Why not to treat the tooth canal to solve external root resorptions? Here are the principles!

ABSTRACT This paper aims at exposing the foundations or reasons why, in cases of external tooth resorption, including those of orthodontic origin, one should not perform a root canal to treat it. That should be done only to teeth with contamination or pulp necrosis, to remove the periapical inflammation induced by microbial products. When facing cases of external tooth resorption, one's conduct must always respect the following sequence of steps: first of all, identifying the cause accurately; then, planning the therapeutic approach and, finally, adopting the conducts in a very well-founded way. The situations in which endodontic treatment is recommended for tooth resorptions are those when there are: a) pulp necrosis with microbial contamination, b) aseptic pulp necrosis, c) developing calcific metamorphosis of the pulp and d) diagnosis of internal resorption. It is not possible, through the pulp, to control the resorption process that is taking place in the external part, after all, the causes are acting in the periodontal ligament. There is no evidence that justifies applying endodontic treatment, by means of root canal, to control external resorption processes, when the pulp shows vitality.

RESUMO Este artigo tem por objetivo principal expor os fundamentos ou razões pelas quais, em casos de dentes com reabsorção dentária externa, incluindo as de origem ortodôntica, não se deve fazer o canal para tratá-la. Isso se faz apenas nos dentes com contaminação ou necrose pulpar, para remover a inflamação periapical induzida pelos produtos microbianos. Frente a casos de reabsorção dentária externa, as condutas devem premiar sempre a seguinte sequência: primeiro, identificar a causa com precisão; depois, planejar a forma de abordagem terapêutica e, por fim, adotar as condutas de forma muito bem fundamentada. As situações em que o tratamento endodôntico está indicado na terapêutica das reabsorções dentárias são quando houver: a) necrose pulpar por contaminação microbiana, b) necrose pulpar asséptica, c) metamorfose cálcica da polpa inicial e d) diagnóstico de reabsorção interna. Não se consegue, por via pulpar, controlar o processo reabsortivo que está ocorrendo na parte externa; afinal, as causas estão atuando no ligamento periodontal. Não há qualquer evidência que justifique fazer o tratamento endodôntico, via canal, para controlar processos reabsortivos externos, quando a polpa está com vitalidade.

Comparison between one-session root canal treatment with aPDT and two-session treatment with calcium hydroxide-based antibacterial dressing, in dog's teeth with apical periodontitis.

To evaluate one-session endodontic treatment with aPDT and two-session treatment with calcium hydroxide (CH)-based dressing in dog's teeth with apical periodontitis. After experimental induction of apical periodontitis, 48 teeth were randomly assigned to the following groups: groups OS/aPDT120d and OS/aPDT180d (one-session treatment with aPDT) and groups TS/CH120d and TS/CH180d (two-session treatment with CH-based dressing-control groups). The animals were euthanized after 120 and 180 days. After histotechnical processing, microscopic and radiographic analyses were performed. Data were analyzed by Kruskal-Wallis and Fisher's exact tests (α = 0.05). Groups TS/CHs presented repaired resorbed cemental areas, with collagen bundles and few inflammatory cells. In groups OS/aPDTs, the areas of cemental resorption were not repaired with reduced presence of cells and fibers. In the analysis of the apical closure, fluorescence microscopy and percentage of radiographic reduction of lesions, there was significant difference between groups TS/CH120d and OS/aPDT120d and between TS/CH180d and OS/aPDT180d (p < 0.05). Groups TS/CHs had weak RANKL expression and positive immunostaining for RANK and OPG. In OS/aPDT120d, there was positive immunostaining for RANKL. In OS/aPDT180d, the three osteoclastogenesis markers were expressed. The results using aPDT were worse than those obtained with two-session endodontic treatment using a CH-based dressing in teeth with apical periodontitis.

Why not to treat the tooth canal to solve external root resorptions? Here are the principles!

This paper aims at exposing the foundations or reasons why, in cases of external tooth resorption, including those of orthodontic origin, one should not perform a root canal to treat it. That should be done only to teeth with contamination or pulp necrosis, to remove the periapical inflammation induced by microbial products. When facing cases of external tooth resorption, one's conduct must always respect the following sequence of steps: first of all, identifying the cause accurately; then, planning the therapeutic approach and, finally, adopting the conducts in a very well-founded way. The situations in which endodontic treatment is recommended for tooth resorptions are those when there are: a) pulp necrosis with microbial contamination, b) aseptic pulp necrosis, c) developing calcific metamorphosis of the pulp and d) diagnosis of internal resorption. It is not possible, through the pulp, to control the resorption process that is taking place in the external part, after all, the causes are acting in the periodontal ligament. There is no evidence that justifies applying endodontic treatment, by means of root canal, to control external resorption processes, when the pulp shows vitality.

Platelet-rich plasma derived from bone marrow aspirate promotes new cementum formation.

BACKGROUND: This study evaluates the influence of platelet-rich plasma derived from bone marrow aspirate (PRP-BMA) on the healing of periodontal fenestration defects in rats. METHODS: Periodontal fenestration defects were surgically created in the mandibles of 40 rats. The animals were randomly divided into two groups, control and PRP-BMA, in which defects were filled with blood clot or PRP-bma, respectively. Animals were euthanized at either 10 or 30 days post-surgery. Histologic, histometric, and immunohistochemical analyses were performed. Percentage of new bone area (NBA), area of bone trabeculae (ABT), new cementum (NC), and extension of remaining defect were histometrically evaluated. Proliferating cell nuclear antigen (PCNA), bone sialoprotein (BSP), osteocalcin (OCN), and tartrate-resistant acid phosphatase (TRAP) immunohistochemical staining were performed. Immunolabeled cells were quantified. Data were statistically analyzed (analysis of variance; Tukey, P <0.05). RESULTS: At 10 days, control and PRP-BMA groups presented similar amounts of NBA and ABT; NC formation was not observed. At 30 days, control and PRP-BMA groups presented similar amounts of NBA and ABT; the PRP-BMA group showed NC formation with collagen fibers inserted obliquely or perpendicularly to the root surface. NC formation was not observed in any control group specimen. PRP- BMA presented higher numbers of PCNA-positive and BSP-positive cells than control at 10 and 30 days post-surgery. No significant differences in the number of either OCN-positive or TRAP-positive cells were observed between groups at 10 or 30 days. CONCLUSION: PRP-BMA promoted NC formation with a functional periodontal ligament when applied at experimental periodontal fenestration defects.

Histologic and micro-computed tomographic analyses of replanted teeth stored in different kind of media.

INTRODUCTION: Coconut water (CW) and soy milk (SM) have been proposed as storage media for avulsed teeth because of their nutrients that preserve cell viability. The present study investigated the periodontal healing process of dog teeth replanted after storage in CW, SM, and whole milk (WM) using micro-computed tomographic (µCT) and histologic analyses compared with immediate tooth replantation. METHODS: Forty roots of 10 adult beagle dogs were extracted and subjected to the following protocols: immediate replantation after extraction (control), stored in CW with an adjusted pH, and SM and WM for 50 minutes before replantation. The animals were euthanized 28 days postoperatively, and the obtained specimens were scanned using a µCT scanner and subjected to routine processing for histometric analyses under an optical microscope. RESULTS: CW and SM performed similarly to WM; however, SM showed significantly higher ankylosis than the control group. CONCLUSIONS: Additionally, this study showed that the combined use of histologic analysis and µCT is a promising method to better identify tooth resorption and the repair process and to evaluate the total extension of the periodontium. CW as a storage medium is a promising transport media for avulsed teeth.

Force distribution is more important than its intensity!

A common question about root resorption is raised in orthodontic practice: What is more important, the intensity of force or its distribution along the root, periodontal and alveolar structures? Diffuse distribution of forces applied to periodontal tissues during tooth movement tends not to promote neither extensive areas of cell matrix hyalinization nor significant death of cementoblasts that lead to root resorption. However, focal distribution or concentration of forces within a restricted area--as it occurs in tipping movements, even with forces of lower intensity--tend to induce extensive areas of hyalinization and focal death of cementoblasts, which is commonly associated with root resorption. In tipping movements, the apical regions tend to concentrate more forces, in addition to wounding the cementoblasts due to the smaller dimension of their root structure as well as their cone shape. For this reason, there is an increase in root resorption. In the cervical region, on the other hand, the large area resulting from a large diameter and bone crown deflection tends to reduce the effects of forces, even when they are more concentrated, thus rarely inducing death of cementoblasts and root resorption.

Microscopic evaluation of induced tooth movement after subluxation trauma: an experimental study in rats.

OBJECTIVE: The objective of this study was to assess the histological alterations that occurred in the periodontal area of rat molars submitted to induced tooth movement (ITM) right after an intentional trauma (subluxation). METHODS: Forty adult male Wistar rats (Rattus norvegicus albinus) were selected. The animals were divided into eight groups (n=5), according to the combination of variables: Group 1--control (neither trauma nor ITM); Group 2--ITM; Groups 3, 4, 5 and 6--dentoalveolar trauma groups corresponding, respectively, to 1, 3, 8 and 10 days after trauma; Groups 7 and 8 - the animals' molars were subjected to a 900 cN impact and, one and three days after the trauma event, tooth movement was induced. The rats' maxillary first molars were mesially moved during seven days with a closed coil (50 cN). After the experimental period of each group, the animals were sacrificed by anesthetic overdose and the right maxillas were removed and processed for histological analysis under light microscopy. RESULTS: In the animals of group 3, 4, 5 and 6, the histological alterations were not very significant. Consequently, the effect of induced tooth movement right after a subluxation event (groups 7 and 8) was very similar to those described for Group 2. CONCLUSIONS: There was no difference in the quality of periodontal repair when ITM was applied to teeth that had suffered a subluxation trauma.

Force distribution is more important than its intensity!

A common question about root resorption is raised in orthodontic practice: What is more important, the intensity of force or its distribution along the root, periodontal and alveolar structures? Diffuse distribution of forces applied to periodontal tissues during tooth movement tends not to promote neither extensive areas of cell matrix hyalinization nor significant death of cementoblasts that lead to root resorption. However, focal distribution or concentration of forces within a restricted area - as it occurs in tipping movements, even with forces of lower intensity - tend to induce extensive areas of hyalinization and focal death of cementoblasts, which is commonly associated with root resorption. In tipping movements, the apical regions tend to concentrate more forces in addition to wounding the cementoblasts due to the smaller dimension of their root structure as well as their cone shape. For this reason, there is an increase in root resorption. In the cervical region, on the other hand, the large area resulting from a large diameter and bone crown deflection tends to reduce the effects of forces, even when they are more concentrated, thus rarely inducing death of cementoblasts and root resorption.

Um questionamento comum sobre as reabsorções radiculares na prática ortodôntica: "O que é mais importante? A intensidade das forças aplicadas ou sua distribuição ao longo das estruturas radiculares, periodontais e alveolares?" A distribuição difusa das forças aplicadas sobre os tecidos periodontais durante o movimento dentário de corpo tende a não promover extensas áreas de hialinização da matriz extracelular, nem morte significativa de cementoblastos que levariam à reabsorção radicular. Porém, a distribuição focal ou concentração de forças - como nas inclinações, mesmo nas de menor intensidade - em uma área restrita tende a induzir áreas extensas de hialinização e morte focal de cementoblastos, associando-se mais comumente à reabsorção radicular. Nos movimentos de inclinação, as áreas apicais, por sua menor dimensão da estrutura radicular e sua forma cônica, tendem a concentrar mais ainda as forças e lesar cementoblastos, aumentando a frequência das reabsorções radiculares. Na região cervical, a maior área decorrente do maior diâmetro e a deflexão óssea da crista óssea tendem a reduzir os efeitos das forças, mesmo quando mais concentradas, muito raramente induzindo a morte de cementoblastos e reabsorções radiculares.

Microscopic evaluation of induced tooth movement after subluxation trauma: an experimental study in rats

OBJECTIVE: The objective of this study was to assess the histological alterations that occurred in the periodontal area of rat molars submitted to induced tooth movement (ITM) right after an intentional trauma (subluxation). METHODS: Forty adult male Wistar rats (Rattus norvegicus albinus) were selected. The animals were divided into eight groups (n = 5), according to the combination of variables: Group 1 - control (neither trauma nor ITM); Group 2 - ITM; Groups 3, 4, 5 and 6 - dentoalveolar trauma groups corresponding, respectively, to 1, 3, 8 and 10 days after trauma; Groups 7 and 8 - the animals' molars were subjected to a 900 cN impact and, one and three days after the trauma event, tooth movement was induced. The rats' maxillary first molars were mesially moved during seven days with a closed coil (50 cN). After the experimental period of each group, the animals were sacrificed by anesthetic overdose and the right maxillas were removed and processed for histological analysis under light microscopy. RESULTS: In the animals of group 3, 4, 5 and 6, the histological alterations were not very significant. Consequently, the effect of induced tooth movement right after a subluxation event (groups 7 and 8) was very similar to those described for Group 2. CONCLUSION: There was no difference in the quality of periodontal repair when ITM was applied to teeth that had suffered a subluxation trauma. .

OBJETIVO: avaliar as alterações histológicas ocorridas na área periodontal de molares de ratos submetidos à movimentação dentária induzida (MDI), logo após um trauma intencional (subluxação). MÉTODOS: quarenta ratos Wistar machos adultos (Rattus norvegicus albinus) foram selecionados. Os animais foram divididos em oito grupos (n = 5), de acordo com a combinação das variáveis: Grupo 1 - controle (sem trauma e sem MDI); Grupo 2 - MDI; Grupos 3, 4, 5 e 6 - grupos de trauma dentoalveolar correspondendo, respectivamente, para 1, 3, 8 e 10 dias após o trauma; Grupos 7 e 8 - os molares murinos foram submetidos a um impacto de 900cN e, de um e três dias após o evento trauma, o movimento do dente foi induzido. Os primeiros molares superiores dos animais foram movidos mesialmente durante sete dias, com uma mola fechada (50cN). Após período experimental de cada grupo, os animais foram sacrificados por overdose anestésica e as maxilas direitas foram removidas e processadas para análise histológica qualitativa. RESULTADOS: nos animais dos grupos 3, 4, 5 e 6, as alterações histológicas não foram muito significativas. Consequentemente, o efeito do movimento dentário induzido logo após um evento de subluxação (grupos 7 e 8) foi muito semelhante ao descrito para o grupo 2. CONCLUSÃO: não houve diferença na qualidade do reparo periodontal quando a MDI foi aplicada aos dentes que sofreram um trauma de subluxação. .

Platelet-rich plasma, low-level laser therapy, or their combination promotes periodontal regeneration in fenestration defects: a preliminary in vivo study.

BACKGROUND: This study histomorphometrically analyzes the influence of platelet-rich plasma (PRP), low-level laser therapy (LLLT), or their combination on the healing of periodontal fenestration defects (PFDs) in rats. METHODS: PFDs were surgically created in the mandibles of 80 rats. The animals were randomly divided into four groups: 1) C (control) and 2) PRP, defects were filled with blood clot or PRP, respectively; 3) LLLT and 4) PRP/LLLT, defects received laser irradiation, were filled with blood clot or PRP, respectively, and then irradiated again. Animals were euthanized at either 10 or 30 days post-surgery. Percentage of new bone (NB), density of newly formed bone (DNB), new cementum (NC), and extension of remaining defect (ERD) were histomorphometrically evaluated. Data were statistically analyzed (analysis of variance; Tukey test, P <0.05). RESULTS: At 10 days, group PRP presented ERD significantly lower than group C. At 30 days, group PRP presented NB and DNB significantly greater than group C. Groups LLLT, PRP, and PRP/LLLT showed significant NC formation at 30 days, with collagen fibers inserted obliquely or perpendicularly to the root surface. NC formation was not observed in any group C specimen. CONCLUSIONS: LLLT, PRP, or their combination all promoted NC formation with a functional periodontal ligament. The combination PRP/LLLT did not show additional positive effects compared to the use of either therapy alone.

Intermittent parathyroid hormone administration improves periodontal healing in rats.

BACKGROUND: Intermittent administration of parathyroid hormone (PTH) promotes new bone formation in patients with osteoporosis and bone fractures. It was shown previously that PTH also reduces periodontitis-related bone loss. The aim of this study is to evaluate the effect of treatment with PTH on periodontal healing in rats. METHODS: Fenestration defects were created at the buccal surface of the distal root of the mandibular first molars, and both periodontal ligament (PDL) and cementum were removed. Animals were then assigned to two groups (eight animals per group): group 1: control, placebo administration; and group 2: test, human PTH (hPTH) 1-34 administration at a concentration of 40 µg/kg. For both groups, the animals were injected every 2 days, and the animals were sacrificed at 14 and 21 days after surgery. Specimens were harvested and processed for routine decalcified histologic sections. The following parameters were assessed: 1) remaining bone defect extension (RBDE); 2) newly formed bone density (NFBD); 3) total callus area (TCA); 4) osteoclast number (ON) in the callus region; and 5) newly formed dental cementum-like tissue (NFC). Birefringence of root PDL reattachment was also evaluated. RESULTS: Birefringence analysis showed root PDL reattachment for both groups 21 days after treatment. Intermittent hPTH 1-34 administration decreased RBDE (P <0.01) and increased NFBD (P <0.01), TCA (P <0.01), area of NFC (P <0.01), and ON in the callus region (P <0.01). CONCLUSION: Within the limits of the present study, intermittent administration of hPTH 1-34 led to an enhanced periodontal healing process compared with non-treated animals.

Comparison of microleakage of different margin types around Class V resin restorations in primary teeth.

AIM: This in vitro study compared the effect of a concave with a straight-bevelled cavity margin on the microleakage of Class V composite resin restorations in primary teeth. MATERIALS AND METHODS: Standardised Class V cavity preparations were made in vitro on the buccal (all margins placed in enamel) and on the lingual (margins placed in enamel and cementum) surfaces of 20 sound primary molars. The teeth were randomly assigned to two groups of 10 each: in Group 1, a concave bevel was made with a high-speed No. 04 tungsten carbide bur and in Group 2, a straight bevel was made with a high-speed No. 556 tungsten carbide bur. The teeth were restored incrementally with Adper Single Bond 2 (3M) adhesive and Filtek Z 350 (3M) composite resin. All specimens were subsequently thermocycled and immersed in 50% silver nitrate solution. Microleakage of the restorations was then assessed by silver penetration. A grading scale of 0 to 4 was used as the scoring criterion. RESULTS: At the enamel margins no statistically significant differences were observed between the two groups (p>>0.05). Occlusal walls in enamel, in both groups, exhibited less leakage than the cervical walls in cementum (p<0.01) and Group 1 showed better results than Group 2 in decreasing microleakage at the cementum margins (p <0.05). CONCLUSION: Based on the results, it was concluded that concave-beveled cavity preparations may reduce but did not totally eliminate microleakage at the cementum margins of Class V composite resin restorations in primary teeth.

The four mechanisms of dental resorption initiation.

The aim of this study is to present a classification with a clinical application for root resorption, so that diagnosis will be more objective and immediately linked to the source of the problem, leading the clinician to automatically develop the likely treatment plan with a precise prognosis. With this purpose, we suggest putting together all diagnosed dental resorptions into one of these four criteria: 1) Root resorption caused by cementoblast cell death, with preservation of the Malassez epithelial rests. 2) Root resorption by cementoblasts and Malassez epithelial rests death. 3) Dental resorption by odontoblasts cell death with preservation of pulp vitality. 4) Dental resorption by direct exposure of dentin to gingival connective tissue at the cementoenamel junction gaps.

Effects of medications and laser on induced tooth movement and associated root resorption: four key points.

The following four fundamental points on the use of experimental models will be described to ensure an accurate evaluation of the effects of medication and laser therapy on induced tooth movement and associated root resorption: (1) If the objective is to check the effect on root resorption, the forces experimentally applied must produce a lesion on the cementoblast layer in all specimens; (2) If the objective is to optimize induced tooth movement and reduce treatment time without side effects, the forces experimentally applied should not produce a lesion in the cementoblast layer in any specimen; (3) The laser therapy operator, the person administering medication and the person that places appliances should not know which animals will effectively receive the test treatment, and the control groups should receive placebo treatments; (4) CT and microscopic analysis of the specimens should be random, and the group to which the specimen belongs should not be identified, to ensure that the person reading images and the pathologists are not influenced in their evaluation of phenomena. These measures will ensure that results are more reliable and easier to extrapolate to orthodontic clinical practice.

The four mechanisms of dental resorption initiation

The aim of this study is to present a classification with a clinical application for root resorption, so that diagnosis will be more objective and immediately linked to the source of the problem, leading the clinician to automatically develop the likely treatment plan with a precise prognosis. With this purpose, we suggest putting together all diagnosed dental resorptions into one of these four criteria: 1) Root resorption caused by cementoblast cell death, with preservation of the Malassez epithelial rests. 2) Root resorption by cementoblasts and Malassez epithelial rests death. 3) Dental resorption by odontoblasts cell death with preservation of pulp vitality. 4) Dental resorption by direct exposure of dentin to gingival connective tissue at the cementoenamel junction gaps.

O presente trabalho propõe-se a apresentar uma classificação, com aplicação clínica, para as reabsorções dentárias, para que o diagnóstico seja objetivo e imediatamente ligado à causa do problema, levando automaticamente o clínico ao provável plano de tratamento e a um prognóstico preciso. Com esse objetivo, sugerimos agrupar cada caso clínico de reabsorção dentária em um dos seguintes grupos: 1) Reabsorções radiculares pela morte dos cementoblastos, com manutenção dos restos epiteliais de Malassez. 2) Reabsorções radiculares pela morte dos cementoblastos e dos restos epiteliais de Malassez. 3) Reabsorções dentárias pela morte dos odontoblastos, com manutenção da vitalidade pulpar. 4) Reabsorções dentárias pela exposição direta da dentina ao tecido conjuntivo gengival, nos gaps da junção amelocementária.

Histological findings of revascularized/revitalized immature permanent molar with apical periodontitis using platelet-rich plasma.

INTRODUCTION: An immature mandibular right first molar (#30) with apical periodontitis of a 9-year-old boy was treated with a revascularization/revitalization procedure using either a mixture of platelet-rich plasma (PRP) and a blood clot or a blood clot alone on the same tooth. METHODS: Tooth #30 fractured 2 years and 1 month after the revascularization/revitalization procedure and could not be saved. The tooth was extracted and processed for histologic examination to determine the nature of the tissues that formed in the canals. RESULTS: Clinically, the endodontic treatment of the case was successful based on the resolution of apical periodontitis and the absence of clinical signs and symptoms. Histologically, the tissues formed in the distal and mesial canals were mineralized tissue similar to cementoid/osteoid tissue and uninflamed fibrous connective tissue regardless of PRP or no PRP treatment. No pulp-like tissue characterized by the presence of odontoblast-like cells polarized along the dentin-like mineralized tissue was observed. CONCLUSIONS: The tissues formed in the canals were mineralized tissue and some fibrous connective tissue. No pulp-like tissue characterized by the presence of odontoblast-like cells was observed lining the dentin-like mineralized tissue.

Evaluation of the anti-resorptive ability of an experimental acetazolamide paste for the treatment of late replanted teeth: a study in rats.

When late replantation is performed, the root surface and root canal should be treated. Notwithstanding failures still occur, because of the high rates of root resorption, evidencing the need to search for substances that may inhibit root resorption. The acetazolamide is a known anti-resorptive agent, and its use as root canal dressing may increase the success rates in the treatment of root resorption. Therefore, this study evaluated the effect of an acetazolamide paste used as root canal dressing in late replanted teeth. The study was conducted on 24 maxillary right incisors of rats, which were avulsed and divided in two groups. In group I, the teeth were kept dry for 30 min, had their root surfaces rubbed with a blade, and were treated with 2% sodium fluoride at pH 5.5 for 20 min; the root canals were instrumented and filled with acetazolamide paste; and then the teeth were replanted. In group II, the treatment was similar to group I, except for the root canal dressing, with utilization of calcium hydroxide in group II. At 15 and 60 days after replantation, the animals were killed and the specimens were processed in a histotechnical laboratory for microscopic and morphometric analysis. The results demonstrated the ability of both intracanal substances to limit root resorption, yet they were unable to completely inhibit the root resorption. Replacement resorption lacunae were present in greater proportion in group II, at 60 days. It was concluded that the acetazolamide paste was effective to limit the root resorption, being more effective in limiting the replacement resorption compared with calcium hydroxide.

Cementoblastoma: a case report in deciduous tooth.

BACKGROUND: The benign cementoblastoma is an odontogenic tumor originated from neoplastic cementoblasts, a rare lesion mainly associated to impacted and deciduous teeth. It affects mostly young people with an average age of 20 years old, and its preferred location is in the posterior region of the mandible; the lesion will present itself fused both radiologically and microscopically to a root of an erupted permanent tooth, and the anatomopathological diagnosis is obtained through the analysis of the piece sent together with the involved dental element. CASE REPORT: The present study presents a case of cementoblastoma in the mandible involving the second deciduous molar tooth and preventing the eruption of the premolar tooth in a girl aged 11 years old. DISCUSSION: This report discusses relevant aspects concerning clinical, radiographic, and histopathological characteristics and treatments.

Histometric analysis of the effect of enamel matrix derivative on the healing of periodontal defects in rats with diabetes.

BACKGROUND: Diabetes mellitus (DM) involves metabolic changes that can negatively influence periodontal tissues, resulting in impaired periodontal repair. There is a lack of information about the outcomes of regenerative approaches under the influence of DM. Enamel matrix derivatives (EMDs) have been used in periodontal regenerative procedures, resulting in improvement of clinical parameters. Thus, the aim of this histomorphometric study is to evaluate the healing of periodontal defects after treatment with EMD under the influence of DM. METHODS: Twenty Wistar rats were randomly assigned to two groups: group 1 (G1): DM was induced with a single intraperitoneal injection of streptozotocin (STZ) (n = 10); group 2 (G2): rats were not exposed to STZ (n = 10). Seven days after DM induction, bilateral fenestration defects were created at the buccal aspect of the first mandibular molar. After the surgeries, the defects of each animal were randomly assigned to two subgroups: non-treated (control) and treated with EMD. The animals were euthanized 21 days later, and the percentage of defect fill (DF), newly formed bone density (BD), and new cementum formation (NCF) were histometrically assessed. The number of osteoclasts was determined by tartrate-resistant acid phosphatase. Weight and blood glucose were also analyzed. Mann-Whitney U test was used for comparison among groups and Wilcoxon test for comparison between the start and end times (weight and blood glucose) and between treatments (NCF and number of osteoclasts). One-way analysis of variance was used to assess DF and BD. Tukey test was used when the analysis of variance test detected significant differences (α = 5%). RESULTS: G1 (DM) showed less DF and BD compared with G2. EMD provided an increased DF in both groups and enhanced BD and NCF only in G2. The number of TRAP-positive osteoclasts was significantly higher in EMD-treated sites of G1. CONCLUSIONS: DM may produce a significant detrimental effect on BD. EMD may provide greater DF under diabetic or normal conditions; however, it may not significantly increase NCF in animals with DM.

Uso de trióxido mineral agregado (MTA) en el tratamiento de una reabsorción cemento-dentinaria externa: caso clínico / The use of mineral trioxide aggregate (MTA) in external root resorption treatment: a clinical case

Objetivos: se describe el tratamiento de una pieza dentaria que presenta reabsorción cemento-dentinaria externa (RCDE) como consecuencia de un traumatismo ocurrido hace veinticinco años. Caso clínico: la resolución se completó en dos etapas. En la primera, dado que se observó una obturación incorrecta, se realizó el retratamiento endodóntico y se obturó con conos de gutapercha y sellador Sealer 26. En la sesión siguiente, se levantó un colgajo con el objetivo de exponer y explorar la zona radiolúcida presente en distal de la raíz a la altura del tercio medio. Se realizó un curetaje y se rellenó la cavidad de la reabsorción con trióxido mineral blanco (MTA). La rehabilitación estética de la corona fue realizada con una carilla de composite a mano alzada. Después de dos años de haber realizado el tratamiento y en controles radiográficos periódicos, se observó que la RCDE se detuvo. Conclusión: las reabsorciones cemento-dentinarias externas inflamatorias son lesiones relativamente frecuentes luego de un traumatismo dentario. Es importante realizar un diagnóstico temprano para evitar su evolución y la consecuente pérdida de la pieza. El material fue elegido teniendo en cuenta sus propiedades físicas y químicas, entre las que se destacan su baja citotoxicidad, la capacidad de solidificar en presencia de humedad y el estímulo que ejerce sobre la regeneración del ligamento periodontal.