Pulp canal obliteration after traumatic injuries in permanent teeth - scientific fact or fiction?

Abstract: Pulp canal obliteration (PCO) is a frequent finding associated with pulpal revascularization after luxation injuries of young permanent teeth. The underlying mechanisms of PCO are still unclear, and no experimental scientific evidence is available, except the results of a single histopathological study. The lack of sound knowledge concerning this process gives rise to controversies, including the most suitable denomination. More than a mere semantic question, the denomination is an important issue, because it reflects the nature of this process, and directly impacts the treatment plan decision. The hypothesis that accelerated dentin deposition is related to the loss of neural control over odontoblastic secretory activity is well accepted, but demands further supportive studies. PCO is seen radiographically as a rapid narrowing of pulp canal space, whereas common clinical features are yellow crown discoloration and a lower or non-response to sensibility tests. Late development of pulp necrosis and periapical disease are rare complications after PCO, rendering prophylactic endodontic intervention useless. Indeed, yellowish or gray crown discoloration may pose a challenge to clinicians, and may demand endodontic intervention to help restore aesthetics. This literature review was conducted to discuss currently available information concerning PCO after traumatic dental injuries (TDI), and was gathered according to three topics: I) physiopathology of PCO after TDI; II) frequency and predictors of pulpal healing induced by PCO; and III) clinical findings related to PCO. Review articles, original studies and case reports were included aiming to support clinical decisions during the follow-up of teeth with PCO, and highlight future research strategies.

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. .

Microbiological and microscopic analysis of the pulp of non-vital traumatized teeth with intact crowns

OBJECTIVE: This study evaluated the presence of microorganisms and analyzed microscopically the pulp of 20 traumatized human teeth with intact crowns and clinical diagnosis of pulp necrosis, based on the association of at least three of the clinical criteria: crown discoloration, negative response to thermal and electric pulp vitality tests, positive response to vertical and horizontal percussion, pain on palpation or mobility. MATERIAL AND METHODS: Microbiological collection was performed from the root canals to evaluate the presence of microorganisms. The pulp samples were stained with hematoxylin and eosin (H.E.) for histological evaluation of possible morphological alterations. RESULTS: Analysis of results was performed by statistical tests (linear regression test and diagnostic analysis) and subjective analysis of the sections stained with H.E. and revealed that only 15 percent of the sample did not exhibit microbial development. The time elapsed between dental trauma and onset of endodontic intervention ranged from 15 days to 31 months; the percussion test presented high sensitivity (80 percent) for detection of microorganisms in the root canal of traumatized teeth; 3 teeth (15 percent) did not present pulp tissue, being characterized as complete autolysis; analysis of pulp samples was performed on the other 17 cases, among which 3 (15 percent) exhibited partial necrosis without possibility of repair and 14 presented complete necrosis; none of the clinical criteria employed for the diagnosis of pulp necrosis in traumatized teeth was pathognomonic. CONCLUSIONS: The present results allowed the following conclusions: with regard to microbiological findings, 85 percent of teeth presented microorganisms in the root canal, despite the presence of an intact crown. Concerning the microscopic findings, 100 percent of traumatized teeth presented pulp necrosis; the pulp vitality tests based on pulp response to heat, cold and vertical percussion ...