Appliance Wear Research Articles

Micro-electronic monitoring of functional appliance wear

Measurement of actual bionator wear has so far been confined to a few studies involving only small samples. In this study a micro-electronic timing device was used in a greater number of patients (53 children) after the system proved to be reliable in a pretest involving 18 subjects. The patients were 9-14 years of age and had a timing device fitted in their bionators over a period of 3-6 months. The data were read from the memory chip at the regular treatment sessions every 3-4 weeks. There was evidence that the patients averaged 7.65 hours per day of wear, thus fulfilling only 50-60 per cent of the orthodontist's requirements. Further details and implications of the measurements are discussed.

Accumulation of Enamel Constituents in Streptococcus mutans Plaque during Intraoral Demineralization

Studies were carried out with an intraoral demineralizing system in order to determine whether calcium and inorganic phosphate (Pi) accumulate in plaque during active demineralization of enamel. Blocks of bovine enamel were coated with Streptococcus mutans and were carried in palatal appliances worn by human volunteers. Demineralization was determined as changes in the iodide penetrability (delta Ip) of the enamel surfaces. Ca and Pi were determined in the extracellular spaces of the synthetic plaque. Delta Ip increased with time after administration of rinses containing 5% (w/v) sucrose, while plaque pH dropped and then returned toward neutrality. Ca increased to 10.9 +/- 2.8 mmol/l at 30 min, while Ca2+ and Pi rose to 3.0 +/- 2.1 and 9.5 +/- 3.1 mmol/l, respectively. The Ca:Pi ratio was 1.15. Rinses with 10% (w/v) sucrose gave similar results. Concentrations of Ca and Pi were considerably higher than those in saliva. Accumulation of the mineral constituents was shown to be dependent on metabolic activity of the S. mutans plaque, and experiments in which enamel blocks were replaced with blocks made of acrylic plastic gave Ca and Pi concentrations of 2.5 +/- 0.6 and 6.6 +/- 2.4 mmol/l, respectively, demonstrating that most of the Ca and about one-third of the Pi were derived from enamel. The data suggested, furthermore, that Ca and Pi were partially bound to complex macromolecules, and that part eventually recrystallized as mineral within the plaque.

Internal derangement of the TMJ: Changes associated with mandibular repositioning and orthodontic therapy

Because of its apparent success in relieving symptoms, especially pain, anterior mandibular repositioning therapy is a popular mode of nonsurgical treatment for patients with painful, clicking internal derangement of the tempo romandibular joint. Posterior open bites are a frequent consequence of such therapy and may necessitate either continued appliance wear or closure by equilibration, prosthetics, or orthodontics. The anatomic and functional changes that occur subsequent to mandibular repositioning during orthodontic closure of the posterior open bite are not well understood. A case of a patient with a Class II, deep bite malocclusion and painful internal derangement of the TMJ is presented. Transcranial and cephalometric radiographs, arthrograms, and mandibular movement recordings were obtained before treatment and after both repositioning therapy and orthodontic treatment. Regarding occlusal improvement and pain relief, the treatment was successful. However, not all of the changes that occurred during repositioning therapy were maintained after orthodontic treatment. The strategy used in this case (mandibular repositioning /orthodontic finishing) was evaluated by an examination of these anatomic and functional changes with a discussion centered on the possible mechanisms involved.

Collagenolytic and phosphatase activity in the rat mandible after functional protrusion

The effect of chronic mandibular protrusion on the collagenolytic and phosphatase activity of several mandibular bone sites and the condylar cartilage was evaluated. Ninety-three male Sprague-Dawley rats were equally divided into two experimental and one control group. One experimental group wore a protrusive appliance for 2 weeks, the other for 4 weeks. All animals were killed at 59 days of age. Collagenolytic, alkaline and acid phosphatase activities were determined in the condylar cartilage, the subchondral bone and condylar neck, and in the gonial angle and coronoid process. In the cartilage and subchondral bone, the protrusive appliance caused a reduction in collagenolytic and alkaline phosphatase activity. In the condylar neck, it caused a large increase in collagenolytic activity and a decrease in alkaline phosphatase activity in both experimental groups. In the gonial angle and coronoid process, the appliance increased the collagenolytic activity only in the 2-week group. In the 4-week group, the alkaline phosphatase and collagenolytic activities were not different from the activities in those tissues in the control animals. Thus a protrusive appliance induced quantitative changes in enzyme activities in condylar cartilage and mandibular bone. The increase in collagenolytic activity (representing increased bone resorption) occurred typically in areas of muscle attachment and might have been the result of the neuromuscular changes induced by the protrusive appliance. The recovery to normal values of collagenolytic activity in the coronoid process and gonial angle of the 4-week group suggests that at these sites the muscles (and subperiosteal bone) might have adapted to their new biomechanical environment after the longer period of appliance wear.

A removable appliance for alignment of second molars

On occasion active orthodontic treatment may be terminated before complete eruption of the second molars. A standard Hawley removable appliance used for retention after active orthodontic treatment can be modified to improve alignment of buccally positioned second molars (Fig. 1). Fig. 2 demonstrates the results of full-time appliance wear for a 3-month period. The appliance is fabricated by adding a 0.030-inch spring to a standard Hawley removable appliance. The spring may be soldered to an Adams clasp on the first molar. Two horizontal helices are incorporated into the spring to ensure that a desirable force and rate are obtained. Acrylic must be relieved from the lingual surface of the teeth to be moved. If mesiopalatal rotation is also desired, a recurve extension can be incorporated into the spring (Fig. 3).

STOMA APPLIANCE WEAR

STOMA APPLIANCE WEAR

A model for the production of artificial caries in the mouth in man

Sixteen blocks of enamel were sliced from the buccal surfaces of caries-free human premolars and mounted in an appliance worn in the mouth by one individual for 6 months. Eight of the blocks were arranged in pairs with buccal surfaces in contact. The other eight were not in contact but were able to accumulate plaque by being recessed in the appliance. Lesions formed in all specimens, the depths of which were measured in ground sections; around contact surfaces, these formed at only half the rate of those not in contact. Histologically, lesions on contact surfaces were similar to natural lesions, but the shape of the artificially-induced lesions was greatly influenced by the curvature of the buccal enamel.

Patient cooperation in treatment with removable appliances: A model of patient noncompliance with treatment implications

The uncooperative or noncompliant patient presents a substantial problem during treatment with removable orthopedic/orthodontic appliances. Frequently, the uncooperative patient is labeled as having a poor or defiant attitude toward orthodontic treatment. In contrast to this attitude model of patient noncompliance, this article presents an analysis of uncooperative behavior in terms of behavior-environment relationships. The authors bring together backgrounds of expertise in both clinical psychology and orthodontics. The behavioral model presented is applied to clinical orthodontic patients undergoing treatment with removable functional appliances. Preliminary research findings suggest that the behavioral model described is a successful system for the introduction of a removable device to be worn by the patient. The techniques described also are useful for the previously uncooperative patient undergoing remedial treatment. Another major benefit of using this strategy is found in the response of the children's parents. The approach reduces the potential for and frequency of parent-child conflicts over dental health. Currently, a small sample of children are being treated by the behavioral method. Both parents and patients are involved. A specific schedule for wearing of a removable appliance is identified, along with parental observations and rewards based on patient compliance. Once the youngster is regularly meeting criteria, the program is altered to increase the desired response of appliance wear. The behavioral model has implications for various aspects of orthodontic care, including the use of such appliances as the Fränkel, Bionator, headgear, intraoral elastics, and proper lip posture. On the basis of this functional analysis of behavior, implications for treatment and prevention of noncompliance in orthodontic patients are discussed.

Intensive treatment of severe Class II malocclusions with a headgear-Herbst appliance in the early mixed dentition

In the correction of large sagittal discrepancies in the relationship between the maxilla and the mandible, the orthopedic effect of treatment is often of small magnitude when compared with the dentoalveolar changes. A group of patients with severe Class II malocclusions were treated to assess the effects of a therapeutic approach which specifically took into consideration important factors such as type of anchorage, amount of force, age at start of treatment, and intensity of treatment to obtain the maximal orthopedic improvement. A special headgear-Herbst appliance was designed and short intensive treatment, lasting 5 months, was performed in the very early mixed dentition. Comparison with an untreated control group revealed the dramatic effects of treatment. The overall average change in the sagittal relationship between the maxillary and mandibular teeth was 7.5 mm after active treatment. The posteriorly directed effect on the maxilla of 3.1 mm was due to a combination of distal movement of the dentoalveolar arch and of posterior translation of the basal portion of the maxilla. The anteriorly directed effect upon the mandible of 4.4 mm was due mostly to anterior movement of the basal part of that bone, with a small part resulting from labial movement of the lower incisors. This appeared to be the result of a stimulation of growth of the mandibular condyles, a change in mandibular morphology, and an anteroinferior change in position of the condyles with a possible anterior translation of the glenoid fossa. After a 10-month posttreatment period during which an activator was used during the initial 6 months, a new comparison between the treated group and the control group was made. Growth continued to the same extent in the treated group as in the control group. However, a tendency toward relapse in overjet of 2.3 mm was observed, leading to some modifications in the treatment approach in recently started cases. A short period of interceptive orthopedic treatment in the very early mixed dentition may be indicated to correct skeletal deviations and establish a normal relationship between the maxilla and the mandible. Treatment could then be followed by a period without appliance wear until final dentoalveolar adjustments, if necessary, are made in the permanent dentition.

Speech Changes Following Orthodontic Treatment With The Functional Regulator

SummaryCleft palate children exhibiting maxillary segment collapse underwent orthodontic treatment with the Functional Regulator (FR). Audio and video recordings of speech were obtained periodically in conjunction with appliance management. Judges evaluated the recordings obtained with and without the FR in place by assessing speech intelligibility, resonance and nasal emission. Results indicated: a) changes in maxillary width and cross‐bite relationships were not clinically significant; b) articulation, hypernasality and nasal emission were judged to be significantly more severe during appliance wear; c) video taped speech samples were judged to be significantly less intelligible than audio taped samples; d) a substantial amount of accommodation to the FR occurred at one‐two weeks post insertion, but maximum improvement in speech intelligibility occurred over the period evaluated; and e) good speech production skills prior to orthodontic treatment minimised the adverse effect of the FR on speech intelligibility.

The MARS appliance: Report of a case

Inconsistent wearing of functional appliances, intermaxillary Class II elastics, and headgear during the treatment of Class II malocclusions is a common concern of many orthodontists. The MARS ( Mandibular Advancing Repositioning Splint) is a functional device designed to overcome many such cooperation deficiencies. The MARS appliance is a fixed functional device which is attached to the arch wires of a multibanded orthodontic appliance. It is composed of a piston and cylinder which attach to the lower canine and the upper molar region of the dental arch wires on each side of the jaw. It forces the patient to maintain the mandible in a protruded position 24 hours a day and yet allows full and complete opening and closing as well as lateral excursive movement. The design, method of attaching, and adjustment of the appliance during treatment are discussed, and the results achieved in a single case are described. The results being achieved in the pilot study so far are encouraging and are being pursued further.

A Preliminary Report into the Development and use of Soluble Controlled-release Glass Timing Discs Implanted into Orthodontic Appliances

An investigation is reported into the development and use of soluble controlled-release glass timing discs as a possible method of assessing patient co-operation in the wearing of removable orthodontic appliances.

Functional regulator therapy for cleft palate patients

Nine cleft lip and palate children exhibitng collapse of maxillary segments and cross-bite were treated orthodontically with the functional regulator (FR) for periods ranging from 6 to 18 months. The purpose of this investigation was to evaluate quantitatively treatment of cleft palate patients with the functional regulator and to evaluate the effect of the appliance on their speech. Cleft palate patients typically have speech, nose, and lip defects which make patient cooperation and appliance acceptance more difficult. However, patient cooperation was considered good with an average mean of 12.7 hours per day of appliance wear and a range of 5.6 to 18.2 hours. Change in interimplant dimension was measured on frontal radiographs, and dental changes were measured of serial dental casts. The resulting data indicated no significant change in maxillary width or cross-bite relationship. The functional regulator was not clinically useful in this sample when the treatment objective was primary expansion of collapsed maxillary segments in the cleft palate patient. Good speech-production skills prior to treatment will minimize the adverse effect that the FR has on speech intelligibility. A significant amount of accommodation to the appliance occurs within 1 week after insertion, but maximum improvement in speech intelligibility occurs with full-time wear of the appliance for as many hours per day as possible.

The effects of maxillary expansion using a quad-helix appliance during the deciduous and mixed dentitions

Ten subjects, five in the deciduous dentition and five in the mixed dentition (x̄ age = 6 years 9 months), had functional posterior cross-bites successfully corrected with fixed lingual arch wire expansion appliances of the quad-helix design. The appliance, in the context of “early” treatment, produced midpalatal suture separation on each subject as evidenced on occlusal radiographs. While the relative orthopedic and orthodontic changes were not determined, the maxillary intermolar and intercanine transverse measurements showed significant increases in all subjects, with mean values of +5.3 mm. and +4.1 mm., respectively. The active phase of treatment averaged 30 days and 1.1 adjustments for the desired expansion to be achieved. Incorporating a standard 6-week retention period, the total appliance wear time had a mean value of 75 days. Following a 3-month postretention adjustment period, relapse of the intermolar and intercanine transverse dimensions presented mean decreases of −1.5 mm. and −1.9 mm., respectively. The relapse potential was successfully compensated for by overexpansion of 2 to 3 mm. during the active phase of treatment. No significant differences were demonstrated between the deciduous- and mixed-dentition groups during the course of maxillary expansion with the quad-helix appliance.

Orthosurgical teamwork

A series of orthognathic cases illustrates the potential service that is available to young adult and adult patients. These patients have problems that are not within the therapeutic possibilities of orthodontics alone. From a variety of viewpoints--length of time, appliance wear, iatrogenic damage, and patient concern--such procedures may well be preferred and ultimately more successful and stable than alternate conventional orthodontic therapy. Surgical procedures, in combination with orthodontics and prosthetics, have now achieved a level of sophistication that permits correction of almost any type of facial deformity quickly, with minimum pain, and relatively few unfavorable sequelae.12.13.15.

A roentgenographic appraisal of maxillary anterior lingual root torque in the third stage of the begg technique

cipitate a favorable behavioral response with this method. Thirty-one patients were included in this study, from eleven to twenty-one years of age with the mean age seventeen years, while the mode was fifteen years. Areas studied were oral hygiene care, band and arch wire care, extraoral appliance and elastic wear, fitting of orthodontic bands on apprehensive or hypersensitive patients, and transfer of motivational control to the referring orthodontist. Pernicious habits treated included tongue-thrust, thumb-sucking, and nail-biting. Various induction procedures were utilized, and three to four sessions were given, which averaged a total of approximately 3 hours for conditioning the patients. Results were checked after 1 month and 2 months and were found to be successful in all areas of the study. There was a 94 per cent success rate after 1 month and a 79 per cent success rate after 2 months. Waking-state suggestion was successful in one case attempted in which a formal induction method was not utilized. Psychosomatic motivation therapy can be effectively administered to the uncooperative orthodontic patient or to patients with pernicious habits. Time to condition the patient may be a disadvantage, but it must be compared to time lost in treating the uncooperative patient. Patients could possibly be referred to a qualified therapist for conditioning and then be referred back to the orthodontist for orthodontic treatment.

Counsel to the aging dental patient

It is important for the modern dentist to be able to control dental and periodontal diseases so that their ravages will not cause such a loss of esthetics or efficiency which might invite emotional upheaval and make living miserable, even if the life span is increased. Complete dentures are to be delayed as long as possible by proper dental care. The extraction of the teeth and rapid conversion to complete dentures are to be avoided when possible because of the psychologic impact. When such a step must be taken, careful psychic readjusment should be brought about with careful consultation with the dentist. With such adjustment, happiness in the wearing of artificial dental appliances is possible.

Chlorophyll stain penetration of a tooth: Report of a case

A case of green-black staining of an upper central incisor tooth apparently caused by the slight penetration of chlorophyll through clinically intact enamel is reported in a patient treated for chronic gingivitis coincident with the wearing of orthodontic appliances.

Time to begin orthodontic treatment

Some authors believe that when anterior spacing fails to occur in the primary arches, mechanical stimulation should be applied to expand them and allow room for the eruption of the permanent incisor teeth without crowding. Others condemn this practice on the basis that lateral growth concurrent with the eruption of the permanent incisors will accommodate them in excellent positions. Most authors agree that treatment in the primary dentition should be limited to those conditions which prevent the continued development of normal occlusion and obviously will not correct themselves. Among those conditions which indicate treatment during this stage are extreme distoclusions, almost all mesioclusions, and posterior and anterior cross-bites. Concerning treatment in the mixed dentition, opinion varies greatly. Some consider this the most advantageous time for treatment; others feel that there are almost no indications for treatment during this stage. The general concensus of opinion seems to indicate that only mesioclusions. extreme distoclusions, and cross-bites (anterior or posterior) should be treated during this stage. In some cases, the primary canines may be extracted to relieve crowding of the permanent incisors. Following this procedure, a preventive lingual arch wire should be placed. Occipital anchorage may be utilized to advantage in treating Class II, Division 1 cases in the mixed dentition. With those exceptions previously mentioned, the period immediately following the eruption of the permanent second molars is the period during which most orthodontic treatment should be initiated. At this time the full volume of tooth substance is present, the individual growth pattern is well established, there are sufficient teeth to receive nearly any type of appliance, and the patient can easily tolerate the wearing of appliances.