Direct resin composite restoration of endodontically-treated permanent molars in adolescents: bite force and patient-specific finite element analysis

Abstract

Direct resin composite restoration of endodontically-treated permanent molars in adolescents: bite force and patient-specific finite element analysis Objective: To evaluate the influence of three levels of dental structure loss on stress distribution and bite load in root canal-treated young molar teeth that were filled with bulk-fill resin composite, using finite element analysis (FEA) to predict clinical failure. Methodology: Three first mandibular molars with extensive caries lesions were selected in teenager patients. The habitual occlusion bite force was measured using gnathodynamometer before and after endodontic/restoration procedures. The recorded bite forces were used as input for patient-specific FEA models, generated from cone-beam computed tomographic (CT) scans of the teeth before and after treatment. Loads were simulated using the contact loading of the antagonist molars selected based on the CT scans and clinical evaluation. Pre and post treatment bite forces (N) in the 3 patients were 30.1/136.6, 34.3/133.4, and 47.9/124.1.Results: Bite force increased 260% (from 36.7±11.6 to 131.9±17.8 N) after endodontic and direct restoration. Before endodontic intervention, the stress concentration was located in coronal tooth structure; after rehabilitation, the stresses were located in root dentin, regardless of the level of tooth structure loss. The bite force used on molar teeth after pulp removal during endodontic treatment resulted in high stress concentrations in weakened tooth areas and at the furcation. Conclusion: Extensive caries negatively affected the bite force. After pulp removal and endodontic treatment, stress and strain concentrations were higher in the weakened dental structure. Root canal treatment associated with direct resin composite restorative procedure could restore the stress-strain conditions in permanent young molar teeth.

Mechanical Behavior of Different Restorative Materials and Onlay Preparation Designs in Endodontically Treated Molars

“…A possible limitation of the study is that the simulated mesio-occluso-distal cavity was designed arbitrarily with the CAD software, and not made from a real clinical condition such as those simulated in patient-specific FEA studies. Probably, a patient-specific assessment could bring new information about the effect of the preparation design [26,73]. In addition, the simulated occlusal contact generates loads in the axial direction [74]; horizontal loads could simulate more critical effects on tooth, cement layer, and restoration.…”

Abordagem interdisciplinar em molares de pacientes jovens, o desafio para evitar a extração prematura

“…Reabilitar dentes de pacientes jovens com lesões periapicais e grande perda de estrutura dentária, com prognóstico incerto, se caracteriza como grande desafio ao cirurgião-dentista. Além das dificuldades técnicas relacionadas ao tratamento endodôntico de molares jovens, as quais são pouco discutidas na literatura 8 , tem-se também o desafio restaurador, que deve sempre buscar simplificação técnica e baixo custo 12 . No caso clínico 2, foi também necessária à realização de cirurgia periodontal a fim de restabelecer o espaço biológico, permitir reconstrução coronária e realização de adequado isolamento absoluto.…”

“…Em relação à alternativa reabilitadora, coroas totais apresentam baixa indicação nessa faixa etária, uma vez que o indivíduo ainda apresenta crescimento facial. No entanto, as resina híbridas convencionais demandam maior tempo pela inserção em vários incrementos, com isso, resinas bulk fill surgiram como alternativa para esses casos 12,30-32 mostrando desempenho mecânico e estético satisfatório 33 , sendo executadas em uma única sessão, com menor custo que as restaurações indiretas.…”

Selective carious tissue removal and glass ionomer liner reduction of pulp stress in bulk fill resin composite restorations

“…The third null hypothesis was also rejected; selective removal of carious tissue following the RMGIC liner affected the stress distribution at the pulp chamber ceiling. Dentin is composed of inorganic material structures, [31][32][33] distributed throughout the crown and root, which contribute to the absorption and distribution of stresses within the tooth. Prior to undertaking any FEA-based simulation, it is critical to determine the material properties of carious tissues.…”

“…32 Direct adhesive restoration that recovers the biomechanical principles of deep carious lesion molar teeth is mandatory for preventing the necessity of endodontic treatment or tooth extraction. 33 The selective removal of carious dentin tissue has been recommended for teeth with deep carious lesions and the absence of irreversible pulpal or periapical diseases to preserve a maximum dental structure and to reduce the possibility of pulpal exposure. 34 Soft and firm dentin were removed, and the underlying hard carious dentin tissue was preserved to avoid pulpal complications.…”