There is no pulp necrosis or calcific metamorphosis of pulp induced by orthodontic treatment: biological basis

Clear aligners with differentiated thickness and without attachments - A case report

Background

Most clear aligner systems use straight or scalloped gingival margin aligners that are replaced weekly and that mainly use attachments to guide many movements. Yet in the literature some studies show the effectiveness of the aligner margin extended beyond the gingival margin, and divots instead of attachments and the biological advantage given by the use of aligners with differentiated thickness.

Material and Methods

A female patient (23 years old) with a pronounced proclination of the upper and lower incisors and moderate crowding who was treated with aligners weekly replaced with differentiated thickness, divots, no attachments and a straight margin beyond the gingival margin.

Results

The therapy was carried out in 5 months and did not need any refinements. A total of 40 aligners were used (20 with soft thickness and 20 with hard thickness for each arch).

Conclusions

Invisible aligners without attachments and with other therapeutic strategies such as divots and differentiated thickness are a valid alternative to traditional aligners that cannot be ignored. Key words:Orthodontics, clear aligners, appliances design.

Response to Pulp Vitality Tests in Teeth Submitted to Orthodontic Movement, Adjacent to the Cleft Area

OBJECTIVE

To evaluate the pulp vitality in teeth adjacent to the cleft area submitted to orthodontic movement into the alveolar graft area in individuals with complete unilateral cleft lip and palate (CUCLP).

DESIGN

Cold sensitivity, vertical, and horizontal percussion tests were conducted on the teeth adjacent to the cleft and the contralateral teeth.

SETTING

Endodontics Sector in the Hospital for Rehabilitation of Craniofacial Anomalies, University of São Paulo (HRAC/USP).

PATIENTS

One hundred patients with CUCLP and hypodontia of the upper lateral incisor in orthodontic movement and after successful alveolar bone graft in the cleft area.

MAIN OUTCOME MEASURES

The cleft study group (SG) was composed of 200 teeth, adjacent to the cleft area. The control group (CG) consisted of 200 contralateral teeth. Statistical analysis was performed using the chi-square test for comparisons between groups (P < .05).

RESULTS

In the SG, 82.0% of teeth presented positive response to the cold sensitivity testing, 13.5% had negative response, and 4.5% had marked response, with statistically significant difference in relation to the CG. The vertical and horizontal percussion tests on teeth in the SG revealed the same results, in which 95.0% presented negative response and 5.0% responded positively, without significant difference compared to teeth in the CG, for both tests.

CONCLUSIONS

Teeth adjacent to the cleft area presented changes in the physiological conditions of the pulp, which were observed by reduction of positive response to the cold sensitivity testing or presence of pulp hypersensitivity in cases of marked response.

Pulp sensitivity changes during orthodontic treatment at different time periods: a prospective study

Objective

The purpose of this investigation was to recognize pulp sensitivity changes in teeth receiving orthodontic treatment by means of an electric pulp tester (Vitality Scanner Model 2006; Kerr Corporation, Brea CA, USA).

Materials and methods

An electric stimulus response threshold of eight teeth in 22 patients was measured prior to positioning orthodontic attachments, immediately before ligation of a nickel titanium archwire, immediately after ligation of a stainless steel archwire and 9 to 15 months after having achieved the clinical purposes established with the nickel titanium archwires. The first measurement served as baseline.

Results

All teeth responded to an electrical stimulus at all times. No statistical differences were observed between the response thresholds obtained at different treatment times. The mean response threshold of the second measurement showed a decreasing response threshold tendency when compared with those of the baseline measurement. The mean response threshold of the third measurement showed an increasing tendency when compared with those of the baseline measurement. The first maxillary incisor and canine showed the lowest decreasing response threshold after the second measurement and the highest increasing response threshold after the third measurement. Less noticeable, but similar decreasing and increasing response threshold tendencies were observed in all other teeth after the second and third measurements, respectively.

Conclusions

The results obtained in this investigation suggest that pulp sensitivity can be monitored during orthodontic treatment by means of an electric pulp tester.

Clinical relevance

The importance of monitoring the pulp status during orthodontic treatment.

Human Dental Pulp Tissue during Orthodontic Tooth Movement: An Immunofluorescence Study

The orthodontic tooth movement is the last step of several biological processes that take place after the application of external forces. During this process, dental pulp tissue is subjected to structural and protein expression modifications in order to maintain their integrity and functional morphology. The purpose of the present work was to perform an in vivo study, evaluating protein expression modifications in the human dental pulp of patients that have undergone orthodontic tooth movement due to pre-calibrated light force application for 30 days. Dental pulp samples were extracted from molars and premolars of the control group and after 7 and 30 days of treatment; the samples were then processed for immunofluorescence reactions using antibodies against fibronectin, collagen I and vascular endothelial growth factor (VEGF). Our results show that, after 7 days of treatment, all tested proteins change their pattern expression and will reset after 30 days. These data demonstrate that the dental pulp does not involve any irreversible iatrogenic alterations, supporting the efficacy and safety of using pre-calibrated force application to induce orthodontic tooth movement in clinical practice.

Orthodontics and Endodontics: clinical decision-making

Endodontically treated teeth may be moved, as endodontic treatment is not a contraindication for orthodontic treatment. Apical periodontal repair begins when the periapical or pulp lesion has completely resolved. This may happen immediately after treatment if the filling material causes little or no irritation of periapical tissues, and particularly if the material is fully contained within the canal. When it leaks, a foreign body granuloma forms and persists for some months or indefinitely, depending on the composition of the filling material. Materials containing calcium hydroxide with no resin components undergo phagocytosis and disappear in some months, as macrophages gradually remove them. Materials containing resins, silicone, ionomers, zinc oxide-eugenol, bioceramics or gutta-percha remain in the site and induce the formation of foreign body granulomas. Although this does not preclude tooth movement, patients should be followed up every three months using periapical images to control the position of the material in relation to the tooth apex. “Pseudo” overfilling may be avoided if permanent filling is delayed until the time when orthodontic treatment is completed.