Comprehensive dental treatment for "meth mouth": a case report and literature review.

Methamphetamine-induced caries (MIC) is the rampant caries often found in methamphetamine (MA) users and is often called "meth mouth". It leads to devastating effects on dentition and is the major reason that brings patients to professional help. Dental management of these patients is challenging and the most important factor is cessation of MA use. Dentists must be aware of the signs and medical risks associated with this serious condition. If duly attended to, the dental team can help patients on many levels. Treatment plans can be simplified, so that each visit does not last too long. Finally, more attention should be paid topostoperative care. This case report presents a 40-year-old man with rampant caries caused by MA abuse with poor oral hygiene and smoking habits. He was advised to stop the drug abuse and the affected teeth underwent endodontic, restorative and prosthetic rehabilitation. One year later, the patient had some secondary caries but had stopped all drug abuse.

Stress distribution in a mandibular premolar after separated nickel-titanium instrument removal and root canal preparation: a three-dimensional finite element analysis.

OBJECTIVE: This study used finite element analysis (FEA) to assess the von Mises stresses of a mandibular first premolar after removing a separated instrument with an ultrasonic technique. METHODS: FEA models of the original and treated mandibular first premolar were reconstructed, and three models (the original canal, size 30/taper 0.04 canal, and separated instrument removal canal) were created. Two-direction (vertical and lateral) loading patterns were simulated with a 175-N force. The maximum von Mises stresses of the models within the roots from the apex to the cervical region were collected and summarized. RESULTS: Under vertical and lateral loads, all maximal values in the three models were localized in the straight-line access region. Compared with the original model (model 1), the treated models (models 2 and 3) had greater maximum stress values from the apex to the cervical region. Greater differences in the maximum von Mises stresses between models 2 and 3 were present in the straight-line access region. CONCLUSIONS: Separated instrument removal caused changes in stress distribution and increases in stress concentration in the straight-line access region of roots.