Effect of GaAIAs laser on reactional dentinogenesis induction in human teeth

OBJECTIVE

This study investigated the biomodulatory effect of the gallium- aluminum-arsenate laser (GaAlAs) in pulp cells on reactional dentinogenesis, and on the expression of collagen type III (Col III), tenascin (TN), and fibronectin (FN) in irradiated dental tissues and controls (not irradiated).

BACKGROUND DATA

Several studies suggest a biomodulatory influence of low-intensity laser radiation in the inflammatory and reparative processes of biological tissues.

METHODS

Sixteen human premolar teeth were selected (after extraction due to orthodontal reasons) and divided into irradiated and control groups. Black class V cavity preparations were accomplished in both groups. For the irradiated group, GaAlAs laser (670 nm, 50 mW) with an energy density of 4 J/cm2 was used. Soon after, the cavities were restored with a glass ionomer and the extractions made after 14 and 42 days.

RESULTS

Histological changes were observed by light microscopy; less intense inflammatory reaction in the irradiated group was found when compared to the controls. Only the irradiated group of 42 days exhibited an area associated with reactional dentinogenesis. After immunohistochemical analysis by the streptoavidin-biotin complex (SABC) method, the expression of Col III, TN, and FN was greater in the irradiated groups.

CONCLUSION

Our results suggest that a GaAlAs laser with energy density of 4 J/cm2 and wavelength of 670 nm caused biomodulation in pulp cells and expression of collagen, but not collagen of the extracellular matrix, after preparation of a cavity.

Evaluation of a modified hemimandibulectomy for treatment of oral neoplasms in dogs

A modified hemimandibulectomy was performed for treatment of oral neoplasms in 21 dogs. Intra- and postoperative evaluations included assessment of procedure difficulty, complications, mastication, cosmesis, and the time interval between surgery and recurrence of the neoplasm or clinical evidence of metastasis. Malignant melanoma was the most common neoplasm treated using this technique. The modified hemimandibulectomy was uncomplicated with minimal intraoperative hemorrhage. Three dogs had difficult mastication at 24-hours following surgery, while 5 dogs had partial wound dehiscence. Wound infection was diagnosed in 1 dog. All owners considered the postoperative outcome to provide acceptable cosmesis. Local neoplasm recurrence was documented in 5 dogs and distant (pulmonary) metastasis was diagnosed in 5 different dogs following surgery. The technical modification described in this study seemed to provide for improved mastication during the acute postoperative period compared with other hemimandibulectomy techniques performed by the authors.