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PubMed1982

Tissue tolerance to orthodontic banding. A study in carbohydrate metabolism.

Tissue tolerance to orthodontic banding was determined in a group of children in the Department of Orthodontics at the University of Alabama School of Dentistry. Nonfasting blood glucose and three oral parameters--gingival state, clinical tooth mobility and labial debris--were determined before banding a mandibular lateral incisor and again one month later. Each subject received a multivitamin-trace mineral supplement or an indistinguishable placebo during that month. In the placebo group, statistically significant blood glucose variability (variance) was found in those whose periodontal state was made worse by the orthodontic band. However, a very homeostatic pattern of blood glucose values was displayed by those whose gingival state, tooth mobility, and labial debris improved or remained the same in the presence of the band. Thus, blood glucose variability or homeostasis is one possible way to predict or measure the elusive factor that has been called tissue tolerance.

Blood Glucose↗

PubMed1991

Evaluation of orthodontic results--a discussion of some methodological aspects.

The informative value of clinical material presented at meetings and in the literature poses a dilemma for the typical orthodontist. To aid in the resolution of this problem, methodological aspects of the following topics are discussed: criteria for the evaluation of orthodontic treatment results, the selection of cases to be evaluated, the presentation of orthodontic treatment results and the interpretation of case presentations. Orthodontic relapse should be considered to be a number of continuous variables affecting treatment results; different follow-up criteria should be employed when comparing pretreatment, posttreatment and postretention results.

Evaluation Studies as Topic↗

PubMed1996

The effect of sandblasting on the retention of orthodontic bands.

A variety of luting cements are available for use with orthodontic bands. This in vitro study was conducted to evaluate the force required to cause debanding when zinc phosphate, polycarboxylate and glass ionomer cements are used as the luting agents; and to determine whether sandblasting the inner surface of orthodontic bands affects the force required to deband. The data were obtained by debanding cemented stainless steel bands from 20 extracted third molars. Glass ionomer cement demonstrated the highest mean force value required to deband both the nonsandblasted and sandblasted orthodontic bands. Sandblasting the inner surface of the bands proved to be a significant (P < 0.001) method for increasing band retention for all three cements tested. The mean force required to deband using zinc phosphate, polycarboxylate and glass ionomer cements was approximately doubled following sandblasting.

Dental Bonding↗

PubMed1996

A three-year clinical trial using a glass ionomer cement for the bonding of orthodontic brackets.

Recent clinical studies measuring orthodontic bracket failure, when using glass ionomer cement as an adhesive, have reported a wide range of percentages of bracket failure. The present study recorded bracket failure over a 3-year period, longer than had been previously measured. Seventeen participants were randomly assigned to one of two treatment groups, either using glass ionomer cement or composite resin for bonding. In each group, brackets were bonded to incisors, canines, and premolars. Bracket failure was measured over the duration of comprehensive orthodontic treatment for all participants. Brackets bonded with the glass ionomer cement were more likely to fail (log-rank test; P < or = 0.022). This difference was clinically significant. At the present time, the disadvantage of extra bracket failures appears to outweigh potential advantages when considering glass ionomer cement for the routine bonding of orthodontic brackets.

Adhesives↗

PubMed1996

Effect of applying chlorhexidine antibacterial agent on the shear bond strength of orthodontic brackets.

The purpose of this study was to determine whether the application of chlorhexidine as an antibacterial agent affects the shear bond strength and debonding failure modes of orthodontic brackets. Thirty-six recently extracted human premolars were cleaned and randomly assigned to one of three groups: prophylaxis with pumice only prophylaxis using a 13,500 ppm fluoridated pumice, and prophylaxis with pumice followed by application of 0.12% chlorhexidine paste. All teeth were etched with a 37% phosphoric acid gel and metal orthodontic brackets were bonded to each tooth using the same bonding system. The teeth were mounted in phenolic rings and stored in deionized water at 37 degrees C for 72 hours. A Zwick Universal Testing Machine was used to determine shear bond strengths. The residual adhesive on the enamel surfaces was estimated using the Adhesive Remnant Index. The analysis of variance was used to compare the various groups. Significance was predetermined at P < 0.05. The results indicated that there were no significant differences in bond strengths between the chlorhexidine-, fluoride-, and nonfluoride-treated teeth (P = 0.233). The Chi-Square test evaluating the residual adhesive on the enamel surfaces also showed no significant differences (P = 0.456) between the various groups. In conclusion, the use of chlorhexidine and/or fluoride prophylactic pastes does not significantly affect shear bond strength nor bond failure location of orthodontic brackets.

Acid Etching, Dental↗

PubMed1996

The effect of acetaminophen, ibuprofen, and misoprostol on prostaglandin E2 synthesis and the degree and rate of orthodontic tooth movement.

The present study compared the effect of acetaminophen, ibuprofen and misoprostol on PGE2 synthesis and orthodontic tooth movement. Guinea pigs were randomly assigned into one of three test groups or a control group. Each group received study treatments every 12 hours as an orthodontic force was applied to the maxillary incisors. Direct linear measurements of tooth separation were recorded at days 2, 4, 6, 10, and 11, and inflammatory exudate from the periodontal ligament (PDL) space was extracted and quantitatively analyzed radioimmunologically for the presence of PGE2 at days 4 and 9. Comparing the concentration of PGE2 in sample extracts, a significant difference (P = 0.001) was found among drug groups. A highly significant difference was found between the mean tooth separation among the various drug groups (P < 0.001). At day 11 the misoprostol group exhibited 4.49 +/- 0.49 mm of separation; ibuprofen 2.56 +/- 0.11 mm, and the control and acetaminophen groups exhibited similar degrees of tooth separation: 3.31 +/- 0.07 mm and 3.31 +/- 0.08 mm, respectively. A highly significant difference occurred between the mean rates of tooth separation among the various drug groups after day 8 (P < 0.001). Results of this study suggest that acetaminophen is the analgesic of choice for the relief of minor discomfort associated with orthodontic treatment.

Acetaminophen↗

PubMed1999

Orthodontic treatment of openbite and deepbite high-angle malocclusions.

The aim of the investigation was to assess the effect of orthodontic treatment on dentoskeletal morphology in children with openbite and deepbite high-angle malocclusion. Subjects (n = 54) in the mixed dentition with a hyperdivergent mandibular plane angle (high-angle, NSL/ML > or =40 degrees) were surveyed. Pre- and posttreatment lateral roentgenographic cephalograms were analyzed. Subjects were divided into three subgroups according to the amount of pretreatment overbite: < 0 mm = insufficient/no compensation (openbite); 0-4 mm = acceptable compensation (normal overbite); >4 mm = overcompensation (deepbite). Pretreatment, 20% of the high-angle cases exhibited insufficient dentoskeletal compensation (overbite <0 mm), and 35% displayed overcompensation (overbite >4 mm). Influences of habits such as lip sucking and tongue-thrust swallowing were more common in the openbite group. No major difference in treatment approach could be found between subgroups. In 82% of the openbite group and 90% of the deepbite group, overbite was corrected by orthodontic treatment. The mandibular plane angle was unaffected in both groups. The mechanisms of overbite correction differed between groups. The openbite group exhibited a significant decrease in interjaw-base angle. Increases in anterior and posterior dentoalveolar heights were comparable. The deepbite group showed no significant changes in skeletal morphology. The increase in dentoalveolar height was approximately twice as large posteriorly as anteriorly. The majority of children (80%) with high-angle morphology had a positive pretreatment overbite, thus exhibiting compensation of jaw-base hyperdivergency. Orthodontic treatment of high-angle malocclusions did not influence the mandibular plane angle in openbite or deepbite cases. Overbite correction was accomplished by tipping the maxilla downward anteriorly in openbite subjects, and by controlling incisor eruption in deepbite subjects.

Cephalometry↗

PubMed1999

Craniofacial imaging in orthodontics: historical perspective, current status, and future developments.

Rapid and substantial advances in imaging methods and technology have not always been expediently or adequately communicated to the practicing orthodontist. In this review we highlight contemporary imaging techniques and innovations in imaging that, in the future, are likely to greatly improve the depiction of craniofacial structures for use in diagnosis and treatment planning. In order to provide an appropriate background for this topic, we first discuss the evolution of craniofacial imaging in orthodontics and review the limitations of current methods, including the two-dimensional representation of three-dimensional anatomy, depiction as a patchwork of site-specific images, associated geometric errors, and images that have a limited point of view and are static in space and time. Three-dimensional computed tomography can be considered a partial solution to these limitations, but imaging costs, radiation exposure, and lack of soft tissue representation may make it unacceptable for routine orthodontics. A more complete solution might be achieved through digital processing of contemporary imaging technologies that would extend their capabilities, overcome many of their limitations, and result in an increase in the amount of relevant information obtained. Digital processes are currently being developed that create accurate multidimensional models that integrate form and function. These models will be interactive, linked to knowledge databases, and will provide the clinician with answers to pertinent questions. These advances in imaging are likely to enhance the accuracy and reliability of orthodontic diagnosis and treatment planning, and will be of importance in both clinical practice and research.

Cephalometry↗

PubMed2000

Orthodontic tooth movement in the prednisolone-treated rat.

Adverse effects of corticosteroids on bone metabolism raise concerns as to whether steroid treatment may influence orthodontic movement. This study examined the effect of prednisolone on orthodontic movement using an established rat model. The corticosteroid treated group (N = 6) was administered prednisolone (1 mg/kg) daily, for a 12-day induction period; the control group (N = 6) received equivalent volumes of saline. On day 12, an orthodontic appliance was placed which exerted 30 g of mesial force to the maxillary first molar. Animals were sacrificed on day 24 and tooth movement was measured. Sagittal sections of the molars were stained with haematoxylin and eosin, and for tartrate-resistant acid phosphatase (TRAP) activity. While there were no significant differences in the magnitude of tooth movement between the 2 groups, steroid-treated rats displayed significantly less root resorption on the compression side and fewer TRAP-positive cells within the PDL space on the same side. This suggests steroid treatment suppressed clastic activity.

Acid Phosphatase↗

PubMed2000

The effect of repeated bonding on the shear bond strength of a composite resin orthodontic adhesive.

One of the problems clinicians face during treatment is bracket failure. This is usually the result either of the patient's accidentally applying inappropriate forces to the bracket or of a poor bonding technique. As a result, a significant number of teeth have to be rebonded in a busy orthodontic practice. The purpose of this study was to evaluate the effect of repeated bonding on the shear bond strength of orthodontic brackets. Fifteen freshly extracted human molars were collected and stored in a solution of 0.1% (wt/vol) thymol. The teeth were cleaned, polished, and etched with a 37% phosphoric acid gel. The brackets were bonded with the adhesive and light cured for 20 seconds. The teeth were sequentially bonded and debonded 3 times with the same composite orthodontic adhesive. At each time, all 15 teeth were debonded within a half hour after bonding to simulate the clinical condition at which a newly bonded bracket is attached to the arch wire. The results of the analysis of variance comparing the shear bond strength at the 3 debonding attempts indicated the presence of no significant differences among the 3 groups (P = .104). However, when the overall change in shear bond strength within each tooth was evaluated between debonding sequences 1 and 3, 10 teeth had a significant (P = .001) decrease (mean +/- SD, -4.6+/-2.5 MPa) in bond strength, whereas 5 teeth had a significant (P = .02) increase (mean +/- SD, 2.8+/-1.6 MPa). The present findings indicated that in general, the highest values for shear bond strength were obtained after the initial bonding. Rebonded teeth have significantly lower and inconsistent shear bond strength; ie, bond strength may further decrease or increase after the second debonding, and the changes in bond strength may be related to the changes in the morphologic characteristics of the etched enamel surface as a result of the presence of adhesive remnants.

Analysis of Variance↗

PubMed2001

Orthodontic in vivo bond strength: comparison with in vitro results.

The purpose of the present study was to test a new in vivo debonding device and compare in vivo bond strengths recorded by this device with in vitro bond strengths recorded by a universal testing machine such as the Instron. For the in vitro part of the study, 60 extracted premolar teeth were divided into 2 groups of 30 each. Both groups of 30 teeth had 3M Unitek Victory Twin brackets, precoated with Transbond XT composite resin, bonded to them. Shear bond strength tests were carried out in vitro using the universal testing machine on one group of 30 teeth while the debonding device was used on the other group of 30 teeth. The mean shear bond strength of the group debonded using the universal machine was 11.02 MPa and that of the group debonded with the debonding device was 12.82 MPa. For the in vivo part of the study, 8 patients randomly assigned to the research clinician from patients in The University of Alabama School of Dentistry, Department of Orthodontics, had a total of 60 premolar teeth bonded with 3M Unitek Victory Twin brackets. Following comprehensive orthodontic treatment (average time of 23 months), shear bond strength tests were carried out using the debonding device, which can measure debonding forces in vivo. The mean shear bond strength recorded in vivo was 5.47 MPa. Statistically significant differences were found between all 3 groups tested. The results appear to indicate that mean bond strengths recorded in vivo following comprehensive orthodontic treatment are significantly lower than bond strengths recorded in vitro.

Analysis of Variance↗

PubMed2001

Orthodontic outcomes assessment using the peer assessment rating index.

The purpose of the present study was to gain more information on the assessment of orthodontic treatment using the PAR Index. The PAR Index was used to assess the study casts of 54 cases treated by 5 orthodontists who successfully completed Phase III of the American Board of Orthodontics. These peer-reviewed cases were considered to represent a subjective opinion of an excellent treatment standard. The PAR scores for the Board-accepted cases were then compared with the PAR scores of 51 cases consecutively treated by orthodontic graduate students. The pretreatment, posttreatment, and percent changes in PAR scores for the Board cases and the graduate student-treated cases were compared. The PAR Index scores and treatment duration were analyzed for the entire sample using general linear models techniques. Results of the study showed no statistically significant difference between the Board-accepted cases and the graduate student-treated cases for any single component of the PAR Index at either the pretreatment or posttreatment times. However, the percent reduction in the mean PAR score for the Board-accepted cases was significantly more than the reduction for the graduate student-treated cases (87.9%+/-9.5% vs 81.7%+/-15.3%). Analysis of treatment duration showed that a higher pretreatment PAR score and a greater percent reduction in PAR score were significantly associated with longer treatment durations.

Episode of Care↗

PubMed2001

Nickel and chromium levels in the saliva and serum of patients with fixed orthodontic appliances.

The aim of this study was to evaluate the concentrations of nickel and chromium ions in salivary and serum samples from patients treated with fixed orthodontic appliances. A second aim of this study was to determine any significant changes in these concentrations during any period of the treatment time. Saliva and blood samples were collected from 100 patients ranging in age from 12 to 33 years. Twenty samples from each group were obtained. The groups were as follows: In the first group, saliva and blood samples were collected before insertion of the fixed appliances. In the second, third, fourth, and fifth groups, samples were collected at 1 week, 1 month, 1 year, and 2 years after appliance insertion. The serum was prepared by centrifuging the blood samples at 3000 rpm for 10 minutes. The fixed appliances consisted of an average of 4 bands and 20 bonded brackets. No palatal or lingual appliances welded to bands or extraoral auxiliary appliances were used. The spectrophotometric determinations were carried out using electrothermal atomic absorption spectrophotometry. The results indicated certain differences in the amounts of nickel and chromium released from fixed orthodontic appliances during different periods of treatment. The Mann-Whitney U-test from the SPSS statistics program was used to analyze the significance of the differences between no-appliance samples and those obtained with the appliances present. In the serum, there were statistically significant increases in ion concentration in the second-year groups. In saliva samples, nickel and chromium reached their highest levels in the first month and decreased to their initial level in the rest of the groups. It can be concluded that fixed orthodontic appliances release measurable amount of nickel and chromium when placed in the mouth, but this increase doesn't reach toxic levels for nickel and chromium in the saliva and serum.

Adolescent↗

PubMed2003

Assessing the performance of a methyl methacrylate-based resin cement with self-etching primer for bonding orthodontic brackets.

Questions over the usefulness of a self-etching primer with resin adhesive in the bonding of orthodontic brackets remain unsolved. The purpose of this study was to determine the effects of using Multibond, a new methyl methacrylate (MMA)-based resin cement with self-etching primer, on the shear bond strength of orthodontic brackets compared with Superbond C&B, which is a well-known MMA-based resin cement containing phosphoric acid etching. Metal or plastic brackets were bonded to etched or self-etching primed bovine teeth using Superbond C&B or Multibond. The shear bond strengths were measured after immersion in water at 37 degrees C for 24 hours. Data were analyzed by two-way analysis of variance and Scheffe's test. The surface appearances of the teeth after phosphoric acid etching or self-etching priming were observed by field-emission scanning electron microscopy (FE-SEM). Metal brackets bonded with Multibond had a significantly lower shear bond strength than metal brackets bonded with Superbond C&B. No significant differences in shear bond strength were observed between Multibond and Superbond C&B when plastic brackets were bonded to the enamel. The shear bond strength of metal brackets bonded with Multibond was comparable with that of plastic brackets bonded with Superbond C&B. Adhesive remnant index score showed a tendency of more residual resin cement remaining on the teeth when metal brackets were bonded with Multibond. FE-SEM observation revealed less dissolution of the enamel surface resulting from treatment with Multibond self-etching primer as compared with phosphoric acid. Thus, the Multibond system may be a candidate for bonding orthodontic brackets with the advantage of minimizing enamel loss.

Acid Etching, Dental↗

PubMed2003

A 20-year follow-up of signs and symptoms of temporomandibular disorders and malocclusions in subjects with and without orthodontic treatment in childhood.

This investigation analyzes the influence of orthodontic treatment on signs and symptoms of temporomandibular disorders (TMDs) and different malocclusions during a 20-year period. Originally, 402 randomly selected 7-, 11-, and 15-year-old subjects were examined clinically and by means of a questionnaire for signs and symptoms of TMDs. The examination was repeated after five and ten years. After 20 years, 320 subjects (85% of the traced subjects) completed the questionnaire. The oldest age group,now 35 years of age, was invited to a clinical examination, and 100 subjects (81% of the traced subjects) were examined. The correlations between signs and symptoms of TMD and different malocclusions were mainly weak, although sometimes statistically significant. Lateral forced bite and unilateral crossbite were correlated with TMD signs and symptoms at the 10- and 20-year follow-ups (r = 0.38, P < .05 and r = 0.34, P < .01, respectively). Subjects with malocclusion over a long period of time tended to report more symptoms of TMD and to show a higher dysfunction index, compared with subjects with no malocclusion at all. There were no statistically significant differences in the prevalence of TMD signs and symptoms between subjects with or without previous experience of orthodontic treatment. This 20-year follow-up supports the opinion that no single occlusal factor is of major importance for the development of TMD, but a lateral forced bite between retruded contact position (RCP) and intercuspal position (ICP), as well as unilateral crossbite, may be a potential risk factor in this respect. Furthermore, subjects with a history of orthodontic treatment do not run a higher risk of developing TMD later in life, compared with subjects with no such experience.

Adolescent↗

PubMed2004

Effect of light-emitting diode on bond strength of orthodontic brackets.

The aim of this study was to evaluate the effect of light-emitting diode (LED) light curing on shear bond strength (SBS) of orthodontic brackets bonded to teeth. Light exposure of 40 seconds from a conventional halogen-based light-curing unit was used as a control. Eighty human premolars were divided into four groups of 20 each. Brackets were bonded to acid-etched teeth with Transbond XT light-cured adhesive. In the first group, the adhesive was light cured for 40 seconds with a conventional halogen unit (XL3000, 3M). In the other three groups, adhesive was cured with a commercial LED unit (Elipar FreeLight, 3M ESPE) for 10, 20, or 40 seconds. SBS of brackets was measured on a universal testing machine and recorded in megapascals. Adhesive remnant index (ARI) scores were determined after failure of brackets. Data were analyzed using analysis of variance and chi-square tests. No statistically significant differences were found among the SBS values of halogen-based light-cured (13.1 +/- 3.1 MPa) and 20- and 40-second LED-cured (13.9 +/- 4.8 MPa and 12.7 +/- 5.1 MPa) specimens (P > .05). However, 10 seconds of LED curing yielded significantly lower SBS (P < .05). No statistically significant differences were found between the ARI scores among groups. The results of this study are promising for the orthodontic application of LED-curing units, but further compatibility and physical characteristic studies of various orthodontic adhesives and clinical trials should be performed before validation.

Dental Bonding↗

PubMed2004

Nonlinear behavior of search strategies for identifying relevant orthodontic articles.

The communication process with electronic literature databases permitting a freetext search is prone in part to nonlinear, chaotic behavior. Even very minor changes in the initial conditions (search query) have a dramatic impact on the concluding event (search outcome). This statement has been verified with reference to alterations to the term "orthodontic" in search strategies of published systematic reviews. The results showed that a variation in one letter led to an average of 152 papers, 81% of them of orthodontic relevance, failing to be localized. Yet, the opposite effect, the elimination of papers (-418), was also observed, confirming the underlying nonlinear pattern. Search queries for orthodontic articles should invariably be equipped with the robust truncation "orthodon*." Truncation variants of key words should be used as a matter of principle to verify the outcome.

Databases, Bibliographic↗

PubMed2004

Degradation in performance of orthodontic wires caused by hydrogen absorption during short-term immersion in 2.0% acidulated phosphate fluoride solution.

The purpose of this study was to investigate the degradation in performance of four major alloys of orthodontic wires, namely nickel-titanium, beta titanium, stainless steel, and cobalt-chromium-nickel, caused by hydrogen absorption during short-term immersion in an acid fluoride solutions. The hydrogen-related degradation of orthodontic wires after immersion in 2.0% acidulated phosphate fluoride solution at 37 degrees C for 60 minutes was evaluated by a tensile test, scanning electron microscope observation, and hydrogen thermal desorption analysis. Upon immersion, the tensile strengths of the nickel-titanium and beta titanium wires decreased. Particularly, the nickel-titanium wire fractured before yielding, and the fracture mode changed from ductile to brittle. The amounts of absorbed hydrogen in the nickel-titanium and beta titanium wires were 200 and 100 mass ppm, respectively. On the other hand, the tensile strengths of the stainless steel and cobalt-chromium-nickel wires were only slightly affected by immersion. The results of this study suggest that degradation in performance of orthodontic wires of titanium alloys occurs because of hydrogen absorption even after a short-term immersion in fluoride solutions.

Acidulated Phosphate Fluoride↗