External apical root resorption in retracted incisors

AIM: To evaluate the occurrence of external apical root resorption (EARR) in the incisors after anterior retraction in corrective orthodontic treatment with first premolar extractions and whether it was related with the type of root apex movement and its inclination. METHOD: The maxillary and mandibular incisors of 22 patients (12 to 25 years of age; 9 males and 13 females) were treated with fixed appliances and premolar extraction. EARR was defined as the difference in root length before and after incisal retraction on periapical radiographs. Distortion of radiographic images and changes due to incisal tipping were controlled for. Pre- and post-incisal retraction lateral cephalometric radiographs established the relationship between EARR and the tipping of the incisors, along with the vertical, horizontal, and total movement of the root apex. RESULTS: There was significant EARR (1.51 to 2.37 mm) during incisor retraction, but this was not related to the movement or the tipping of the root apex of almost all teeth. It was observed that after the retraction stage, EARR occurred in all evaluated incisors, but it was more significant (P < .05) in the mandibular right lateral incisor. CONCLUSION: The EARR that did occur was unrelated to movement or tipping of the root apex, except for the vertical root apex movement of the mandibular left central incisor and the inclination of the maxillary right lateral incisor.

Effects of coronal leakage on concentration of hydrogen ions and calcium hydroxide release of several calcium hydroxide pastes over different periods of time

Purpose: To evaluate the effects of coronal leakage on concentration of hydrogen ions (pH) and calcium release of several calcium hydroxide pastes, over different periods of time. Material and Methods: Fifty extracted human mandibular central incisors (n=10) were instrumented up to the F2 instrument and assigned to the following intracanal dressing: G1- Calen, G2- Calen with 0.4% chlorhexidine (CHX), G3- Calcium hydroxide with camphorated paramonochlorophenol (CPMC) and glycerin, G4- Calen, but temporary filling material maintained during all test (positive control) and G5- Root canal without intracanal dressing (negative control). All groups were immersed in distilled water for 7 days. In sequence, the temporary filling materials were removed, except in controls groups. All specimens were individually mounted on a specific device and only its root again immersed in distilled water. Concentration of hydrogen ions and calcium release by calcium hydroxide pastes in distilled water were evaluated in 24h, 7, 14 and 28 days. The results were submitted to ANOVA test (p = 0.05). After 28 days, root canals from experimental groups were examined in SEM. Results: G1, G2, G3 and G4 presented similar pH values and calcium release and did not differ from each other (p>0.05), up to 7 days. After this time G1, G2 and G3 presented values lower values than G4 (p<0.05). In SEM analysis, calcium hydroxide residues were observed in all experimental groups. Conclusions: After 7 days, coronal leakage decreased the concentration of hydrogen ions and calcium ion release provided by all calcium hydroxide pastes.

CLSM assessment of tubule penetration and bacterial leakage evaluation of two resin-based sealer

Aim: The aims of this study were to assess the penetration of two endodontic sealers (salicylate and epoxy resin-based sealers) into dentinal tubules using CLSM; and to evaluate the bacterial leakage of roots filled with the same sealers associated with gutta-percha. Material and Methods: For sealer penetrability assessment, thirty bovine roots were instrumented and divided into three groups: AHP: EDTA + filling with AH Plus and gutta-percha (n=10), MTAF: EDTA + filling with MTA Fillapex and gutta-percha (n=10), control group: canals were not irrigated with EDTA and were filled with gutta-percha and AH Plus (n=5) or MTA Fillapex (n=5). Rhodamine B was added to the sealers in order to provide adequate fluorescence. The roots were transversely sectioned 3mm from the apex to enable CLSM analysis. Leakage was evaluated for turbidity of the broth in a split chamber model system for 30 days, using Enterococcus faecalis as a microbial marker. Thirty roots were instrumented and divided in four grupos: AHP: filling with AH Plus and gutta-percha (n=10); MTAF: filling with MTA Fillapex and gutta-percha (n=10); positive control: filling with gutta-percha without sealer (n = 5); negative control: sealing with cyanoacrylate to test the seal of the system (n = 5). Results: The medians for dentinal tubule penetration were 6.8% (AHP) and 6.6% (MTAF) (P = 0.82). The average time for bacterial leakage was 8 days in both experimental groups (P = 0.79). Conclusion: MTA Fillapex and AH Plus presented similar behavior regarding dentinal tubule penetration and bacterial leakage.

Avaliação da capacidade de vedamento e pH do tampão apical com cimento Portland branco acrescido de radiopacificadores convencionais

The Portland cement has shown similar biological properties to calcium hydroxide, but its radiopacity is lower. Therefore, the addition of materials that minimize this deficiency should be considered. OBJECTIVE: To evaluate the apical sealing ability and pH of a white Portland cement added of several radiopacifying agents. MATERIAL AND METHODS: Forty bovine roots with incomplete apices were selected, and the foraminal openings were standardized to PM 720G bur. After the external root sealing, an apical intracanal barrier 10.0 mm thick was executed with the white Portland cement powder, pure or added of a radiopacifying agent (iodoform, zinc oxide or bismuth subnitrate), and distilled water (0.37 mL). The apical roots were immersed 24h in water in humid atmosphere, and after that they were immersed 24h in 2% Rhodamine B, under vacuum. In sequence, the roots were longitudinally sectioned, the root fragments were photographed, the images were digitalized and the apical infiltration was measured by the Image Tool program. The pH solutions were also evaluated, in 24h and 48h and 7 and 30 days. Data were submitted to Anova test. RESULTS: The zinc oxide solution has the lowest apical infiltration in relation to the other groups (p < 0.05). The pH behavior varied during the analysis, and in the period of 24h all groups showed the highest values (p < 0.05). CONCLUSION: The type of radiopacifying agent used interferes in the sealing ability of the apical barrier, and zinc oxide showed to be the most beneficial one. The pH varies according to the period of analysis, and the highest values were obtained in the first 24h (p < 0.05).

Avaliação do pH, da solubilidade e da infiltração marginal em retrobturações com o Sealer 26 puro ou acrescido de iodofórmio

Sealer 26® cement contains bisphenol epoxy resin associated with calcium hydroxide, presenting smaller radiopacity than other endodontic cements. Aiming to improve this property, iodoform has been added in its composition. However, this addition's possible changes in physical and chemical properties still need to be studied. OBJECTIVE: To evaluate the apical sealing ability, solubility, and pH of Sealer 26® alone or with iodoform, at several proportions. MATERIAL AND METHODS: Three experimental mixtures of Sealer 26®, alone or with iodoform, were prepared and subjected to solubility test. Additionally, these combinations were inserted into polyethylene tubes and immersed in distilled water, and, their pH was evaluated after 24-h and 7-day periods. Subsequently, forty roots of extracted lower incisors subdivided into four groups of 10 specimens each, were retrograde filled with one of the previously described mixtures and gutta-percha points. The roots were immersed in Rhodamine B, under vacuum, for 72 hours. After this period, the specimens were longitudinally sectioned, root fragments photographed, these images scanned, and apical infiltration measured by Image tool software. The obtained data were subjected to statistical analysis, at a significance level of 5%. RESULTS: Marginal leakage and solubility tests did not show any difference among the experimental groups (p > 0.05). pH analysis was only statistically different at 24-h period and between Sealer 26® alone and 1.1g iodoform group (p < 0.05). CONCLUSION: The presence of iodoform in Sealer 26®, at the used proportions, did not alter the solubility, apical marginal leakage and pH properties of the original cement.

Conceptos actuales en la preparación de la cavidad apical para obturación retrógrada en cirugía perirradicular

The endodontic surgery is indicated in cases of failure and/or impossibility of conventional endodontic treatment. Among the existent modalities in the endodontic surgery, the retrograde filling consists on preparation of apical cavity and filling with a retrofilling material. The technical-scientific progress in Endodontics become possible the use of retrotips activated with ultrasonic for retrocavities preparation with appropriate extension and following the long axis of the root. The aim of the study was to present the current resources in the preparation of the retrograde cavity in endodontic surgery, detaching their advantages in comparison with the use of conventional preparation with burns. A review of the literature will be presented, considering the use of ultrasound and laser for retrograde preparation, seeking the current resources that provide better apical preparation, resulting in better prognostic of the endodontic surgery (AU)

Influência do diâmetro foraminal do canal radicular, do tipo e da penetração de agulha, e do fluxo da solução irrigadora na limpeza e na extrusão apical

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Clinical Influence of Different Intracanal Medications on Th1-type and Th2-type Cytokine Responses in Apical Periodontitis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of intracanal dressings on repair and apical bridging of teeth with incomplete root formation

Periapical repair and apical bridging were studied in dog's teeth with incomplete root formation and induced chronic periapical lesions treated with different dressings. A total of 75 root canals from the upper and lower premolars of 4 dogs approximately 6 months of age were chemo-mechanically prepared and filled with the following dressings: antibacterial dressing consisting of a calcium hydroxide+camphorated p-monochlorophenol paste applied for 7 days and followed by monthly renewed calcium hydroxide paste as temporary dressing at 30, 60 and 90 days (Group A); antibacterial dressing consisting of camphorated p-monochlorophenol alone for 7 days, followed by temporary dressing with calcium hydroxide paste renewed at 30, 60 and 90 days (Group B). A control group (Group C) received no dressings. Ninety days after the last calcium hydroxide paste (Groups A, B) and after the last irrigation/aspiration (Group C), the animals were killed, the maxillae and mandibles were removed, and the material submitted to routine histological processing and examination. Both root canal dressings, were of fundamental importance for apical repair and bridging. The apical bridging was predominantly complete in Group A, incomplete in Group B, and absent in Group C. The calcium hydroxide+camphorated p-monochlorophenol combination gave better results than camphorated p-monochlorophenol alone.

Calcium hydroxide root canal sealers - Histopathologic evaluation of apical and periapical repair after endodontic treatment

Eighty root canals of the premolars of 4 dogs, with vital pulp, were instrumented and filled during the same session with the Sealapex, CRCS, Sealer 26, and Apexit sealers, the animals were sacrificed 180 days after root canal filling and their maxillae and mandibles were removed and fixed in 10% formalin, After routine histologic processing, the sections were stained with hematoxylin-eosin and Mallory trichrome, Histopathologic analysis showed that Sealapex was the sealer that best permitted the deposition of mineralized tissue at the apical level and was the only sealer that provided complete sealing (37.5% of cases), With the use of Sealapex, no inflammatory infiltrate occurred and there was no reabsorption of mineralized tissues, In contrast, partial sealing and a moderate inflammatory infiltrate occurred with the use of CRCS, When Apexit and Sealer 26 were used the absence of sealing was frequent and active reabsorption of mineralized tissues occurred in most cases, the inflammatory infiltrate predominating with the use of Apexit was of the severe type, whereas with the use of Sealer 26 the inflammatory infiltrate was mild or absent.

Correlation between volume of apical periodontitis determined by cone-beam computed tomography analysis and endotoxin levels found in primary root canal infection

This clinical study was conducted to correlate the levels of endotoxins and bacterial counts found in primary endodontic infection with the volume of periapical bone destruction determined by cone-beam computed tomography (CBCT) analysis. Moreover, the levels of bacteria and endotoxins were correlated with the development of clinical features. Twenty-four root canals with primary endodontic disease and apical periodontitis were selected. Clinical features such as pain on palpation, pain on percussion, and previous episode of pain were recorded. The volume (cubic millimeters) of periapical bone destruction was determined by CBCT analysis. Endotoxins and bacterial samplings were collected by using sterile/apyrogenic paper points. Endotoxins were quantified by using limulus amebocyte lysate assay (KQCL test), and bacterial count (colony-forming units [CFU]/mL) was determined by using anaerobic culture techniques. Data were analyzed by Pearson correlation and multiple logistic regression (P < .05). Endotoxins and bacteria were detected in 100% of the root canal samples (24 of 24), with median values of 10.92 endotoxin units (EU)/mL (1.75-128 EU/mL) and 7.5 × 10(5) CFU/mL (3.20 × 10(5)-8.16 × 10(6) CFU/mL), respectively. The median volume of bone destruction determined by CBCT analysis was 100 mm(3) (10-450 mm(3)). The multiple regression analysis revealed a positive correlation between higher levels of endotoxins present in root canal infection and larger volume of bone destruction (P < .05). Moreover, higher levels of endotoxins were also correlated with the presence of previous pain (P < .05). Our findings revealed that the levels of endotoxins found in root canal infection are related to the volume of periapical bone destruction determined by CBCT analysis. Moreover, the levels of endotoxin are related to the presence of previous pain.

Abutment coating with diamond-like-carbon films to reduce implant-abutment bacterial leakage

Backgroud: The influence of diamond-like-carbon (DLC) films on bacterial leakage through the interface between abutments and dental implants of external hexagon (EH) and internal hexagon (IH) was evaluated. Film deposition was performed by PECVD (Plasma Enhanced Chemical Vapor Deposition). Sets of implants and abutments (N=180, n=30) were divided according to the connection design and the treatment of the abutment base: (1) no treatment (control); (2) DLC film deposition, and (3) Ag-DLC film deposition. Under sterile conditions, 1 µL of Enterococcus faecalis was inoculated inside the implants, and abutments were tightened. The sets were tested for immediate external contamination, suspended in test tubes containing sterile culture broth, and followed-up for five days. Turbidity of the broth indicated bacterial leakage. At the end of the period, the abutments were removed and the internal content of the implants was collected with paper points and plated in Petri dishes. They were incubated for 24 h for bacterial viability assessment and colony-forming unit (CFU) counting. Bacterial leakage was analyzed by Chi-square and Fisher exact tests (α=5%). The percentage of bacterial leakage was 16.09% for EH implants and 80.71% for IH implants (P<0.0001). The bacterial load was higher inside these implants (P=0.000). The type of implant significantly influenced the results (P=0.000), whereas the films did not (P=0.487). We concluded that: (1) IH implants showed a higher frequency of bacterial leakage and (2) the DLC and Ag-DLC films did not significantly reduce the frequency of bacterial leakage and bacteria load inside the implants.

Efeito dos lasers de Nd:YAG e de Er:YAG na adaptação das obturações de canais radiculares: análise do selamento marginal apical

Pós-graduação em Odontologia Restauradora - ICT

Influence of irrigation and intracanal dressing on the healing process of dogs' teeth with apical periodontitis.

Dogs' teeth with apical periodontitis were treated endodontically, Dakin's solution being used in an experimental group as the irrigation solution, and camphorated paramonochlorophenol as an intracanal dressing. For a second group of teeth, the irrigation solution used was physiologic saline, dry cotton only being placed into the pulpal chamber to take the place of an intracanal dressing. In a second visit, overinstrumentation and a new application of the same kind of dressing were performed, the root canals being then filled with gutta-percha cones and zinc oxide-eugenol cement. Other specimens were treated, in one visit, where physiologic saline or Dakin's solution were the irrigation solutions. The animals were sacrificed 6 months after the obturation of the root canals. Histologic exams showed better results for the experimental group where Dakin's solution and camphorated paramonochlorophenol had been used, with signs of repair characterized by newly formed cementum and bone tissue, as well as a marked reduction in size of the periapical lesions. No differences were seen in the results with physiologic saline or Dakin's solution as irrigants.