Po-Sung Fu

Impacted mandibular second molars.

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.

Management of unilaterally deep impacted first, second, and third mandibular 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.

Three-dimensional relationship of the maxillary anterior teeth to the incisive papilla in young adults.

The use of the incisive papilla as an important guide for setting maxillary teeth has been applied in prosthetic dentistry. The purpose of this study was to estimate the relationship between maxillary anterior teeth and the incisive papilla of young adults with approximately optimal occlusion in Taiwan. Study casts of 100 young adults (50 males, 50 females; mean age, 22.4 years) were selected in this study. All of the marked points on maxillary casts were measured using a three‐dimensional precise measuring device. The relative positions of maxillary teeth landmarks to incisive papilla were measured and analyzed using SAS software (JMP 4.02). Students t test and Pearsons correlation test were used to test the statistical significance of any differences (p < 0.05). The results showed that the mesiolabial incisal edge of the upper central incisor was 7.30 ± 0.64mm anterior to the center of the incisive papilla. There was no significant difference in gender (p > 0.05). The intercanine line was 0.27 ± 1.30 mm posterior to the center of incisive papilla. There was no significant difference in gender (p > 0.05). The horizontal distances of the mesiolabial incisal edge of the upper central incisor and the intercanine line to the center of the incisive papilla showed only weak correlation (r < 0.5). In addition, the three‐dimensional relationship of maxillary anterior teeth to the center of the incisive papilla was measured and analyzed. We suggest using the incisive papilla as a reference landmark for the setting of maxillary anterior teeth.

Uprighting Impacted Mandibular Permanent Second Molars with the tip-back Cantilever Technique Cases Report

Very severe inclination of the mandibular second molar is a difficult challenge for dentists. Severe impaction of the mandibular second molars often leads to their extraction to avoid potential damage to the root of the first molars and provide space for the eruption of the third molars. An ideal treatment is orthodontic uprighting with or without surgical uncovering, and one of the effective appliances for molar uprighting is the tip-back cantilever technique. This paper presents the successful tip-back sectional archwire orthodontic treatment of impacted mandibnlar second molars.

Optimizing anterior esthetics of a single-tooth implant through socket augmentation and immediate provisionalization: A case report with 7-year follow-up

Tooth extraction inevitably accompanies alveolar ridge resorption with loss of pre‐existing tissue morphology. Replacing missing teeth with dental implants has become popular, but restoring anterior teeth with implant‐supported restorations is a technique‐sensitive task and poses challenges for dentists. With the progress of implant dentistry, the demand for optimal esthetics has become linked with the desire for faster, easier techniques that shorten treatment time and also satisfy patients. Immediate provisionalization of a single‐tooth implant provides significant benefits compared with traditional delayed protocols, such as aiding the contouring of peri‐implant soft tissue and enhancing patient comfort and satisfaction. This article describes a meticulous approach to a hopeless maxillary central incisor with root fracture. The defect in the extraction socket was reconstructed using autogenous bone harvested from the chin. Four months later, an implant was installed and immediately restored. After another healing period of 6 months, the peri‐implant soft tissue had been shaped and matured according to the contours of the provisional restoration. The emergence profile was used to duplicate the definitive restoration. Peri‐implant esthetics was achieved through socket augmentation and immediate provisionalization of the implant. This treatment modality attained predictable and maintainable outcomes, both functionally and esthetically.

Unilaterally impacted maxillary central incisor and canine with ipsilateral transposed canine-lateral incisor

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.

Immediate implant placement following minimally invasive extraction: a case report with a 6-year follow-up.

Single tooth replacement with a dental implant has become an increasingly favored treatment option in the anterior maxilla; however, bone resorption following maxillary anterior tooth extraction is very common and often compromises gingival tissue for the implant restoration. Achieving predictable peri‐implant esthetics requires a proper understanding and preservation of the osseous and gingival tissue surrounding the failing tooth. Therefore, the key to maintaining the interproximal papillae is to preserve the osseous support with minimally invasive extraction. An immediate implant insertion after tooth extraction may maintain the crest bone and the interdental papillae, thus achieving peri‐implant esthetics. This article describes the detailed treatment planning and meticulous techniques in immediate implant placement that reduce treatment time and maintain functional as well as esthetic results through a 6‐year follow‐up.

The possibility of recasting of pure titanium

Background/purpose Pure titanium (Ti) has many advantages, such as high corrosion resistance and excellent biocompatibility. The mechanical properties of pure Ti are like those of type IV gold alloys. Furthermore, gold alloys can be successfully recast in dental clinics. The aim of this study was to investigate the possibility of recasting pure Ti. Materials and methods Magnesium oxide (MgO)-based investment that contained a 5 wt. % zirconium dioxide (ZrO2) additive was used. An argon-casting machine (Castmatic-S, Iwatani) was used to recast pure Ti. The first generation and second generation pure Ti (50 wt. % new Ti + 50 wt. % surplus Ti) were used. Five specimens were fabricated and tested. The data were evaluated using two-sample t-test analysis (P < 0.05). Results The experimental results showed that recasting the Ti did not decrease the marginal accuracy, average surface roughness, Vickers hardness value of the superficial surface, and the thickness of the reaction layer. Conclusion This study clearly showed Ti could be recast when a 5 wt. % ZrO2 additive MgO-based investment was used. This modified investment has the potential for use in clinical applications.

Immediate provisional restoration of a single-tooth implant in the esthetic zone: A case report

Immediate implant restoration of single implants may demonstrate a positive effect on peri‐implant soft tissue. Placement of a provisional restoration following implant surgery can create soft tissue contours that resemble normal gingival topography before placement of the definitive prosthesis. This article describes a staged approach of the mandibular permanent right central incisor, which was congenital missing. The proper space for restoration of the missing incisor was created through orthodontic treatment. The scheduled implant site was reconstructed using autogenous bone harvested from the chin region. After a healing period of four months, an implant was installed with the connection of a fixed provisional crown to a prefabricated temporary abutment. The soft tissue around the implant healed according to the contours of the provisional restoration and the emergence profile was used to duplicate the definitive restoration. Peri‐implant esthetics was achieved through the staged approach and immediate restoration of the implant.