was well accepted and appreciated by the patients according to their answers on the questionnaires.

Effect of regular small group instruction per se on oral health status of Danish schoolchildren

A 1-year study of the isolated effect of an intensive motivation program aimed at improving the oral health status of 11-13-year-old schoolchildren was conducted in a Danish provincial town where all children have access to a free and comprehensive school oral health program. The effect was negligible as measured by epidemiologic indices.

Effect of professional toothcleansing every third week on gingivitis and dental caries in children

A previous paper reported on the 1-year effect on dental caries and gingivitis of biweekly professional toothcleansing. The purpose of this study was to evaluate the influence of a change from 2 to 3 weeks in the interval between the professional toothcleansings during the 2nd year. The DMFS increment during the 2nd year did not differe significantly between the experimental and control groups. The plaque and gingival indices, although increased during the 2nd year, were still significantly lower in children subjected to the 3-weekly cleansing than in children in the control group.

Effect of monthly professional mechanical tooth cleaning on periodontal health in adults

The beneficial effects of comprehensive dental prophylaxis programs are well recognized. In order to study the factors determining the effectiveness of these programs, 28 periodontal recall patients were subjected to monthly professional mechanical tooth cleanings. Experimental and control teeth were randomly selected according to a splitmouth cross-over method. The Plaque and Gingival indices were recorded 1 month prior to the study, at the start, and at 4, 8, and 12 months. One month prior to the study calculus and bacterial plaque were thoroughly removed from all teeth. During the study period only the experimental teeth were cleaned. Efforts were made not to influence the oral hygiene of the participants by any other means. Following the initial tooth cleaning and during the preexperimental period the Plaque and Gingival indices decreased to a low level on both the experimental and control teeth (mean P1I = 0.4, mean GI = 0.3). This high standard of oral hygiene and gingival health was maintained throughout the study period, and no differences could be observed between experimental and control teeth. This indicates that factors other than the mechanical professional cleaning were responsible for the maintenance of gingival health. It is suggested that participation in the program in itself may have motivated the patients to improve their oral home care.

The effect of professional toothcleansing on gingivitis and dental caries in children after 1 year

The purpose of this study was to determine the effects of professional mechanical toothcleansing on plaque, gingivitis, and dental caries in young children with a high caries experience. Seventy-eight children, 7 years of age, were stratified according to presence or absence of smooth surface lesions on the permanent teeth and subsequently randomly assigned to an experimental group and a control group. The experimental group was given a thorough mechanical toothcleansing every 2 weeks. After 12 months a statistically significant difference in plaque accumulation and a minor difference in level of gingival inflammation could be demonstrated between the two groups. The incidence of dental caries in permanent teeth present at both examinations was 70% lower in the experimental group. The effect on permanent teeth erupting during the study and on primary teeth present at both examinations was not statistically significant.

Dynamics of dental epithelium during tooth eruption

The dental epithelium of developing rat molars was labeled with tritiated thymidine administered by gastric intubation. Labeled ameloblasts were lost from all enamel surfaces at approximately the same time by desquamation into the gingival sulcus. The other cells of the dental epithelium proliferated to form the renewing epithelial cuff.