The correlation between external apical root resorption and electric pulp test responses: a prospective clinical trial

ABSTRACT Objective: The current study investigated the correlation between pulpal sensitivity to the electric pulp tester (EPT) and external apical root resorption (EARR) in four types of maxillary anterior teeth of fixed orthodontic treatment patients. Methods: In this prospective cohort study, 232 anterior teeth of 58 patients (mean age 18.96 ± 6.13 years) treated with fixed orthodontic treatment were examined. The EPT readings were recorded at twelve time points immediately before archwire insertion. Root resorption of four maxillary incisors were measured by means of parallel periapical radiographs at three time intervals (six months interval from the start) through design-to-purpose software to optimize data collection. A multiple linear regression model and Pearson correlation coefficient were used to assess the association of EPT values and observed EARR (p< 0.05). Results: The highest level of EPT measurement was recorded at initial visit, and then there was a decreasing trend in EPT level during treatment for the next six and twelve months. There was another increasing trend after six months till the finishing time of the treatment. There was a significant correlation between changes in root length and time of recording the root length (p< 0.001). There was significant positive correlation between changes in EPT level and amount of observed root resorption (p< 0.001). Conclusion: The relative decrease in electric pulp test level could be a diagnostic sign of root resorption during orthodontic treatment. Further studies with longer follow up are needed to confirm the current results.

RESUMO Objetivo: O presente estudo investigou a correlação entre a sensibilidade pulpar ao teste pulpar elétrico (TPE) e a reabsorção radicular apical externa (RRAE) nos quatro dentes anteriores superiores de pacientes em tratamento ortodôntico com aparelho fixo. Métodos: Nesse estudo de coorte prospectivo, foram avaliados 232 dentes anteriores de 58 pacientes (idade média 18,96 ± 6,13 anos) tratados com aparelho ortodôntico fixo. As leituras do TPE foram registradas em doze tempos de avaliação, imediatamente antes da inserção dos arcos. As reabsorções radiculares dos quatro incisivos superiores foram aferidas por meio da média das radiografias periapicais, em três intervalos de tempo (em intervalos de seis meses desde o início) por um software desenvolvido para essa finalidade, com o intuito de otimizar a coleta de dados. Para aferir a associação entre os valores de TPE e as RRAE observadas (p< 0,05), foram utilizados o modelo de regressão linear múltiplo e o coeficiente de correlação de Pearson. Resultados: O nível mais alto das medidas do TPE foi registrado na primeira visita e, daí em diante, houve uma tendência de diminuição no nível do TPE durante o tratamento, nos seis a doze meses seguintes. Houve, também, outra tendência de aumento após os seis meses até o término do tratamento, além de uma correlação significativa entre as mudanças no comprimento radicular e o tempo de registro do comprimento radicular (p< 0,001), bem como uma correlação positiva significativa entre as mudanças no nível do TPE e a quantidade de reabsorção radicular observada (p< 0,001). Conclusão: Uma diminuição relativa no nível de sensibilidade ao teste pulpar elétrico pode ser um sinal diagnóstico de reabsorção radicular durante o tratamento ortodôntico. Estudos futuros com acompanhamentos mais longos são necessários para confirmar os presentes resultados.

Stability and Effects of Mandibular Symphyseal Distraction Osteogenesis: A Systematic Review.

Aims: Expanding mandibular arch for correcting transverse deficiency is a challenging problem in orthodontics. It is believed that mandibular symphyseal distraction osteogenesis (MSDO) is an attractive solution for this problem. The aim of the present study is to review available data regarding stability of MSDO and its effect on temporomandibular joint and teeth and their surrounding tissues, in a systematic approach. Study Design: The study is a systematic review of available evidence. Place and Duration of Study: Department of Orthodontics of Dental school at Shahid Beheshti University of Medical Sciences. From January 2014 to January 2015. Methodology: Electronic searching was done in Medline, Embase and CENTRAL databases. Published clinical studies and case series in English language which had used tooth borne, bone borne or hybrid distractors and had follow up period of 1 year or more were included. Review article, case reports, and letters were not included. Presence of samples with syndromic problems or mandibular cleft and simultaneous other surgical procedures in mandible were reasons for excluding articles. Data were extracted from selected articles. Risk of bias was assessed in articles. Results: A total of 77 articles were found, from which, 10 met the inclusion criteria. 5 articles had assessed stability and none had reported instability. The effect of MSDO on temporomandibular joint was evaluated in all of the included studies, all of them stating that MSDO would not cause permanent changes in temporomandibular joint status. Gingivitis, root injury, mobility, pseudopocket and irresponsiveness to cold stimulus were reported in 6 studies. Risk of bias was assessed to be high in the included studies. Conclusion: Within the limits of this review it is concluded that MSDO would be a stable procedure and it may not cause temporomandibular joint disorder, provided that proper technique is used. Risk of injury to tooth is not so common; however, great care should be taken in order to prevent these injuries. Well-designed randomized clinical trials are highly recommended to clarify these issues.