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PubMed1989

Orthodontics. Provisional restorations and appliances.

Critical to optimal patient care is the proper sequencing of treatment for the integration of multidisciplinary procedures in solution of dental problems. Provisional restorations and appliances play a particularly critical role in management of adult mutilated or periodontally involved dentitions. They also play an important role for young patients with teeth lost through trauma or that are congenitally missing and require orthodontic therapy. Many restorative and periodontal problems cannot be corrected without orthodontic preparation of the dentition. Because orthodontic therapy is used to help create a therapeutic occlusion, this goal of therapy is important to describe.

Adolescent↗
PubMed1981

Orthodontic management of unilateral cleft lip and palate.

Experimental and clinical findings indicate that unfavorable adaptations of normal structures occur in children with clefts. It is postulated that these deviations from normal development are reversible and can be corrected or prevented by properly designed treatment. On this basis, five hypotheses were formulated and tested on the data from the subjects included in this study. The subjects consisted of 1) 16 children without clefts, 2) eight children who had complete unilateral clefts of the lip and palate but who had not received orthodontic treatment, and 3) 16 children who had complete unilateral clefts of the lip and palate and who had been treated by the described orthodontic procedures. The mean age for each group was 16 years. It was concluded that orthodontic treatment can be designed to : 1) counteract the forces which inhibit development of the maxillary alveolar process horizontally and vertically, 2) partially prevent the reduction in the forward growth of the maxilla, 3) provide adequate jaw and dental arch relationships, and 4) establish and maintain correct position of the maxillary segments.

Adolescent↗
PubMed1982

[Studies on new superelastic NiTi orthodontic wire. (Part 1) Tensile and bend test (author's transl)].

NiTi alloy has attracted the most public interest in recent years. This alloy has two unique properties, one is "shape memory effect" and the other is "outstanding elasticity". NiTi wire with the property of outstanding elasticity suggested it could be useful in orthodontics. Recently new NiTi alloy which had other characteristics of "superelasticity" was developed. In this study, new superelastic NiTi wire was examined to evaluate for use in orthodontics, in tensile and bend tests, compared with stainless steel, Co-Cr alloy and work hardened NiTi wire. The results obtained are as follows: (1) New superelastic NiTi wire showed unique stress-strain curve with a plateau from the strain of 2% to 5%, the unique deformation behavior was caused by stress induced transformation, and returned to almost zero strain as stress was reduced. (2) New superelastic NiTi wire showed an elongation of about 11%. In the cyclic tensile tests to the strain of 8%, new superelastic NiTi wire showed little permanent deformation of 0.5% after 10 cycles. (3) In bend tests, new superelastic NiTi wire showed lower than half load compared with stainless steel and Co-Cr alloy wires. Its permanent deformation was very little after 2 mm deflection. (4) The load-deflection curve of new superelastic NiTi wire showed almost constant load in the wide range of deflection. The results of this study indicate that new superelastic NiTi wire must be considered as a promising candidate for orthodontic arch wire.

Dental Alloys↗
PubMed1995

Orthodontic tooth movement and root resorption with special reference to force magnitude and duration. A clinical and histological investigation in adolescents.

The purpose of orthodontic treatment is to move teeth as efficiently as possible with least damage to teeth and their supporting tissues. Root resorption may occur as an unwanted side effect and may in some instances jeopardize an otherwise successful treatment. The general aim of this series of clinical investigations was to study the association between applied force, achieved tooth movement and related root resorptions. In 144 adolescents, the maxillary first or second premolar was buccally moved with a fixed orthodontic appliance. The variables studied were duration, magnitude and type of force. Moreover, both the occurrence of orthodontically induced root resorptions and the reparative potential were investigated in histological preparations of the teeth. When a continuous force of a clinically relevant magnitude (50 cN approximately 50 g) was applied, tooth movement increased gradually over time. Root resorptions were recorded in all test teeth but 4 (93%). After 3 weeks a few teeth revealed root resorptions extending half way to the pulp or more in the apical third of the root. No association was found between root resorptions and tooth movement. Doubling the force magnitude (100 cN approximately 100 g) affected neither the tooth movement nor the severity of root resorptions. However, when the force was increased 4 times (200 cN approximately 200 g), tooth movement increased 50% but still with no significant increase in the occurrence or severity of root resorptions. Tooth movement was achieved more efficiently with a continuous force than with an interrupted type of force of the same magnitude (50 cN). Root resorptions, though, did not seem to be affected differently by the two types of forces. Reduction of all types of applied forces was considerable, about 25-30%, already within one week. Repair with secondary cementum was recorded almost 3 times more often after 8 weeks (75%) of retention than after 1 week (28%). Irrespective of magnitude and type of force, large individual variations were observed regarding tooth movements and root resorptions as well as their reparative potential. The possible clinical consequences of the results obtained are discussed with regard to cost-benefit effects, convenience to the patient and risk of complications.

Adolescent↗
PubMed1995

Occlusal principles in orthodontics.

Morphologic and functional requirements of the orthodontically treated occlusion are discussed in this article. In the past, orthodontic treatment has been viewed as both a cause and a cure for temporomandibular disorders. This article reviews the literature, orthodontic implications of occlusal appliance therapy, and case reports.

Adult↗
PubMedDate not supplied

The orthodontic-periodontal connection in implant site development.

Implant-supported restorations have become an established treatment modality, well accepted by patients and clinicians. Regaining function is now routinely expected, and the focus of patient demand has shifted to aesthetics. Aesthetic restoration of the partially edentulous anterior maxilla can be particularly challenging. The learning objective of this article is to present a comprehensive multidisciplinary treatment protocol, developed to establish a foundation for optimal aesthetics in implant therapy, with emphasis on the role of orthodontics in the enhancement of deficient components. Periodontal orthodontics is used to increase the vertical osseous dimension and preserve papillae; restorative orthodontics optimizes the site through manipulation of supragingival restorative space. Two clinical cases are utilized to illustrate the principles and implementation of this protocol.

Adult↗
PubMed1995

A radiographic comparison of apical root resorption after orthodontic treatment with the edgewise and Speed appliances.

Apical root resorption is a serious iatrogenic problem sometimes associated with orthodontic treatment. The Speed appliance (Strite Industries, Ltd., Ontario, Canada) provides a continuous rotatory and torque action through its spring clip mechanism, in contrast with the edgewise appliance that may provide an interrupted force. The effect of continuous action on root resorption compared with the interrupted action of the edgewise system has not been investigated previously. The purpose of the present investigation is to test the null hypothesis that there is no difference in the apical root resorption seen after orthodontic treatment with the edgewise straight wire and the Speed appliance systems. Pretreatment and posttreatment periapical radiographs of 63 patients, (30 treated with the Speed 0.018 bracket and 33 with the 0.018 edgewise bracket) were studied. The long cone paralleling technique was used for all the radiographs. Any image distortion between the pretreatment and posttreatment radiograph was calculated and compensated for by using the crown length measurements, on the assumption that the crown length remains unaltered during the treatment period. Quantitative measurements of crown and root lengths for the maxillary and the mandibular central and lateral incisors were compared. Means and standard deviations for the percentage root resorption per tooth group were calculated. A three-factor analysis for variance (ANOVA test) was performed to determine whether there was an appliance, treatment, or gender effect on the amount of root resorption seen after treatment. No statistically significant difference in root resorption between the two appliance systems was found.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1999

Treatment results in dental school orthodontic patients in 1983 and 1993.

The effect of incremental changes in materials and techniques on orthodontic treatment outcomes is difficult to evaluate objectively. Treatment results for two groups of patients whose treatments were completed approximately 10 years apart were evaluated using the peer assessment rating (PAR) index and the index of orthodontic treatment need (IOTN) using the Wilcoxon matched-pairs signed-rank test. Patients in the later group who had been treated by postgraduate students primarily (using fixed appliances) had significantly lower IOTN and PAR scores at the end of treatment and showed a significantly greater reduction in the PAR score than a similar group of patients in the earlier group. There were no significant differences in treatment results between patients in the early and late groups who were treated with removable appliances. Differences in treatment results were most likely the result of changes in materials and techniques that had occurred in the 10 intervening years.

Adolescent↗
PubMed1998

Effect of orthodontic appliance reactivation during the period of peak expansion in the osteoclast population.

BACKGROUND: Delays in the appearance ofosteoclasts at compression sites occur following orthodontic appliance reactivation when this is done during the period of osteoclast recruitment. This study examined changes in alveolar bone after appliance reactivation at a time coinciding with the peak expansion of the osteoclast population following the first appliance activation. METHODS: Orthodontic appliances were activated with 40 g on maxillary molars followed by a reactivation with the same force after 4 days in one group and sham reactivation in the other. Rats were killed at 0, 1, 3, 6, and 10 days thereafter. Orthodontic movement was measured cephalometrically. TRAP and interleukin-1 alpha (IL-1alpha) were measured biochemically, and changes in osteoclasts and root resorption were assessed at both compression and tension sites histomorphometrically. RESULTS: Teeth in the reactivated group displayed more initial displacement than controls but no more tooth movement 10 days following appliance reactivation. Also, increases in osteoclast numbers and surface percent, as well as alveolar bone Tartrate-resistant acid phosphatase (TRAP), became evident in the treated animals only 10 days after reactivation. However, IL-1alpha was elevated in alveolar bone within 1 hr following appliance reactivation but returned to baseline by day 1. There were no treatment-related difference in nuclear number per osteoclast or trabecular surface per osteoclast. Significant treatment-related increases in root resorption were evident at compression sites by day 10. CONCLUSIONS: These findings indicate that after appliance reactivation during the height of osteoclastic stimulation, a second cohort of osteoclasts can be recruited, but only after a delay of several days. This delay is not due to a failure to produce IL-1alpha in the tissues.

Acid Phosphatase↗
PubMed1999

Effect of copper addition on the superelastic behavior of Ni-Ti shape memory alloys for orthodontic applications.

Transformation temperatures and mechanical properties such as transformation stresses at different temperatures, superelasticity characteristics, and load cycling behavior have been investigated in NiTiCu orthodontic archwires with various copper concentrations. The results have been compared with the conventional NiTi orthodontic archwires. The addition of copper was effective in narrowing the stress hysteresis and in stabilizing the superelasticity characteristics against cyclic deformation, with the result that the slope of the load-deflection unloading curve of the alloy is lower than NiTi. Moreover, it produced greater stability of both the transformation temperature and the force applied to the teeth for a determined design and wire cross-section. On the other hand, the presence of copper in NiTi orthodontic archwires reduced the ageing effect. Studies of ion release in artificial saliva showed only small quantities after long periods of immersion.

Copper↗
PubMed2002

The anticorrosion ability of titanium nitride (TiN) plating on an orthodontic metal bracket and its biocompatibility.

Typically, an orthodontic metal bracket is made from stainless steel. It has been shown that such metal may corrode in an acid- and chloride-rich environment. The purpose of the current study was to investigate a titanium nitride (TiN) ion-plated stainless steel orthodontic bracket's anticorrosion properties and compare its biocompatibility with that of non-TiN-plated brackets. The stainless-steel brackets studied here were tested in acidic artificial saliva. The plated metal bracket was produced by the titanium nitride (TiN) ion-plating method. The TiN-plating on the bracket surface was demonstrated to be successful by EDX analysis. The quantity of metallic-ion release under test immersion solutions was analyzed by atomic absorption spectrophotometry. Both TiN- and non-TiN-plated brackets may release detectable ions into the test solution, including nickel, chromium, manganese, copper, and iron (ferric). The anticorrosion ability of the plated bracket was analyzed by means of inductively coupled plasma atomic emission spectroscopy. The results revealed that the TiN-plated metal bracket did not increase the anticorrosion ability of the standard bracket. The biocompatibility of the TiN plating versus the standard bracket material resulting from bracket immersion in the test solution revealed no toxicity on U2OS cells using a methylthiazole tetrazolium (MTT) colorimetric assay. Clearly, the search for an improved technique for enhancing the anticorrosion ability of the normal metal orthodontic bracket should be continued.

Cell Line↗
PubMed2004

Properties of super stainless steels for orthodontic applications.

Orthodontic stainless-steel appliances are considered to be corrosion resistant, but localized corrosion can occur in the oral cavity. This study was undertaken to evaluate the properties of super stainless steels in orthodontic applications. Accordingly, the metallurgical properties, mechanical properties, corrosion resistance, amount of the released nickel, cytotoxicity, and characteristics of the passive film were investigated. Corrosion resistances of the specimens were high and in the following order: super austenitic stainless steel (SR-50A) > super ferritic stainless steel (SFSS) = super duplex stainless steel (SR-6DX) > 316L SS > super martensitic stainless steel (SR-3Mo) in artificial saliva, 37 degrees C. At 500 mV (SCE), current densities of SR-50A, SFSS, SR-6DX, 316L SS, and SR-3Mo were 5.96 microA/cm(2), 20.3 microA/cm(2), 31.9 microA/cm(2), 805 microA/cm(2), and 5.36 mA/cm(2), respectively. Open circuit potentials of SR-50A, 316L SS, SR-6DX, SR-3Mo, and SFSS were - 0.2, - 0.22, - 0.24, - 0.43, and - 0.46 V (SCE), respectively. SR-50A, SFSS, and SR-6DX released below 3 ng/ml nickel for 8 weeks, and increased a little with immersion time, and 316L SS released about 3.5 ng/ml nickel, but SR-3Mo released a large amount of nickel, which increased with immersion time. The study demonstrated that SR-50A, SR-6DX, and SFSS have high corrosion resistance and mild or no cytotoxicity, due to the passive film enhanced by synergistic effect of Mo + N or by high addition effect of Cr + W. All super stainless steels showed very low cytotoxicity regardless of their nickel contents, although SR-3Mo was found to be relatively cytotoxic. From these studies, these steels are considered suitable for orthodontic applications.

Biocompatible Materials↗
PubMed1992

Laser etching of teeth for orthodontic bracket placement: a preliminary clinical study.

Current interest in the use of layers in clinical dentistry has suggested that this technique may be applicable to enamel etching in orthodontics. A pulsed Nd:YAG laser was used to etch the enamel surfaces of teeth in vivo prior to the bonding of orthodontic brackets with composite resin. Overall laser bonding took considerably longer, was less reliable in terms of bond strength, and produced more discomfort than conventional acid etching. The use of the ND:YAG laser for etching teeth prior to bonding orthodontic brackets is not recommended.

Acid Etching, Dental↗
PubMed2000

Efficacy of protection by latex gloves during orthodontic therapy.

The wearing of gloves during orthodontic or dental treatment is generally indicated for reasons of hygiene and protection against infection. This study was aimed at determining the extent and localization of perforations caused by the various orthodontic treatment techniques and interrupting the infection barrier. The impermeability was tested by means of a water retention test according to European standard EN 455, Part 1, performed on 1600 Centramed (Centramed, Koblenz), Tekmedic and SafeEx non-sterile disposable latex gloves (both by Safe Med, Switzerland) and Safe Gan latex gloves with an additional acrylate coating (also by Safe Med). The perforation rate in unused gloves was between 0.5% and 7.5%, rising on average to 11% with increasing use. 36% of the total number of lesions resulted from handling removable appliances, and 57% from handling fixed appliances, especially when replacing arch wires and elastics. Most lesions were in the thumb, index finger and palm region. Only 18% of the defects were noticed by the dentists themselves. The gloves worn by beginners in their first year of postgraduate orthodontic training had about twice as many defects as those worn by qualified orthodontists. When patients with an increased risk of infection are to be treated, additional hand disinfection measures should be taken and 2 pairs of gloves worn in view of the relatively unreliable protection offered by commercially available latex gloves.

Chi-Square Distribution↗
PubMed1998

In vitro investigation into the biological assessment of orthodontic wires.

The alloys used in orthodontics are subject in the moist environment of the oral cavity to various corrosion processes. If the products of the corrosion are introduced into a biological system they may cause changes. In the present investigation the corrosion rate of 23 different orthodontic wires (preformed arch wires and straight wires) made from 5 different alloys were examined in a nutrient medium by ICP-AES analysis, and the influence of the corrosion products on the cytotoxicity of a fibroblast culture was investigated using Mosmann's MTT test. The nickel-titanium wires Nitinol, Sentalloy and Original Chinese Wire and the beta-titanium alloy TMA had no effect on the rate of cell proliferation. Nor did stainless steel wires inhibit growth significantly, with the exception of Australian Wire and Wildcat Wire. The manganese-steel alloys Noninium h and Mezanium caused significant reductions in growth rate, which were attributed to the manganese ions released by the corrosion. The most severe growth inhibition was caused by the Co-Cr-Ni alloy Elgiloy, and this reaction is independent of the 4 levels of resilience. The degree of growth inhibition depended upon the concentration of corrosive cobalt and nickel ions in the eluate. In spite of the differences observed, all the orthodontic wires examined are graded under ISO-standard 10993-5 as "non-cytotoxic". The degree of toxicity was found to be determined essentially by the corrosion rate of the alloy and the cytotoxic characteristics of the resulting trace elements.

Animals↗
PubMed1998

Cariostatic effect of a light-cured, resin-reinforced glass-ionomer for bonding orthodontic brackets in vivo. A combined study using microradiography and confocal laser scanning microscopy.

The aim of this study was to evaluate in vivo the cariostatic potential of the resin-reinforced glass-ionomer (Vitremer core build-up restorative; 3M Dental Product Division) when used as a bonding agent for orthodontic brackets. The mineral distribution and topography of the enamel surface adjacent to the bracket base was determined by quantitative microradiography (TMR) and confocal laser scanning microscopy (CLSM). The study was designed in split-mouth technique using 9 pairs of premolars to be extracted for orthodontic reasons. One tooth of each pair was bonded with the resin-reinforced glass-ionomer, and the control contralateral premolar with the non-fluoridated composite (Concise, 3M Dental Products Division). After 4 weeks all teeth were extracted and stored until analysis. The lesion depths and mineral loss values in enamel adjacent to brackets bonded with Vitremer were significantly lower than in teeth bonded with the composite, indicating that the resin-reinforced glass-ionomers significantly reduced caries lesion development in vivo. CLSM images show a severe cariogenic challenge around orthodontic brackets and support TMR measurements.

Bicuspid↗
PubMed1999

Orthodontics at the turn of the century. A discussion of some relevant aspects.

Some changing paradigms, that might influence orthodontics in the future, are being discussed: economic problems related to our welfare systems; development of the media societies; concepts of normality; future changes as regards the type of treatment records; evaluation of treatment outcome; "exaggerated orthodontics?"; orthodontics and facial aesthetics; Newtonian paradigms and scientific revolution; the growth of knowledge; phenomenology; tacit knowledge; decision making.

Esthetics, Dental↗
PubMed1990

[The treatment of adults with removable appliances? A contribution to orthodontic-prosthetic collaboration].

Request of adults for orthodontic treatment increases. In that cases requirements to the practitioner are of many kinds, especially if in consequence of secondary changes after lost of teeth the patient is not able, as in the past to accept his irregularities of teeth in relation to masticatory, physiognomic and phonetic function. Absolutely there is willingness to wear also removable orthodontic appliances. Possibilities and advantages of plates for orthodontic-prosthetic problems are discussed and examples of treatment demonstrated.

Adult↗