Rasmussen, Chad M.

AbstractPurposeDental amalgam contains mercury and is commonly used in dental restorations. The impact of MRI on mercury excretion from dental amalgam is not well understood across clinical field strengths, especially 7T. We investigated the effects of MRI exposure on mercury excretion using fresh, lab‐created dental amalgam restorations and in extracted teeth with old, pre‐existing restorations.MethodsDonated, unfilled human teeth (n = 120) were restored with amalgam before being stored in saline, artificial saliva, or a dry box prior to MRI scanning. The teeth were placed in individual tubes of fresh artificial saliva and scanned at 1.5T, 3T, or 7T or left unscanned as controls. Mercury concentrations were measured 24–30 h later. Donated teeth with pre‐existing restorations (n = 40) were stored in artificial saliva, scanned at 7T or left unscanned as controls, and mercury concentration tested.ResultsFor teeth extracted and restored in a laboratory, no significant difference was found (F = 2.42, P = 0.072) between mean mercury concentrations of unscanned teeth (13.72 μg/L) and teeth scanned at 1.5T (10.88 μg/L), 3T (12.65 μg/L), or 7T (8.88 μg/L). For teeth extracted with previously placed restorations, no significant difference (P = 0.288) was found between unscanned controls (4.28 μg/L) and teeth scanned at 7T (6.63 μg/L).ConclusionMRI of dental amalgam does not significantly increase mercury excretion at 1.5T, 3T, or 7T compared to unscanned teeth. This holds true for controlled laboratory restorations as well as for those placed and lived with prior to extraction and scanning, demonstrating no added risk to the clinical patient or research subject.

Abstract Introduction Obstructive Sleep Apnea (OSA) in children and adolescents is commonly discussed amongst dental specialists. Physical attributes such as a high and narrow palate, dolichofacial appearance, and retrognathic mandible are reported to increase pediatric risk for OSA. Previous research states rapid maxillary expansion decreases AHI in children with OSA and may be an effective treatment option. Current literature does not report a consistent method of measuring a maxillary transverse deficiency nor does it report a numerical maxillary threshold deficiency that requires expansion in pediatric patients with OSA. Our aims are to compare two different orthodontic diagnostic methods for measuring the maxillary transverse dimension and to assess whether patients diagnosed with mild, moderate, or severe OSA have a numerical threshold for maxillary deficiency. Methods Participants were ages 7-17 years old (average 11.7 years) with no history of orthodontic treatment, craniofacial syndromes, craniosynostosis forms, or nasal abnormalities. Those with and without adenoids and tonsils were included. Participants presented to the Mayo Clinic Sleep Center for their polysomnogram. Their dentition was scanned, and a digital model was rendered. The maxillary transverse dimension was measured via two different methods: McNamara’s Analysis and Andrew’s Six Elements of Orofacial Harmony. Results There were 65 participants: 31 diagnosed with OSA (13 Mild, 4 Moderate, 5 Severe, and 9 Other) and 34 without (controls). Patients in the Other category were diagnosed based on clinical findings. No statistical difference was found between the maxillary transverse measurements of patients with versus without OSA or between the OSA categories. Patients with OSA were more likely to have permanent teeth (61.3% vs 32.4%, p=0.019), tonsils removed (54.8% vs 26.5%, p=0.020), and to have snored during the PSG (83.9% vs 55.9%, p=0.048). Conclusion Conclusions based on this pilot study should be interpreted carefully due to limited sample sizes. No statistically significant differences of the maxillary transverse dimension were found between those with and without OSA using either diagnostic method. No numerical maxillary deficiency threshold was found. Maxillary expansion should not be recommended based on OSA diagnosis alone. Referral to a dental specialist is recommended based on dental needs. Support (if any) Support was provided by Mayo Clinic CTSA grant UL1TR002377.

AbstractAmyloidosis of the tongue can result in significant and irreversible alterations of tooth position and function due to prolonged application of imbalanced force on the teeth by the enlarged tongue. Due to the rarity of this oral form of systemic disease, little has been elucidated on management of the resulting impaired oral function. While surgery can address the size of the tongue, it carries significant morbidities, enlargement can recur, and does not address adverse tooth positioning. Prosthetic rehabilitation can more aptly restore oral function but it also needs to be tailored based on the patient's expectations and goals as well as biologic and mechanical parameters of treatment. This report discusses an effective and noninvasive application of a tooth‐supported, removable prosthesis with an onlay occlusal design to restore occlusion, speech, and esthetics in a patient with tongue‐based amyloidosis.