The impact of rapid maxillary expansion on maxillary first molar root morphology of cleft subjects.

OBJECTIVES: The aim of this prospective cohort study was to determine the effects of rapid maxillary expansion (RME) on the first molar roots of cleft lip and palate subjects along different root development stages. MATERIALS AND METHODS: Thirty participants with unilateral cleft lip and palate were divided into three groups (n = 10), according to the type of expander used: Hyrax, iMini and Fan-type. A cone beam CT scan was performed before (T1) and 3 months after stabilization of the appliance (T2). Measurements of root lengths of the first permanent maxillary molars were taken to evaluate root development and external apical root resorption (EARR). RESULTS: Roots presenting open apexes before treatment exhibited a statistically significant increase in root length after treatment (P < .001). Conversely, there were no significant changes in the root length of roots that had closed apexes at the beginning of treatment (P > .05). Furthermore, there were no differences among groups, or correlation between cleft side and gender was found vis-à-vis to changes in the root length (p > .05). CONCLUSIONS: Orthopaedic forces of RME were neither able to interrupt the root development process nor to cause EARR in cleft subjects. CLINICAL RELEVANCE: As the RME is the most common orthodontic procedure in patients with cleft lip and palate, understanding its impact on dental structures is of fundamental importance.

Measurement of open apices in tooth roots in Colombian children as a tool for human identification in asylum and criminal proceedings.

Dental age estimation was recognized as an imperative issue in clinical and medico-legal practice. However, very few studies on dental age estimation in children have been published in Colombia. This study evaluated the accuracy of Cameriere's method of measurement of open apices on tooth roots in a sample of 526 digital panoramic radiographs (OPTs) of children (274 boys and 252 girls), aged between 6 and 14 years, from Bogotá, Valle del Cauca, Buga and Villavicencio, in Southwest Colombia. Only first seven permanent lower teeth, except third molar, from the left side of mandible were studied. Difference between dental age and chronological age was evaluated for boys and girls across nine age classes. Intra-class correlation coefficient and Kappa score was used to test intra- and inter-observer agreement error rate. Dental age was overestimated by 0.08 years and standard deviation (±SD) of 0.68 years in boys which was not statistically significant (p = 0.06), while in girls dental age underestimated by -0.25 ± 0.65 years which was statistically significant difference (p < 0.001). The absolute difference between DA and CA or mean prediction error (ME) was 0.57 ± 0.38 years in boys and 0.57 ± 0.41 in girls (p = 0.966) which implies that Cameriere's European formula is similarly accurate in both sexes in this sample of Colombian children.

Uncommon disturbance of root development after tooth replantation: five-year follow-up period case report / Trastorno del desarrollo radicular poco frecuente posterior a reimplante dentario: reporte de caso con 5 años de seguimiento

To present an uncommon disturbance of root development with ingrowth of bone and periodontal tissue into the pulp space in a delayed replanted immature permanent incisor at five years of follow-up. Severe arrest of root formation with uncommon healing of an immature permanent maxillary incisor after delayed replantation is reported. Continued development of a tooth root separate from the body of the tooth was not observed. A 6-year-old girl sustained an avulsion injury to her upper left central permanent incisor. The tooth was replanted and splinted 2 hours after the accident. Patient has been monitored clinically and with radiography for 5 years. The periodontal tissues presented good healing without replacement resorption. However, severe arrest of root formation with development of hard-like tissue and internal periodontal ligament inside the pulp canal have been observed. Despite being a delayed tooth replantation, the patient has been asymptomatic, and has maintained alveolar bone volume. Clinicians must be vigilant and monitor traumatized immature teeth closely.

El objetivo de este trabajo fue presentar una alteración poco frecuente del desarrollo de la raíz con el crecimiento del tejido óseo y periodontal en el espacio pulpar en un incisivo permanente inmaduro reimplantado de manera tardía, a los cinco años de seguimiento.Se observó una suspensión severa de la formación de raíces con cicatrización poco común, de un incisivo maxilar permanente inmaduro después de una reimplantación tardía. No se observó el desarrollo continuo de la raíz dentaria separada del diente. Una niña de 6 años de edad sufrió una lesión por avulsión en su incisivo central superior izquierdo. El diente fue replantado dos horas después del accidente. La paciente ha sido monitoreada clínicamente y con exámenes radiológicos durante 5 años. Los tejidos periodontales presentaron buena cicatrización sin reabsorción de reemplazo. Sin embargo, se ha observado una detención severa de la formación de las raíces, con desarrollo de tejido duro y ligamento periodontal interno dentro del canal pulpar. A pesar de ser una reimplantación tardía del diente, la paciente presenta asintomática, y ha mantenido el volumen del hueso alveolar. Los médicos deben estar atentos y mantener en observación los dientes inmaduros traumatizados.

Autogenous premolar transplantation into artificial socket in maxillary lateral incisor site.

INTRODUCTION: Autogenous transplantation of a natural tooth to another site has significant advantages over dental implants, particularly in cases of agenesis, accidental tooth loss, or poor prognosis for the maintenance of tooth function. METHODS: This report describes a case of autogenous premolar transplantation into an artificial socket in the site of a missing maxillary lateral incisor in a 13-year-old girl. Clinical examination and radiography revealed tooth agenesis (#4, #10, #13, and #20) and microdontia (#7). The occlusion and skeletal maxillomandibular relations were normal. RESULTS: Tooth #29 was chosen for transplantation into the site of tooth #10 because of its size, stage of root formation, and possible closure of the spaces created by agenesis. CONCLUSIONS: Autogenous transplantation is a feasible alternative to dental implants in cases of tooth agenesis or tooth loss because of trauma. Autotransplantation was indicated in this case because it ensures the natural (facial) growth of the alveolar process and preserves the function of periodontal tissues. A multidisciplinary approach (ie, combining techniques from different dental specialties) was important for treatment success. Clinical and radiographic follow-up confirmed that the transplanted premolar was esthetically comparable with the lateral incisor and that root development and pulp canal obliteration were complete.

Intracanal delivery of Resolvin E1 controls inflammation in necrotic immature rat teeth.

INTRODUCTION: Pulp necrosis in immature teeth and the resulting periodontal apical inflammation negatively affect root formation. Resolvin E1 (RvE1) is a lipid-derived endogenous pro-resolution molecule that controls inflammation. The aim of this investigation was to evaluate the impact of RvE1 applied as an intracanal medication on root formation in nonvital immature teeth. METHODS: To arrest root development, pulpectomy was performed in the lower first molars of 4-week-old Wistar rats. After 3 weeks, irrigation with 2.5% sodium hypochlorite and 0.9% sterile saline was performed, and either a triple antibiotic paste (TAP) or RvE1 in saline was applied into the root canals. In the control group, access openings drilled into molars were left exposed to the oral environment. Root development and periapical repair were evaluated radiographically and histologically at 3 and 6 weeks after treatment. RESULTS: RvE1 reduced periapical lesion size compared with the control at 3 weeks, which was similar to TAP. Inflammatory response in the RvE1-treated group was markedly reduced compared with both TAP and control specimens. At 6 weeks, root development was observed in both groups, but RvE1 treatment produced less cellularity with more regular calcified tissue deposition. CONCLUSIONS: RvE1 and TAP had a positive impact on reducing inflammation and promoting root formation. RvE1 was more effective in reducing inflammation at earlier stages. RvE1 has potential to be used as root canal dressing to control inflammation in endodontically compromised teeth before complete root formation. Stability of RvE1 within the root canal and its delivery are issues to be addressed before its clinical use.

Immunolocalization of Smad-4 in developing molar roots of alendronate-treated rats.

INTRODUCTION: During root formation, Smad-4 plays a key role during the epithelial-mesenchymal interactions and the Hertwig's epithelial root sheath (HERS) apical proliferation. The root formation and eruption of rat molars is impeded by alendronate treatment due to the inhibition of bone resortion by this drug. The present study aimed to examine the structures affected in the developing root and immunodetect the presence of Smad-4 in rats treated with alendronate. METHODS: Newborn Wistar rats were daily injected 2.5 mg/kg alendronate (ALN) during 9, 12 and 30 days. The controls (CON) were injected with saline. The maxillae were fixed and embedded in paraffin or Spurr resin. Paraffin sections were incubated in Smad-4 antibody that was labelled with DAB. The ultrathin sections were examined in a transmission electron microscope. RESULTS: In ALN, a short portion of root dentine was formed; the epithelial diaphragm (ED) and the dental follicle (DF) were disorganized by the contact of bone trabeculae. The (CON) molar roots developed normally. Smad-4 labelling was detected in the cytoplasm of fibroblasts and cementoblasts adjacent to the cementum in CON; in ALN group, few ED cells presented weak immunolabelling. Ultrastructurally, the ED and DF appeared disrupted due to the presence of thin bone trabeculae between its cells. It resulted in the lack of apical proliferation of HERS and, consequently, arrest of root formation. CONCLUSION: The immunodetection of Smad-4 in the DF cells of ALN specimens indicates that the signalling for the differentiation of these cells into cementum-forming fibroblasts and cementoblasts occurs, despite the impairment of root elongation.

[In vitro evaluation of fracture resistance of teeth with incomplete root development and intracanal reinforcement with different materials]. / Evaluación in vitro de la resistencia a la fractura en dientes con desarrollo radicular incompleto reforzados intraconducto con diferentes materiales.

The aim of this study was to evaluate the fracture resistance of teeth with incomplete root development and intracanal reinforcement with adhesives materials. 50 human central and lateral incisors were instrumented and prepared to simulate an immature tooth and filled apically with MTA. The samples were divided into four experimental groups and one control group. Group 1: resin composite Filtek P90; Group 2: glass Ionomer Vitremer; Group 3: resin composite Filtek Z350 XT; Group 4: glass Ionomer Ketac N 100; Group 5: negative control (instrumented but not reinforced). After, the fracture test was performed using a fracture universal testing machine (Instron). The maximum values of resistance before catastrophic fracture were collected and analyzed by Anova (p = 0.05). The results show a significant difference between the groups compared (p = 0.02). A significant difference was found between group 1 (847.73 N) and group 5 (474.77 N) (p = 0.02) applying the Bonferroni test. Despite the limitations of the study, the conclusion is that micro-hybrid composite resins are ideal materials to strengthen teeth with incomplete root development endodontically treated.

Evaluación in vitro de la resistencia a la fractura en dientes con desarrollo radicular incompleto reforzados intraconducto con diferentes materiales / In vitro evaluation of fracture resistance of teeth with incomplete root development and intracanal reinforcement with different materials

El objetivo de este trabajo fue evaluar la resistencia a la fractura de dientes con desarrollo radicular incompleto y refuerzo intrarradicular con materiales adhesivos. 50 dientes incisivos centrales y laterales maxilares humanos fueron instrumentados y preparados intraconducto para simular un diente inmaduro y obturado apicalmente con MTA. Las muestras fueron divididas en cuatro grupos experimentales y un grupo control. Grupo 1: Resina compuesta Filtek™ P90; Grupo 2: Ionómero de vidrio Vitremer™; Grupo 3: Resina compuesta Filtek™ Z350 XT; Grupo 4: Ionómero de vidrio Ketac™ N 100; Grupo 5: Control negativo (Instrumentado pero no se reforzó intraconducto). Luego se realizó la prueba de fractura utilizando una maquina de ensayo universal (Instron™). Los valores máximos de resistencia antes de la fractura catastrófica fueron recolectados y analizados mediante la prueba Anova (p = 0,05). Como resultado se encontró diferencia significativa entre los grupos comparados (p = 0,02). Fue encontrada diferencia significativa entre los grupos 1 (847,73N) y el grupo 5 (474,77N) (p = 0,02) aplicando el test de Bonferroni. Pese a las limitaciones del estudio se puede concluir que las resinas compuestas microhíbridas se muestran como un material óptimo para reforzar intrarradicularmente dientes con desarrollo radicular incompleto tratados endodónticamente.

The aim of this study was to evaluate the fracture resistance of teeth with incomplete root development and intracanal reinforcement with adhesives materials. 50 human central and lateral incisors were instrumented and prepared to simulate an immature tooth and filled apically with MTA. The samples were divided into four experimental groups and one control group. Group 1: resin composite Filtek™ P90; Group 2: glass Ionomer Vitremer™; Group 3: resin composite Filtek™ Z350 XT; Group 4: glass Ionomer Ketac™ N 100; Group 5: negative control (instrumented but not reinforced). After, the fracture test was performed using a fracture universal testing machine (Instron™). The maximum values of resistance before catastrophic fracture were collected and analyzed by Anova (p = 0.05). The results show a significant difference between the groups compared (p = 0.02). A significant difference was found between group 1 (847.73 N) and group 5 (474.77 N) (p = 0.02) applying the Bonferroni test. Despite the limitations of the study, the conclusion is that micro-hybrid composite resins are ideal materials to strengthen teeth with incomplete root development endodontically treated.

Autotransplantation of a premolar: a long-term follow-up report of a clinical case.

INTRODUCTION: This report describes the clinical management of a case in which a maxillary central incisor was lost after a traumatic injury. METHODS: A mandibular premolar with incomplete root development was transplanted into the alveolar socket of the lost central incisor. RESULTS: The case evolved favorably for 12 years, remaining vital to pulp sensitivity tests and developing a favorable crown-root ratio even after it was orthodontically moved. CONCLUSIONS: Premolar autotransplantation should be considered an important and valid biological alternative in cases of premature tooth loss both in young patients and adults in order to avoid or delay implant placement or other type of restoration.

Dilaceración de diente primario asociado a un mesiodens en niño de 4 años / Dilaceration temporary tooth associated with a mesidens in 4 year old

Dilaceración es un término utilizado para describir la distorsión que ocurre en la raíz durante el desarrollo dentario, el cual se manifiesta alterando la normal relación axial entre la corona y la raíz dentaria. La dilaceración radicular es una angulación o curvatura de la raíz dentaria. Esta alteración es frecuentemente observada en dientes permanentes como consecuencia de un traumatismo de su correspondiente temporario, con una incidencia de 3 %. En la literatura hay solamente cinco casos de dilaceración que involucran a incisivos temporarios. El propósito de este artículo fue hacer una revisión y presentar un caso clínico que fue un hallazgo radiográfico

Dilaceration is a term used to describe the distortion that occurs in the root during tooth development, which manifests itself by altering the normal axial relationship between the crown and the dental root. The root is dilaceration, angulation or curvature of the tooth root. This alteration is frequently observed in permanent teeth as a result of trauma to the corresponding temporary, with an incidence of 3%. In the literature there are only five cases involving dilaceration temporary incisors. The purpose of this article was to review and present a clinical case was a radiographic finding

Growth-associated changes in the periodontal bone and molar teeth of male rats.

Here we report quantitative data associating periodontal bone variables of young conventional rats with the growth process. The hemimandibles of male rats (IIM/Fm stock, 2 to 15 wk of age.) were excised and submitted to conventional morphologic, radiologic, and histologic evaluation. The length, area, or X-ray absorbance of various regions or structures was measured on digital images of radiographs by using an image-analysis program. The sum of periodontal bone areas undergoing resorption (interproximal + intraradicular) increased until 9 or 10 wk of age and decreased thereafter. Mineral accretion rates and mineral density asymptotes were not significantly different among molars. The mineral density of resorption areas in alveolar bone fitted sinusoidal kinetics, indicative of the 'instability' of the tissue due to its high metabolic activity. Mineral accretion rates and mineral density asymptotes were not significantly different among molars. The proportion of root length within alveolar bone exhibited a biphasic curve (minimum at 5 wk of age), due to differences in the growth rates of variables involved in its calculation (distance between the cementoenamel junction to the apex and height of the resorption areas). The distance between the cementoenamel junction and alveolar bone crest over time fitted a sigmoidal function with a point of inflection that did not differ significantly from that of body or mandible dry weight. In summary, the growth process appears to affect periodontal bone support and the distance between the cementoenamel junction and alveolar bone crest in male rats.

Root formation of an autotransplanted tooth.

Traumatic injuries with loss of anterior teeth occur more frequently in children. Treatment of the dental trauma is complex and requires a comprehensive and accurate diagnostic and treatment plan. It is also important to consider the biological, functional, esthetic, and economic aspects. The purpose of this article is to show a case report with a successful root formation and periodontal healing after autotransplantation of maxillary second right premolar in place of maxillary right central incisor site. Tooth autotransplantation may be considered as a viable treatment option instead of a conventional prosthetic and implant rehabilitation.

Dental maturity assessment in children with acute lymphoblastic leukemia after cancer therapy.

UNLABELLED: Dental age is largely used in both forensic studies and clinical practice. All over the world, many studies have been made to determine chronological age using dental ages of individuals, but selecting individuals with no chronic or acute sickness as the study group. Cancer is the second most frequent cause of death in children, and acute lymphoblastic leukemia (ALL) is the most common type of cancer in childhood. Most of the children who survived childhood cancer experienced disturbances in dental development due to cancer therapy or to cancer itself. The aim of this study is to assess dental development in children and teenagers who had suffered from childhood leukemia and were submitted to chemotherapy isolated or associated with radiotherapy, by comparing the dental ages with those corresponding features in a healthy control group. Dental development was analyzed using panoramic radiographs of 92 children divided in two groups: 46 children between 5 and 12 years old, treated for ALL at GRAACC-IOP, UNIFESP, and as a control group, 46 healthy children treated for dental reasons at APCD, São Paulo. The dental age of the subjects was estimated using the system of Demirjian et al. [A. Demirjian, H. Goldstein, J.M. Tanner, A new system of dental age assessment, Hum. Biol. 45(2) (1973) 211-227]. A significant difference was found between the chronological and dental age of patients submitted to antineoplasic therapy for ALL, when compared to those of the control group, but there were no significant differences between patients treated with different protocols for ALL. CONCLUSIONS: although the study was within a small group of patients, we could clearly conclude that antineoplastic therapy can interfere in the dental maturity of patients treated for childhood cancer by interfering in dental formation and root development.

Area of rests of Malassez in young and adult rat molars: evidences in the formation of large rests.

Recently, we have demonstrated that the reduction in the number of rests of Malassez (RM) according to age may be due to epithelial cell death by apoptosis. It is known that, under experimental or pathological conditions, the epithelial cells of RM can proliferate, resulting in the formation of odontogenic cysts and tumors. In this study, the area of RM profiles and the number of profiles of epithelial cell nuclei/RM were investigated in young and adult rats. Fragments containing upper molars of rats aged 29, 45, and 120 days were fixed, decalcified, and embedded for light microscopy. In the sections stained by hematoxylin and eosin, the numerical density of RM profiles/mm(2) of periodontal ligament, the area of each RM profile and the number of epithelial cell nuclei profile/RM were obtained. Moreover, detection of cytokeratin by immunohistochemistry and ultrastructural analysis of RM were carried out. Smaller RM were found in all groups, but the very large RM were only observed in the 120-day-old rats. The presence of cells in close juxtaposition exhibiting cytokeratin filaments in their cytoplasm, including in the large RM, characterized their epithelial nature. The number of epithelial cells/RM varied proportionally to the area. Moreover, epithelial cells in mitosis were found in small and large RM, indicating that cellular proliferation can be responsible for the enlargement of RM, under physiological conditions. The results suggest that a possible disequilibrium between the proliferative and apoptotic processes can be related to the enlargement of some RM in the 120-day-old rats.

Tooth transplantation after dental injury sequelae in children.

Ten immature autotransplanted lower premolars from six patients from 7 to 12 years of age were studied and assessed clinically and radiographically at Regional Clinical Hospital in Temuco between January 2004 and April 2006. All transplantations were performed both because of a missing anterior tooth by dental trauma or by healing complications after injuries. The mean age at the time of the surgery was 10 years (range 7-12 years) and the postoperative follow-up period varied from 5 to 27 months with a mean of 16.9 months. All teeth were stabilized with flexible composite resin wire splints. Within the follow-up period, clinical evaluation was made through percussion and mobility tests. At radiographic evaluation, pulpal canal obliteration (PCO), presence of perirradicular area, inflammatory root resorption (IRR), replacement resorption (RR), stage of root development, lamina dura formation, outline of the periodontal membrane, and arrest in root growth were registered. Pulp healing was observed in 6 of 10 teeth; the other transplanted teeth developed pulp necrosis after 6-8 months possibly related to operative aesthetic procedures. Four teeth showed different grades of PCO at radiographic examination. None of transplanted teeth developed replacement resorption or ankylosis. In this 27-month follow-up period, the survival rate was 100%, regarding aesthetics, function, clinical appearance, and radiographic image of alveolar process.

Correlation of the radiographic and morphological features of the dental follicle of third molars with incomplete root formation.

The objective of this study was to determine the correlation of the radiographic and morphological features of the dental follicle of unerupted third molars with incomplete root formation. A cross-sectional study was carried out with 56 patients (105 teeth) aged 13 to 24 years. Panoramic radiography was used to determine the stage of root formation to locate and measure pericoronal radiolucency. The width of the dental follicle ranged from 0.0 to 4.0 mm, the distal face being the one most frequently involved, and stage 7 of root formation showing the highest incidence. An inactive enamel reduced epithelium and inactive epithelium remnant also showed a high incidence. Dense connective tissue showed a high incidence, chronic inflammation was infrequent and calcification was a common finding. There was a significant association between the progression of the rhizogenesis and the transformation of the enamel reduced epithelium into a stratified squamous epithelium. No significant association was found between rhizogenesis and the other morphological findings or between the latter and the width of the pericoronal space. It was concluded that there was no clinically significant correlation between the radiographic and morphological features. Every asymptomatic unerupted third molar should be followed up and the follicular tissue analyzed.

Variation in the expression of insulin-like growth factor-1 in human pulp tissue according to the root-development stage.

Insulin-like growth factor-1 (IGF-1) plays an important role in cell proliferation and differentiation. It actively participates during odontogenesis and mineralization of dental hard tissues. The purpose of this study is to use a radioimmunoassay (RIA) to determine whether there are differences in the expression of IGF-1 in human pulp from teeth having incomplete or complete root development. Twenty-six pulp samples were obtained from freshly extracted human third molars, half of them from teeth with incomplete root development. All of the samples were processed and labeled using an IGF-1 RIA kit. Results showed IGF-1 presence in all human pulp samples with a statistically significant higher expression in pulps having complete root development. The present findings are consistent with the hypothesis that IGF-1 contributes toward forming and mineralizing dental tissues in teeth with incomplete root development as well as in pulp-repairing process in teeth with complete root development.

Effects of alendronate on tooth eruption and molar root formation in young growing rats.

Tooth eruption consists of the movement of teeth from the bony crypt in which they initiate their development to the occlusal plane in the oral cavity. Interactions between the tooth germ and its surrounding alveolar bone occur in order to offer spatial conditions for its development and eruption. This involves bone remodeling during which resorption is a key event. Bisphosphonates are a group of drugs that interfere with the resorption of mineralized tissues. With the purpose of investigating the effects of sodium alendronate (a potent bisphosphonate inhibitor of osteoclast activity) on alveolar bone during tooth development and eruption, we gave newborn rats daily doses of this drug for 4, 14, and 30 days. Samples of the maxillary alveolar process containing the tooth germs were processed for light, transmission, and scanning electron microscopy and were also submitted to tartrate-resistant acid phosphatase histochemistry and high-resolution colloidal-gold immunolabeling for osteopontin. Inhibition of osteoclast activity by sodium alendronate caused the absence of tooth eruption. The lack of alveolar bone remodeling resulted in primary bone with the presence of latent osteoclasts and abundant osteopontin at the interfibrillar regions. The developing bone trabeculae invaded the dental follicle and reached the molar tooth germs, provoking deformities in enamel surfaces. No root formation was observed. These findings suggested that alendronate effectively inhibited tooth eruption by interfering with the activation of osteoclasts, which remained in a latent stage.

Structural resistance in immature teeth using root reinforcements in vitro.

The purpose of this study was to evaluate in vitro the efficacy of root reinforcements by light-cured composite resin or zirconium fiber post in simulated immature non-vital teeth. Fifty-six bovine incisors teeth were used for this study. The crown of each tooth was removed in the medium third to obtain a standard length of 30 mm. The specimens were divided into four groups (n = 14): G1) the root canals were instrumented and enlarged to simulate immature non-vital teeth and were reinforced with a light-cured composite resin using a translucent curing post (Luminex system); (G2) the specimens were instrumented, enlarged and they received root reinforcement with zirconium fiber post; G3 (positive control): they received similar treatment to the G1 and G2 groups, but did not receive root reinforcement; G4 (negative control): the roots were not weakened and did not receive reinforcement. Every tooth was submitted to compressive force using an Instron testing machine with an angle of 45 degrees at a speed of 1 mm min(-1) until the fracture. The results showed a markedly increased resistance to fracture in the G1 and G2 (122.38 and 122.08 kg f, respectively). Among the results of G1 and G2 there was not any significant difference (P > 0.05) but they were significantly different from the control groups (P < 0.05). The conclusion is that the use of root reinforcements with zirconium fiber post or composite resin can increase significantly the structural resistance of the weakened teeth, decreasing the risk of the fracture.