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Concurrent impaction and transposition of maxillary anterior teeth is uncommon and poses a challenge for dentists. Early diagnosis and management of eruption disturbances benefits esthetic and functional outcomes. This article describes the treatment of a teenager who had impactions of the left maxillary central incisor and canine as well as ipsilateral canine-lateral incisor transposition. Treatment alternatives and effective orthodontic techniques are delineated. To optimize the treatment results, the impacted maxillary canine was surgically exposed and orthodontically distalized with an innovative cantilever. Subsequently, the deeply impacted maxillary central incisor was uncovered and orthodontically mesialized into the arch. Finally, the displaced maxillary lateral incisor was brought into its normal position. The combined surgical-orthodontic approach resolved a difficult clinical issue and avoided additional restorations. An esthetic, functional outcome was achieved and satisfied the patient.

Objective: To determine the prevalence and severity of impacted permanent mandibular second molars (MdM2s) in the general population of Taiwan as well as to evaluate treatment outcomes with an innovative method for impacted MdM2s., Materials and Methods: Dental records of 21,580 patients were retrospectively screened in this study. The impactions of MdM2s were registered. The chosen study population consisted of 96 patients with 125 impacted MdM2s who received orthodontic treatment in our clinics. Standardized periapical radiographs were taken to measure the angles and depths of the impacted MdM2s. In addition, the initial uprighting periods of the impacted MdM2s were recorded., Results: The prevalence of MdM2 impaction in the Taiwanese population was 0.65%. Most of the angles and depths of the MdM2s were 31-60° and 9-12 mm, respectively. The mean initial uprighting period of the impacted MdM2 was 3.6 months. There were no significant differences between genders in the initial uprighting period based on patient ages, impacted angles, or impacted depths (P > .05). Correlation analysis revealed that the impacted depth was highly and positively correlated with the initial uprighting period (r > .75)., Conclusions: The prevalence of MdM2 impaction in this study was low but slightly higher than previous reports investigating whites. Although such impactions are rare, it is recommended to diagnose early for an optimal treatment time and reduction of complications. In addition, the effective molar uprighting appliance used in this study has displayed good treatment outcomes with natural improvement of the adjacent infrabony defects of the first molars.

Simultaneous impactions of first, second, and third permanent molars comprises a very rare clinical situation with diverse therapeutic approaches and is a difficult challenge for dentists. Early diagnosis and treatment of eruption disturbances contributes to optimal outcomes. This article reports the treatment of a teenager with severe impaction of right mandibular first, second, and third molars, which hinders the masticatory function and dental arch integrity. A decision-making process and a simple orthodontic technique are described. To shorten the treatment time and simplify the procedures, the impacted right mandibular third and second molars were orthodontically uprighted with an innovative tip-back cantilever. Subsequently, the deeply impacted right mandibular first molar was extracted with minimal obstacles. The combined surgical-orthodontic approach resolved a challenging clinical problem and eliminated the need for prosthetic or dental implant replacement of the impacted molars. Good occlusion, normal function, and a healthy periodontium of the patient were also achieved.

Objective: To test the hypothesis that different nickel-titanium (NiTi) archwires may have dissimilar corrosion resistance in a fluoride-containing oral environment., Materials and Methods: Linear polarization test, a fast electrochemical technique, was used to evaluate the corrosion resistance, in terms of polarization resistance (R(p)), of four different commercial NiTi archwires in artificial saliva (pH 6.5) with various NaF concentrations (0%, 0.01%, 0.1%, 0.25%, and 0.5%). Two-way analysis of variance was used to analyze R(p) with the factors of archwire manufacturer and NaF concentration. Surface characterizations of archwires were analyzed using scanning electron microscopy, atomic force microscopy, and x-ray photoelectron spectroscopy., Results: Both archwire manufacturer and NaF concentration had a significant influence on R(p) of NiTi archwires. Different surface topography was present on the test NiTi archwires that contained the similar surface chemical structure (TiO(2) and trace NiO). The surface topography did not correspond to the difference in corrosion resistance of the NiTi archwires. Increasing the NaF concentration in artificial saliva resulted in a decrease in R(p), or corrosion resistance, of all test NiTi archwires. The NiTi archwires severely corroded and showed similar corrosion resistance in 0.5% NaF-containing environment., Conclusions: Different NiTi archwires had dissimilar corrosion resistance in acidic fluoride-containing artificial saliva, which did not correspond to the variation in the surface topography of the archwires. The presence of fluoride in artificial saliva was detrimental to the corrosion resistance of the test NiTi archwires, especially at a 0.5% NaF concentration.