Long-term stability of curve of Spee depth among orthodontically treated patients: A retrospective longitudinal study.

OBJECTIVE: The curve of Spee is deemed important characteristic of the dentition for a balanced occlusion and distribution of masticatory forces, while orthodontic levelling of an accentuated curve of Spee is generally included as a treatment goal for deepbite correction. However, relapse is often seen and can be problematic. METHODS: A retrospective longitudinal study of predominantly young patients with a deep curve of Spee, who had been treated orthodontically with 0.018"-slot Edgewise fixed appliances, was performed. The depth of the curve of Spee was digitally measured before treatment (T1), at debond (T2), and an average of 7 years post-debond (T3) and analysed statistically at 5%. RESULTS: A total of 157 patients were included (56.7% female; 11.6-year-old at T1), 16.6% of which were treated with premolars extractions. Non-extraction treatment reduced the curve of Spee at the first premolar from 1.87 mm (T1) to 0.22 mm (T2), which relapsed 0.12 mm (T3; P = .04). The respective depths for the second premolar were 2.0 mm (T1), reduced to 0.80 mm (T2). No significant relapse was seen for the second premolar (0.08 mm; P > .05) or the first permanent molar (0.06 mm; P > .05). No overall significant differences in absolute relapse were seen between extraction and non-extraction patients, but premolar extractions were associated with less clinically relevant relapse at the first molar (odds ratio 0.27; 95%-confidence interval 0.08-0.88; P = .003). CONCLUSION: Steep curves of Spee can be satisfactorily levelled orthodontically with satisfactory stability in the long term, while premolar extractions might be associated with less relapse.

Adverse effects of chemotherapy on the teeth and surrounding tissues of children with cancer: A systematic review with meta-analysis.

OBJECTIVE: The aim of this systematic review was to assess evidence on dental adverse effects associated with chemotherapy (CH) administered to children with cancer. MATERIAL AND METHODS: Eight databases were searched without restrictions up to March 2017 for studies reporting on dental effects of CH administered for childhood cancer. After elimination of duplicates, data extraction, and risk of bias assessment according to the Cochrane guidelines, random-effects meta-analyses of Relative Risks (RR) and Mean Differences (MD) and their 95% Confidence Intervals (CI) were performed, followed by meta-regression and sensitivity analyses. RESULTS: The literature search identified a total of 15 non-randomized case-control studies including at least 2315 patients (mean age at diagnosis or CH of 6.6 years; 36% male) followed for up to 22.9 years after CH. Meta-analysis indicated that CH was associated with increased risk for tooth agenesis compared to healthy controls (RR = 2.47; 95% CI = 1.30-4.71; P = 0.006). This translated to every seventh child with CH having agenesis of at least one tooth that would not otherwise have. Additionally, CH was significantly associated with increased risk of tooth discoloration, arrested tooth development, enamel hypoplasia, microdontia, premature apexification, and decreased salivary flow rate, as well as worse oral hygiene and greater caries experience compared to controls. However, the strength of evidence was very low due to the inclusion of non-randomized study designs with high risk of bias. CONCLUSIONS: Current evidence from childhood cancer survivors indicates that chemotherapy is associated with considerable dental adverse effects that might be associated with greater burden of disease and treatment costs.