Yuka Takahashi

Clinical Evaluation of an Unsintered Hydroxyapatite/Poly-L-Lactide Osteoconductive Composite Device for the Internal Fixation of Maxillofacial Fractures

Introduction:OSTEOTRANS MX (Takiron Co, Ltd, Osaka, Japan) is a resorbable osteosynthetic material composed of an unsintered hydroxyapatite/poly-L-lactide composite, and its osteoconductive capacity has been documented. The authors here report their clinical experience using OSTEOTRANS MX. Methods:The authors treated 35 patients (19 men, 16 women; age, 14–88 years; mean ± standard deviation, 38.4 ± 19.9 years) with maxillofacial fractures. The authors used standard surgery to stabilize fractures in all patients, fitting resorbable plates (thickness, 1.0 or 1.4 mm) and screws (diameter, 2 mm) according to Arbeitsgemeinschaft für Osteosynthesefragen/Association (AO) for the Study of Internal Fixation guidelines. Results:All patients eventually achieved satisfactory healing with favorable restoration of form and function without foreign body reaction. Complications occurred in 3 patients—plate exposure in 2 and discomfort in 1. However, fracture sites healed in all patients. Scanning electron microscopy revealed that the devices bonded directly to the bone without interposition of nonmineralized tissue. Conclusion:OSTEOTRANS MX is a useful material with few complications. Its osteoconductive bioactivity is advantageous for the early functional improvement of maxillofacial fractures.

Use of templates and self-tapping metal screws for temporary fixation of a resorbable plate system

Resorbable plate systems combine the benefits of rigid internal fixation with the convenience of biodegradation; thus, precluding the need for removal and reducing their interference with craniofacial growth. However, in surgeries involving maxillofacial bone, when reduction or repositioning of the bone segment is inaccurate, refixation and rebending of the plate may be necessary. Here, we report using a temporary plate with self-tapping metal screws to avoid repeated rebending of the resorbable plate and using additional screws following inaccurate fixation in maxillofacial surgeries.

Use of a Piezosurgery Technique to Remove a Deeply Impacted Supernumerary Tooth in the Anterior Maxilla

Deeply impacted supernumerary teeth in the anterior maxillary cannot be generally removed by the conventional labial or palatal surgical approach because of the risk of damaging the surrounding soft tissues and the possibility of injuring the roots of adjacent permanent teeth. In piezosurgery, bony tissues are selectively cut, thereby avoiding the soft tissue damage caused by rotary cutting instruments. We report the case of a 15-year-old Japanese boy from whom a deeply impacted supernumerary tooth in the anterior maxillary was safely removed through the floor of the nasal cavity. The surgical extraction was performed without damaging the nasal mucosa or adjacent structures such as the roots of the adjacent permanent teeth. Considering that piezosurgery limits the extent of surgical invasion, this technique can be practiced as a minimally invasive and safe surgical procedure for treating suitably selected cases with a deeply impacted supernumerary tooth.

Use of the bioactive resorbable plate system for zygoma and zygomatic arch replacement and fixation with modified Crockett's method for maxillectomy: A technical note

As a surgical approach targeting the pterygopalatine fossa following maxillary cancer due to tumor invasion, Crocketts method is conventional and useful. However, if the tumor is confined to the area between the maxilla and pterygopalatine fossa, it is not necessary to include the zygomatico-orbital in the access osteotomy, and the orbital floor may be preserved. Depending on the range of tumor invasion, the current study reports a more minimally invasive, modified Crocketts surgery that may be considered, which includes resection with modified osteotomy lines and repositioning with fixation of the zygoma and zygomatic arch following maxillary cancer ablation. In addition, the majority of patients with advanced maxillary cancer may require postoperative radiotherapy or chemoradiotherapy following maxillectomy according to several guidelines. Therefore, using a low-profile bioactive resorbable plate system as a method of repositioning and fixing the resected and preserved zygoma and zygomatic arch may be more effective in this modified Crocketts method for maxillectomy.

Primary intraosseous squamous cell carcinoma of the maxilla possibly arising from an infected residual cyst: A case report

Primary intraosseous squamous cell carcinoma (PIOSCC) is a rare type of odontogenic carcinoma arising from the jawbone. Odontogenic cysts are true cysts that arise from the dental epithelium, which is associated with tooth formation. The epithelial lining of odontogenic cysts has the potential to transform into various types of odontogenic tumor; however, this transformation from an odontogenic cyst to a malignant tumor is rare. The definitive diagnosis for PIOSCC generally requires the observation of either features of squamous cell carcinoma (SCC) within the jawbone that are distinct from direct invasion from the surface oral epithelium, or evidence of SCC arising from odontogenic epithelium and from tumors that have metastasized to the jawbone from distant sites. In the present study, a case of PIOSCC of the maxilla is presented, which, based on the results of computed tomography and the clinical course, was hypothesized to have originated from an infected residual cyst.