Water irrigating devices for the orthodontic patient.

Fixed orthodontic appliances increase the number of retention areas, resulting in increased possibilities for the accumulation of dental plaque. In addition, there is a risk of direct mechanical irritation. In spite of good toothcleaning most orthodontic patients develop generalized moderate gingivitis or an edematous type within one to two months after the placement of the fixed orthodontic appliances. Since the gingival changes represent a reaction to the bacterial plaque products rather than to the orthodontic forces; the only way to control them is by effective oral hygiene. Braces and banded teeth have many tiny recesses that a toothbrush and other cleaning aids have difficulty reaching. For good oral hygiene, these should be kept free of food debris. Water irrigating devices irrigates these hard-to-clean areas to remove food and other debris. Pulsating jets of water very gently lift the free gingiva to rinse out crevices. The water irrigator also pulses into areas between teeth and gums to flush out trapped food and debris. Water irrigating devices cannot by any means be regarded as substitutes for more effective plaque-removing methods, such as tooth-brushing and flossing; rather, they should be considered as an adjunct to the total oral hygiene program.

Soft-tissue profile changes concurrent with the orthodontic treatment.

Anthropologists have shown that the external covering made up of integument, adipose tissue, connective tissue, and muscle does not always distribute itself in a uniform, orderly manner. There are great variations in the amount and distribution of these soft-tissue elements. Therefore, a facial profile analysis that is limited to measurements on the hard skeletal structure would not appear to conform to the standards of accuracy if an assessment of the soft-tissue profile were required. The purpose of this investigation is to provide an understanding of the changes which occur in the soft-tissue profile during the orthodontic treatment concurrent with normal growth and development. At the present time, it is not possible to devise a set rule for differentiating a desireable from an undesireable soft-tissue facial profile. However, this should not prohibit the presentation of some reference material as an aid in the diagnosis and practice of orthodontics. In many instances evaluations of facial esthetics seem to be singularly influenced by the orthodontist's concept of a pleasing face. At present, the accomplishment of soft-tissue profile changes by dental movement is limited so it is very important to rely on proper timing of the orthodontic treatment through the pubertal growth period to achieve optimal profile changes.

Porion and condyle as cephalometric landmarks--an error study.

With the recent increase in the use of functional appliances for orthodontic treatment in which condylar growth plays an important role in the final results, orthodontists and researchers should be aware of the process of growth and development of various components of the skull to see the changes of measurements on cephalometric tracings in different stages of treatment. This study was conducted to assess the reliability of the porion and condyle on the lateral cephalogram. A group of 24 patients was selected randomly from the Orthodontic Department at Tufts University. Two sagittal roentgenograms, one in habitual (centric) occlusion and one with the mouth wide open, were taken. Each cephalogram was traced by two observers to determine discrepancies in tracing the shape and position of the porion and condyle. The Pearson product-moment coefficient of correlation was performed for inter- and intraobserver reliability for locating the porion and condyle in open- and closed-mouth positions. It was concluded that the porion and condyle cannot be located accurately and consistently on sagittal roentgenograms in the closed-mouth position. Therefore it appears advisable to obtain an open-mouth cephalogram and superimpose it onto the respective closed-mouth cephalogram. This will provide greater accuracy and reliability in obtaining cephalometric measurements.

Demineralization potential of different concentrations of gelatinized wheat starch.

Six subjects wore intraoral devices carrying bovine enamel blocks covered with a layer of Streptococcus mutans. They swished solutions of 5% glucose or maltose, or sols or gels of 3, 5, 10, 15, or 20% gelatinized wheat starch in the mouth for 3 X 1 min. Demineralization was measured after 45 min by determining the change in iodide permeability (delta Ip) of the enamel. Spittings of the administered materials and samples of saliva, taken at intervals during the test, were analyzed for maltose, and the time of clearance was calculated. Demineralization was greatest for glucose followed by maltose, the starch gels, and the sols. The latter gave close to zero scores. The salivary clearance time increased with increase in concentration of the starch. Although the starch was hydrolyzed rapidly in the mouth, its oral retentiveness was greater than that of the maltose rinse. Demineralization was closely correlated with the final pH of the S. mutans cell layer. The data indicate that the starch in baked or cooked foods may have a significant demineralization potential and that it enhances oral retentiveness.

The bonded mandibular lingual retainer.

The lower fixed retainer from cuspid to cuspid has been one of the commonly used methods of retention at the end of the orthodontic treatment. Orthodontists mostly use the lingual wire soldered to cuspid bands for the fixed lower retainer. With the advent of the new effective bonding materials many orthodontists prefer to use cuspid-to-cuspid/biscuspid-to-biscuspid bonded retainers to obtain optimal retention of lower anterior teeth both functionally and aesthetically. After experimenting with a variety of previous methods, such as the use of rubber bands, elastic threads, cotton pliers, ligature wires and silastic trays for the accurate placement and immobilization of a lower lingual retainer during the bonding, we have found that the use of two 1 to 1 1/2 inch pieces of 0.016 inch wires tack welded to lingual wire gives the best results. It is more accurate, simple, inexpensive and designed to save the orthodontist chair time.

Enamel demineralization and the length of intra-oral exposure to different concentrations of glucose or sucrose.

Six subjects wore intra-oral devices carrying eight bovine enamel blocks which were covered with a layer of S. mutans. They rinsed their mouths for five sec, one min, or multiples of one min with a 5 or 10% glucose (G) solution. Demineralization was measured after 45 min by determining the change in iodide permeability (delta Ip) of the enamel. In addition, saliva samples, taken at intervals during the test, were analyzed for G, and the time of clearance (tc) was calculated. Demineralization scores (delta Ip) were consistently greater from the 10% than from the 5% G solution. Both solutions produced an increase in delta Ip with an increase in the rinsing time (tr). The G remaining in saliva after the rinse did not significantly affect delta Ip. The delta Ip scores showed good correlation with the final pH of the S. mutants cell mass, r = -0.77. For each rinse solution, the scores also showed good correlations with tr (r = 0.87 and 0.79) and much weaker correlations with tr + tc (r = 0.44 and 0.53). Continuous in vitro exposure to 1, 5, or 10% solutions of sucrose (S) in saliva for 30 min or more caused a linear increase in delta Ip with time with no concentration effects. A linear increase was also observed in vivo when a one-minute mouth-rinse with 10% solution of S was administered every 30 min. The findings indicate that significant demineralization may occur while carbohydrate foods are consumed, and that brushing the teeth or rinsing the mouth after meals may not be as effective against caries as is generally believed.

Sugar clearance from saliva and intra-oral spaces.

The clearance of glucose from saliva was compared with that from spaces located in an intra-oral appliance. The spaces (N = 8) were similar in shape and size to posterior interdental spaces and could be sampled with a microsyringe without removing the appliance from the mouth. The subjects (N = 5) rinsed their mouths with solutions of 5, 10, or 25% glucose. Samples were obtained from a pair of spaces and from saliva at standard intervals and were analyzed for glucose. The rate of glucose clearance was consistently slower from the spaces than from bulk saliva, as shown by higher concentrations and longer clearance times for the spaces. The clearance curves were similar in shape and were rectilinear when the logarithms of the concentrations were plotted against time. The rate of clearance from the spaces appears to be characteristic for an individual, as was also true of salivary clearance.

Effect of some salts of calcium, sodium, potassium, and strontium on intra-oral enamel demineralization.

A newly-developed intra-oral enamel demineralization test was used to evaluate the effect of supplementation of a 10% sucrose solution with various components on enamel demineralization induced by the sucrose. Five human subjects wore a palatal prosthesis holding eight blocks of subsurface bovine enamel covered with a layer of S. mutans cells. The test involved rinsing with sucrose solution or with sucrose solution supplemented with 0.162 mol/l of different calcium salts or equivalent concentrations of Na-, K-, and Sr salts; rinsing was for one min at times zero and 45 min of the 90-minute test period. Ca-propionate, Ca-acetate, and Ca-levulinate completely inhibited sucrose-induced enamel demineralization; Ca-chloride, Ca-lactate, and Ca-ascorbate gave from 65-75%, and K-acetate, Na-lactate, and Sr-lactate 39, 25, and 18% inhibition, respectively. Consideration of the anion dissociation constants and the Ca-anion association constants of the salts suggests that the observed inhibition is caused mainly by common ion effects and, to a lesser extent, by buffer effects.

Enamel demineralization by mouthrinses containing different concentrations of sucrose.

Intra-oral enamel demineralization tests, involving rinsing with sucrose solutions (5, 1, 0.5, or 0.3%) at varying frequencies during a 1.5-hour period, showed that demineralization was a function of the total sugar dose (frequency of rinsing times concentration). Two rinses with a 5% solution caused demineralization, nine rinses were needed in the case of a 0.5% solution, and none occurred after nine rinses with a 0.3% solution. Remineralization was also observed and apparently occurred after exhaustion of the sucrose supply.

Enamel demineralization potential of dietary carbohydrates.

Mouthrinses with 5% solutions of different sugars were tested for their demineralizing effect on blocks of bovine enamel covered with a layer of S. mutans cells and carried in a palatal prosthesis. The extent of demineralization, as measured by the permeability of the enamel to iodide, was similar for fructose, glucose, and sucrose, less for maltose and lactose, and least for galactose.