Extração seriada: considerações clínicas / Serial extraction: clinical considerations

O tratamento “precoce” das más-oclusões tem despertado interesse crescente da comunidade ortodôntica. Dentre estes, destaca-se a extração seriada que visa conciliar as diferenças entre a quantidade conhecida do material dentário e a deficiência permanente do osso de suporte. A técnica é aplicada na dentadura mista, por meio de uma sequência pré-determinada de exodontias entre dentes decíduos e permanentes, na busca do alinhamento imediato, de preferência espontâneo, dos dentes permanentes remanescentes com uma terapia ortodôntica mecânica mínima. Será relatado um caso clínico no qual foi realizada a extração seriada em um paciente com má-oclusão de Classe I, em crescimento, com apinhamento severo e biprotruso. Todos os objetivos estéticos e funcionais foram alcançados...

The early malocclusion treatment has increased interest of orthodontic community. Among these is the serial extraction that harmonizes the differences between the amount of dental material and permanent deficiency of supporting bone. The technique is applied in mixed dentition through a predetermined sequence of extractions between deciduous and permanent teeth, in order to reach spontaneous immediately alignment of remaining permanent teeth with a minimum orthodontic mechanics. It will be reported a case where the serial extraction was performed in a growing patient with biprotrusion, Class I malocclusion and severe crowding. All functional and aesthetics goals were reached...

External apical root resorption in patients treated by serial extractions followed by mechanotherapy.

INTRODUCTION: In the course of orthodontic treatment with serial extractions (SE), spontaneous unraveling of crowded incisors occurs. It was hypothesized that SE followed by mechanotherapy will cause less external apical root resorption (EARR) than orthodontic treatment with late extractions (LE). METHODS: The records of 24 patients who underwent SE and mechanotherapy and 24 control patients who underwent LE and mechanotherapy were examined. The groups were matched for sex, central incisor root development and morphology, malocclusion class, ANB angle, and overjet. Lateral cephalograms taken before mechanotherapy (T1) and after mechanotherapy (T2) were traced and superimposed on the palatal plane with registration on the osseous details superior to the maxillary incisors and on the palatal curve. The T1 and T2 central incisor lengths, changes in the axial inclination, and horizontal and vertical apical movements were measured. RESULTS: The tooth lengths in both groups were reduced: the EARR values were 1.8 mm (± 1.1) in the SE group and 2.1 mm (± 1.4) in the LE group, and the difference between the groups was not significant. The movements of the teeth in both groups were similar in absolute values. CONCLUSIONS: The spontaneous unraveling of incisor crowding with SE treatment does not prevent the common EARR seen in patients treated with LE, when the patients are treated by mechanotherapy after the SE.

Medición de pérdida de anclaje en los pacientes tratados con extracciones de primeros premolares superiores e inferiores en la clínica de ortodoncia de postgrado de la facultad de odontología de la UNAM en el lapso 1998-2001 / Mensuration of lost of anchorage in the patients treaties with extractions of first superior and inferior premolares in the clinic of orthodontics of graduate degree of the ability of dentistry of the UNAM in the lapse of 1998-2001

El presente estudio fue ralizado con la finalidad de evaluar el control de anclaje posterior maxilar mandibular con el uso del Botón de Nance, Arco Lingual y Anclaje Diferencial. La muestra consistió en cefalografías pretratamiento y postratamiento de 59 pacientes que requirieron extracciones de primeros premolares y usaron algún tipo de auxiliar de anclaje. Se utilizó la sobreimposición de Bjork para evaluar el movimiento del primer molar. Para comparar los resultados entre los diferentes grupos de anclajes cefalométricos, fue usado el análisi de varianza (ANOVA), en los cuales hubo una pérdida de anclaje maxilar de 3.01 mm y mandibular 2.61 mm. Adicional a esto no hubo diferencias estadísticamente significativas de pérdida de anclaje ocurrida entre los diferentes auxiliares. Según los resultados de este estudio, los auxiliares de anclaje no pueden ser utilizados en aquellos casos de pacientes que necesiten un anclaje máximo, ya que permiten mesialización molar hasta casi la mitad del espacio de las extracciones

Evaluation of apical root resorption following extraction therapy in subjects with Class I and Class II malocclusions.

The purpose of this study was to determine the amount of root resorption during orthodontic treatment, and to examine the relationship between tooth movement and apical root resorption. Twenty-seven Class I and 27 Class II patients treated with edgewise mechanics following first premolar extractions were selected. The following measurements were made on the pre- and post-treatment cephalograms: upper central incisor to palatal plane distance, the inclination of upper central incisor to the FH and AP planes, the perpendicular distances from the incisor tip to the AP and PTV planes, and incisor apex to PTV. The amount of apical root resorption of the maxillary central incisors was determined for each patient by subtracting the post-treatment tooth length from the pre-treatment tooth length measured directly on cephalograms. Intra-group differences were evaluated by the Student's t-test and inter-group differences by the Mann-Whitney U-test. For correlations the Pearson correlation coefficient was used. The results show that there was a mean of approximately 1 mm (P < 0.01) of apical root shortening in Class I patients, but in Class II division I subjects the mean root resorption was more than 2 mm (P < 0.001). The inter-group differences were statistically significant. No significant correlations were found between the amount of apical root resorption and tooth inclination, or the duration of active treatment.

Postretention mandibular incisor stability after premolar serial extractions.

The purpose of this study was to evaluate the mandibular incisor alignment in serial extraction cases, using the longitudinal dental cast records of the Burlington Growth Center as a control sample. Various parameters were investigated and the statistical differences determined between the treated and untreated groups. The results were also compared with data from serial extraction groups that subsequently had orthodontic treatment. Untreated subjects and subjects treated only with serial extractions showed similar longitudinal changes. However, the extraction group that also received orthodontic treatment appeared to show more lower incisor crowding long-term. No predictors for stability of clinical significance could be determined. Mechanotherapy influences the craniofacial and dentoalveolar dimensions, which appear to cause more long-term lower incisor crowding.

La extracción prematura de dientes anteriores inferiores temporales y su repercusión en el desarrollo de la oclusión / The premature extraction of anterior temporary lower teeth and its repercussion in occlusal development

Se presenta una revisión de la literatura acerca de la repercusión que puede tener en el desarrollo de la oclusión y de la mandíbula, la extracción prematura de dientes anteriores inferiores primarios y se concluye que la decisión de extraer esos dientes debe estar basada en un buen diagnóstico y plan de tratamiento

[The relationships between orthodontics and temporomandibular joint dysfunction. A review of the literature and longitudinal study]. / Zusammenhänge zwischen Kieferorthopdie und Kiefergelenksdysfunktion. Literaturübersicht und longitudinale Untersuchung.

The fist part of this study concerns a literature review on temporomandibular dysfunction (TMD). There exists an equal amount of literature relating occlusal interferences to TMD, as there are reports denying any causal relationship. It is remarkable, however, that the latter reports are relatively recent. The relationship between the Angle classification and TMD is reported to be only weak in a "normal" orthodontic population. The relationship between morphologic malocclusion, e.g. deep bites or crossbites, with TMD seems to be somewhat stronger. The vast majority of the reports did not find any relationship between TMD and orthodontic treatment or extractions. Our own longitudinal prospective study could not reveal any systematic relationship between orthodontic treatment or extractions and TMD.

Long-term effects of orthodontic treatment, including extraction, on signs and symptoms attributed to CMD.

The prevalence of signs and symptoms attributed to craniomandibular disorders (CMD) was established in an orthodontically treated sample. The effect of orthodontic therapy upon this prevalence was studied by monitoring three groups of patients whose treatment procedures were different. The first group was treated with functional appliances, the second with Begg light wire, and the third with chin cups. In addition, the effect of extraction upon the prevalence was studied by monitoring three groups in which different extraction decisions had been made: four first premolars extracted, all other types of extraction, and no extraction. Based upon the finding of similar prevalences after 20 years of observation, it appears that neither orthodontic treatment nor extraction has a causal relationship with the signs and symptoms of CMD recorded during this study.

Orthodontic risk factors for temporomandibular disorders (TMD). I: Premolar extractions.

Concern about claims that premolar extractions may put patients at risk for temporomandibular disorders (TMD) led to this study. We report first findings from a longitudinal study of orthodontic patients begun in 1983. By using the methods of Helkimo, we collected TMD data before initiation of orthodontic treatment, between 0 and 12 months after debanding, and 12 to 24 months after debanding. Analyses related Helkimo scores with premolar extractions in 65 patients for whom orthodontic treatment had been completed. Twenty-six patients were treated without premolar extractions, 25 had four premolars extracted, and 14 had two upper premolars extracted. Tests for significance of differences between mean Helkimo scores were conducted for the nonextraction group compared with the extraction groups, and between pretreatment and posttreatment Helkimo scores for each group. Results included: (1) no significant intergroup differences between mean pretreatment or posttreatment scores, and (2) small but statistically significant (p less than 0.05) differences (in the direction of improvement) between mean pretreatment and posttreatment scores for both the nonextraction group and for the four premolar extraction group.

Orthodontics as a risk factor for temporomandibular disorders (TMD). II.

Debate about orthodontic treatment as a risk factor for temporomandibular disorders (TMD) led to this study. This report, the second in a series, concerns findings from a longitudinal study in which 30 new orthodontic patients have been enrolled annually since 1983. The method of Helkimo was used to collect TMD data before initiation of orthodontic treatment, and at annual intervals after debanding. Treatment was by fixed edgewise appliances. Data from a pretreatment and at least one posttreatment Helkimo examination were available for 109 patients. Follow-up data were available for 92 patients in the first year after debanding, with the corresponding sample sizes declining to 56, 33, 19, 11, and 7 for the second through the sixth posttreatment years, respectively. Primary analyses involved comparison of mean scores from the Helkimo 25-point dysfunction index scale. There were no significant differences between mean pretreatment and posttreatment Helkimo scores for any of the various groupings except for small, clinically unimportant improvements seen in the 12 to 24 month subgroup of 55 patients and in the 48 to 60 month subgroup of 11 patients. With average follow-up time of about 2 years for the 109 patients, 90% had Helkimo scores that stayed the same or improved, and 10% had scores that increased or worsened from 2 to 5 Helkimo points. We conclude that the orthodontic treatment experienced by our sample was not an important etiologic factor for TMD.

Relationship between orthodontic treatment, condylar position, and internal derangement in the temporomandibular joint.

The purpose of this study was to test the hypothesis that retraction of maxillary front teeth may lock the mandible in a posterior position, and to evaluate any relationship between condylar position and signs and symptoms of internal derangements in the temporomandibular joint. A total of 29 female patients treated for Angle Class II, Division 1 malocclusion with extraction of maxillary first premolars and 34 female patients treated for Angle Class I malocclusion without tooth extraction consented to participate in a radiographic and clinical follow-up examination. The mean ages of the patients were 16.9 (SD 3.0) and 16.6 (SD 2.6) years, and the mean times after treatment were 1.6 (SD 1.0) and 1.5 (SD 0.9) years, respectively. Condylar position was measured in percent anterior and posterior displacement from absolute concentricity on lateral, central, and medial tomographic sections of each joint. Mean condylar position was more posterior at right central (P less than 0.05) and medial (P less than 0.01) tomographic sections in patients treated with extraction. The difference was due to a higher frequency of anteriorly positioned condyles in the nonextraction cases. No intergroup differences in the sagittal occlusal slide from CR to CO and the number of patients with clicking were found. However, the condyles were located more posteriorly in all tomographic sections (P less than 0.05 for lateral, P less than 0.001 for central and medial) in patients with clicking than in those without.

[Extraction versus non-extraction. Does the pendulum swing too much?]. / Extractions versus non-extractions. Le pendule a-t-il trop oscillé?

Therapeutic extractions in Orthodontics has decreased in the last few years. The idea of that early treatment, functional appliances, upper molar and bicuspids distal movements, upper sagittal suture opening and other proceedings, reduce extraction practice is widely extended. Unfavorable effects like facial profile worsening and TMJ problems has been related to extractions. In this study common arguments against extractions has been analysed and attacked. Some cases are presented to illustrate non-extraction reliability. Main conclusions are: there is not relationship between extraction and TMJ dysfunctions; profile changes depend on technique not on extractions "per se"; profile gets better in alveolar prognatisms; non-extraction tendency rely most on some viewpoints away from biologic facts than clinical evidences.

Periodontal status of teeth facing extraction sites long-term after orthodontic treatment.

The present study was undertaken to examine the long-term periodontal status of teeth orthodontically moved into extraction sites. Patients were examined 14 to 34 years after active orthodontic treatment involving extraction of four first premolars. Three groups were established: one with closed tooth contacts and parallel adjacent teeth, one with closed tooth contacts and tipped adjacent teeth, and one with open contacts between adjacent teeth. Within each group accumulation of plaque, gingival health status, probing pocket depth, and probing attachment level of interproximal tooth surfaces, facing extraction sites and adjacent control sites between canine and lateral incisor were compared. Significantly more probing attachment loss was found in extraction sites with open tooth contacts (P less than 0.01) and with parallel adjacent teeth and closed tooth contacts (P less than 0.05) than in control sites. However, the mean differences were less than 0.5 mm, which may not be considered clinically significant. Tipping of teeth into the extraction sites had no long-term detrimental effect on the probing attachment level. No differences in accumulation of plaque and in gingival health status were observed.