Effect of isotretinoin on induced tooth movement in rats.

INTRODUCTION: This study was performed to evaluate the effect of isotretinoin on tooth displacement and tissues related to induced tooth movement (ITM) in rats. METHODS: Wistar rats were randomly divided into 4 groups: vegetable oil (O; n = 40), 7.5 mg/kg isotretinoin (I; n = 40), vegetable oil + ITM (OM; n = 44), and 7.5 mg/kg isotretinoin and ITM (IM; n = 39). After the daily application of the solutions for 30 days, an orthodontic appliance was installed to mesially displace the maxillary first right molar (30 cN) of rats in the OM and IM groups. The animals were killed 2, 7, 14, or 21 days after placement of the devices. The animals in the O and I groups did not undergo ITM but were killed simultaneously. The animals were examined for tooth displacement, the neoformation of mature collagen, bone and root resorption, the presence of hyalinized areas, and trabecular bone modeling by microcomputed tomography. RESULTS: There was no difference in tooth displacement, the number of osteoclasts, the presence of hyalinized areas, or trabecular bone among the O, I, OM, and IM groups across the periods tested (P >0.05). A lower percentage of mature collagen was found in the IM group than in the OM group on day 7 (P <0.05). A lower frequency of root resorption was found in the IM group than in the OM group on days 2 and 21 (P <0.05). CONCLUSIONS: Isotretinoin at 7.5 mg/kg decreased root resorption in rats subjected to ITM.

Discontinuation of Denosumab as a Potential Cause of Generalized External Cervical Root Resorption: A Case Report.

Generalized occurrence of external root resorption in an adult patient is a rare finding. This case report describes external cervical root resorption extensively affecting the dentition that may be associated with the use and subsequent cessation of denosumab for the treatment of osteoporosis.

Multiple Cervical Root Resorption in a Young Adult Female Previously Treated with Chemotherapy: A Case Report.

Multiple idiopathic cervical root resorption is an aggressive form of external root resorption that occurs at the cementoenamel junction and can affect multiple teeth (a minimum of 3) throughout the entire dentition. Most of the individuals affected are healthy with noncontributory medical histories. The resorption is usually detected as an incidental finding on radiographs or during dental examination. This case report describes an adult female with multiple cervical root resorptions who had been treated with chemotherapy for ovarian cancer at 16 years old. Nine years later, a total of 12 teeth were diagnosed with cervical root resorption. All of the known causative factors for external cervical resorption were discarded. To our knowledge, this is the first case reported of multiple cervical root resorption related to chemotherapy.

Influence of nicotine on orthodontic tooth movement: A systematic review of experimental studies in rats.

OBJECTIVE: The objective of this systematic review was to assess the impact of nicotine administration on orthodontic tooth movement (OTM). METHODS: A systematic search was conducted in PubMed, Scopus, EMBASE, MEDLINE (OVID) and Web of Knowledge databases and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. Studies evaluating the influence of nicotine on OTM, and with the presence of a control group (OTM without nicotine administration), were included. Quality assessment of the selected studies was performed following the Animal Research Reporting in Vivo Experiment (ARRIVE) guidelines. RESULTS: Six of the initially identified 108 articles fulfilled the inclusion criteria and were selected. All included studies were performed in male rats, which underwent OTM with or without nicotine administration. Since there was a variation among the included studies regarding nicotine dosage and the duration and magnitude of force application during OTM only a qualitative analysis could be performed. The studies reported that nicotine administration accelerated OTM by inducing alveolar bone resorption around the moving teeth. It was also found that nicotine increased root resorption during experimental OTM. More standardized animal research or clinical studies are warranted to further evaluate the impact of nicotine on OTM. CONCLUSIONS: On an experimental level, nicotine exposure in rats jeopardizes OTM by increasing alveolar bone loss and root resorption. From a clinical perspective, further studies are needed to assess the impact of habitual use of tobacco products on OTM.

Multiple external cervical root resorptions after home whitening treatment: a case report.

Invasive multiple cervical root resorptions after vital tooth bleaching is a rare condition. The aim of this article is to present a case of multiple external cervical root resorptions (ECRR) after a misguided home whitening treatment. A 34 year old male patient presented with slight sensitivity and mobility in several teeth. Despite the manufacturer's recommendations, the patient used a 22% carbamide peroxide-based tooth bleaching gel at home for 4 days consecutively, at night, on the upper and lower arches. Clinical examination revealed gingival swelling, probing depths ranging 5-7 mm on the buccal and proximal surfaces, and grade 2 mobility of the teeth affected by ECRR. Radiographs revealed presence of ECRR in several teeth during initial examination, and development of multiple new lesions 6 months later. The teeth were subsequently extracted. Histological analysis showed multiple dentine lacunae and areas of dentine reparation. The careful use of these products can prevent sequelae such as those reported in this clinical case. As the vital bleaching has a variable success rate, patients should be informed through a consent form of the benefits and risks of tooth bleaching treatment.

Effects of alendronate on osteoclast formation and activity in vitro.

INTRODUCTION: Root resorption is a common complication after replantation following traumatic dental avulsion. Endodontic therapy combined with local and intracanal medications aims to avoid osteoclastic activity. In such cases, the application of alendronate (ALN), a bisphosphonate widely used for the treatment of bone disorders, could be of clinical relevance. This study evaluated alendronate biocompatibility on periodontal ligament cells as well as its effects on an in vitro osteoclastogenesis model. METHODS: Alendronate cytotoxicity (10(-3) to 10(-9) mol/L) in human periodontal ligament fibroblasts, human osteogenic sarcoma cells, and murine osteoclastic precursors (RAW 264.7) was analyzed using cell number determination, cell viability, and proliferation assays. ALN (10(-6) to 10(-12) mol/L) effects on RANKL-induced osteoclastogenesis of RAW cells were assessed by tartrate-resistant acid phosphatase (TRAP) staining and activity and real-time polymerase chain reaction. RESULTS: ALN at higher concentrations was cytotoxic for all cell types, inhibiting significantly the proliferation of human osteogenic sarcoma cells and human periodontal ligament fibroblasts (≥10(-5) mol/L). TRAP activity and expression of the osteoclast markers TRAP and cathepsin K by RAW-derived osteoclasts decreased significantly with ALN at low concentrations, reaching the maximum effect at 10(-10) mol/L. CONCLUSIONS: We showed that ALN at very low concentrations is an effective inhibitor of RANKL-generated osteoclasts, without causing cytotoxic effects on their precursors or periapical cells. ALN at such concentrations might be useful to prevent replacement resorption in avulsed teeth.

Actualización en ortodoncia y bifosfonatos: consideraciones clínicas y experimentales / An update on biphosphonates: clinical and experimental considerations

Los bisfosfonatos son fármacos utilizados para el tratamiento de enfermedades que afectan al metabolismo óseo, principalmente para el tratamiento de la osteoporosis, siendo ésta la principal causa de prescripción médica de los mismos. Actualmente, no se encuentran esclarecidas las posibles complicaciones o riesgos implícitos del tratamiento ortodóntico aplicado a pacientes que reciben o han recibidobisfosfonatos. Dada la demanda actual, con un elevado número de pacientes que se encuentran en la búsqueda de un tratamiento ortodóntico muchos de los cuales son y/o han sido tratados con bisfosfonatos para la osteoporosis, es de relevancia conocer el efecto de laaplicación de fuerzas ortodónticas en un tejido óseo que ha sido tratado con dichas drogas. Por lo antedicho, el objetivo de este trabajo, ha sido realizar una actualización sobre los nuevos conocimientos emergentes de las últimas publicaciones científicas provenientes de trabajos clínicos como así también experimentales que asocien la ortodoncia y los bisfosfonatos. Para ello se realizó una exhaustiva búsqueda de información en la base de datos de Pubmed. La búsqueda obtenida reveló que en los pacientes que reciben y/o han recibido bisfosfonatos y son tratados ortodónticamente se observa una disminución del movimiento dentario, escasa obtención de paralelismo radicular y, en los casos con exodoncias previas aparición de áreas de esclerosis ósea. No fueron descriptos casos en los que se viera asociada la aparición de osteonecrosis de los maxilares. Por su parte, los estudios experimentales, obtuvieron resultados orientados en el mismo sentido, avalando los resultados clínicos...

Analysis of effect of non-steroidal anti-inflammatory drugs on teeth and oral tissues during orthodontic treatment. Report based on literature review.

In view of high availability and diversity of non-steroidal anti-inflammatory drugs (NSAIDs) on Polish market it is important for orthodontists to be aware of NSAID effect on the range of orthodontic tooth movement as well as the risk of root resorption in the moved teeth and other adverse effects, which might occur within oral cavity. The disadvantages of NSAID non-selective inhibition of COX include common oral inflammatory conditions, gingival bleeding, and disturbances of salivary secretion. Both, the selective and non-selective COX inhibitors, meloxicam excluded, used to alleviate the pain of orthodontic tooth movement, impede the movement of teeth. Paracetamol, explicitly indicated by most authors as the safest NSAID, seems to be the drug of choice in view of no influence on the range of tooth movement, the risk of root resorption or other adverse effects within oral cavity.

Icariin enhances the healing of rapid palatal expansion induced root resorption in rats.

Icariin has been reported to enhance bone healing and treat osteoporosis. In this study, we examined the effect of Icariin on rapid palatal expansion induced root resorption in rats. Our hypothesis is that Icariin can enhance the healing of rapid palatal expansion induced root resorption. Forty-eight male Wistar rats were divided randomly and equally into three groups (n=16 rats each). The rats were untreated (negative control) or treated with rapid palatal expansion without (positive control) or with Icariin at 2.5 mg/kg day (Icariin-treated groups). An initial force of 50×g was applied to the areas between the right and left upper first molars of the rats for 21 days. Eight rats were randomly chosen from each group, and the root resorption index (RRI) was determined with scanning electron microscopy (SEM). Upper first molar-centered buccal- lingual tissue slices were generated from the upper first molars and peridentium of the remaining eight rats from each group. Specimen slices were analyzed with HE and tararate-resistant acid phosphatase staining, osteoprotegerin (OPG) and receptor activator of nuclear factor kappa-B ligand (RANKL) immunohistochemistry, and optical microscopy. Analyses of cell number, densitometry, and one-way analysis of variance were performed. The Icariin-treated groups displayed decreased RRI values, decreased osteoclast numbers and activity levels, and increased OPG/RANKL expression ratios. High-power SEM revealed reparative cementum in the Icariin-treated samples. Icariin regulates osteoclast differentiation via the OPG/RANKL ratio, evoking a reparative effect on rapid palatal expansion induced root resorption in rats.

Resposta imune a agentes clareadores e reparadores dentais / Immune reponse to dental bleaching agents and repairers

Embora eficientes quanto ao aspecto estético, as técnicas de clareamento endógeno ainda apresentam graus variáveis de toxidade e muitas vezes podem levar ao desenvolvimento de reabsorção cervical inflamatória. Neste estudo, avaliou-se a resposta imune aos efeitos da aplicação de agentes clareadores tradicionalmente utilizados na clínica, assim como os de agentes reparadores utilizados no tratamento destas alterações. Inoculou-se, os agentes clareadores, perborato de sódio misturado ao peróxido de hidrogênio...

An in vitro evaluation of radicular penetration of hydrogen peroxide from bleaching agents during intra-coronal tooth bleaching with an insight of biologic response.

OBJECTIVES: External root resorption is the complication of intra-coronal bleaching done with 30% H2O2 alone or mixed with sodium perborate but not with sodium perborate mixed with water. The study was done to comparatively evaluate the H2O2 leakage from three H2O2 liberating bleaching agents. STUDY DESIGN: Fifty one single rooted human teeth were used. After root canal therapy gutta percha was removed below cemento-enamel junction. Three bleaching agents: sodium perborate mixed with water, sodium perborate mixed with 30% H2O2 and 30% H2O2 alone were used. Teeth without defect, with cervical root defect and with mid root defect constituted group A, group B and group C. According to various bleaching agents groups were subdivided into subgroup 1, 2 and 3. H2O2 leakage was measured with the help of spectrophotometer RESULTS: Almost all teeth showed H2O2 leakage. It was maximum in B1 followed by C1, B2, A1, A2, C2, B3, A3 and C3. CONCLUSION: Sodium perborate mixed with water was found to be the best bleaching agent.

Whitening the single discolored tooth.

This article discusses the possible methods available for whitening of a single discolored tooth. Treatment options can vary from restorative procedures such as crowns, veneers, or bonding to more conservative bleaching treatments. The long-term success of the treatment is dictated by proper diagnosis and treatment planning. The cause and severity of the discoloration has to be carefully evaluated when planning for bleaching options. The vitality of the pulp, presence and absence of symptoms, and periapical pathoses usually determine whether an external or internal bleaching approach will be considered.

A biocompatible model for evaluation of the responses of rat periapical tissue to a new zinc oxide-eugenol sealer.

We aimed to establish an experimental animal model to evaluate materials for endodontic therapy. We focused on the biocompatibility of new paste-type zinc oxide-eugenol (ZOE) sealer. The results of this sealer were compared with those of conventional powder/liquid ZOE and eugenol-free sealers. The molars of Wistar rats were extracted and repositioned in the original socket after application of the sealers on the root apices. Mild inflammation occurred in the periapical tissue of the replanted teeth with both ZOE sealers on day 7, whereas the eugenol-free sealer induced severe inflammation. On day 14, the lesions induced by all types of sealers were healed and replaced predominantly by fibrous connective tissue. Thus, all endodontic materials showed high biocompatibility, although the extent of inflammatory reactions during the early stages varied depending on the types of materials. We demonstrated that our animal model was useful for the assessment of the biocompatibility of endodontic materials.

Clinical and radiographic outcomes of calcium hydroxide and formocresol pulpotomies performed by dental students.

OBJECTIVE: The aim of this study was to compare the clinical and radiographic success rates of 3 pulpotomy techniques: formocresol, calcium hydroxide, and calcium hydroxide/iodoform. STUDY DESIGN: The pulpotomies were performed by fifth-year undergraduate dental students. Members of senior staff at the clinics supervised all of the procedures. Informed consent was obtained from each child's parents. The teeth were randomly assigned to the experimental (calcium hydroxide and calcium hydroxide/iodoform) or control (formocresol) groups. After coronal pulp removal and hemostasis, remaining pulp tissue was covered with calcium hydroxide or calcium hydroxide/iodoform paste in the experimental groups. In the control group, formocresol was placed with a cotton pellet over the pulp tissue for 5 minutes and removed; the pulp tissue was then covered with zinc oxide-eugenol. All teeth were restored with stainless-steel crowns. Clinical and radiographic successes and failures were recorded at 1-, 3-, 6-, and 12-month follow-ups by the authors. Data were statistically analyzed using chi-squared tests. RESULTS: The follow-up evaluations revealed that the clinical success rates were 89.7% for formocresol, 33.3% for calcium hydroxide, and 17.2% for calcium hydroxide/iodoform. The radiographic success rates were 89.7% for formocresol, 33.3% for calcium hydroxide, and 13.8% for calcium hydroxide/iodoform. CONCLUSIONS: Formocresol was superior to calcium hydroxide and calcium hydroxide/iodoform pastes for primary molar pulpotomies. Internal resorption was the most common radiographic failure in all 3 pulpotomy techniques.

Tooth whitening: concepts and controversies.

Today's society dictates that it is the norm for people to have straight, white teeth. The demand therefore for tooth whitening in dental practice has increased exponentially over the last decade. A common approach to achieving this goal is by bleaching. This article discusses clinical aspects of dental bleaching by providing an evidence-based review of current literature. Topics covered include aetiology of tooth discolouration, indications for bleaching, its mode of action, different types of bleaching regimes, indications and potential side effects.

Conservative aesthetic techniques for discoloured teeth: 1. The use of bleaching.

UNLABELLED: There is an increasing move towards more minimally invasive techniques in restorative dentistry. This series of two articles discusses conservative techniques for the treatment of discoloured teeth. A step-wise approach to treatment is promoted to encourage the most conservative solution to achieve satisfactory aesthetics. The first of these two articles will describe the use of bleaching, whilst part two will go on to describe microabrasion and the use of direct composite resin. CLINICAL RELEVANCE: Discoloured teeth are a common dental problem. Bleaching provides a simple conservative solution in many cases.

Inflammatory external root resorption following surgical treatment for intra-bony defects: a report of two cases involving Emdogain and a review of the literature.

BACKGROUND: Enamel matrix-derived proteins have been shown to regenerate periodontal tissues lost as a result of disease in humans. Emdogain, a commercial preparation of porcine enamel matrix derivative (EMD), has been shown to induce new cementum, periodontal ligament and bone formation in human periodontal defects. Although a number of studies have reported successful outcomes, local adverse effects have so far not been reported in the literature. This case report describes two examples of external inflammatory resorption following surgical root surface debridement and the use of Emdogain. TREATMENT: The treatment in both cases involved raising a full-thickness flap following completion of non-surgical therapy. The granulation tissue from the defect was removed and the root surfaces debrided. Emdogain was applied following the manufacturers' instructions and involved conditioning the root surfaces with Pref-Gel and applying the Emdogain to the defect. The flaps were sutured and the site reviewed regularly. Radiographs were taken before the treatment was undertaken and also at 6 months to assess the healing of the defect. RESULTS: External inflammatory root resorption was observed on the treated teeth 6-24 months after therapy. CONCLUSION: External inflammatory root resorption may be an unusual adverse event following Emdogain treatment.

Hydrogen peroxide tooth-whitening (bleaching) products: review of adverse effects and safety issues.

Hydrogen peroxide in the form of carbamide peroxide is widely used for tooth whitening (bleaching), both in professionally- and in self-administered products. Adverse effects have become evident. Cervical root resorption is a possible consequence of internal bleaching and is more frequently observed in teeth treated with the thermo-catalytic procedure. Tooth sensitivity is experienced in 15-78% of patients undergoing external tooth bleaching. However, clinical studies addressing other adverse effects are lacking. Direct contact with hydrogen peroxide induces genotoxic effects in bacteria and cultured epithelial cells, but the effect is reduced or totally abolished in the presence of metabolising enzymes. Several carcinogenesis studies, including the hamster cheek pouch model, indicate that hydrogen peroxide (H(2)O(2)) might possibly act as a promoter. Until further clinical research is concluded to address the question of possible carcinogenicity, it is recommended that: tooth-bleaching products using concentrated H(2)O(2) should not be used without gingival protection; that H(2)O(2) containing products should be avoided in patients with damaged or diseased soft tissues. For nightguard vital bleaching, minimal amounts of low dose H(2)O(2) (including in the form of carbamide peroxide) are preferred, thereby avoiding prolonged and concentrated exposures.

Drug-induced disorders of teeth.

It is essential that every health care professional who is involved with the prescription or recommendation of drugs be fully aware of any resultant disorders that may arise as a side-effect. A range of drugs can affect the teeth. In this review article, drugs that have the potential to induce changes in teeth have been classified as those leading to tooth discoloration (intrinsic and extrinsic), physical damage to tooth structure (enamel, dentin, and cementum), and alteration in tooth sensitivity.