Histomorphometrical and radiological comparison of low-level laser therapy effects on distraction osteogenesis: experimental study.

Distraction osteogenesis (DO) is the application of traction to the callus formed between bone segments and stimulation of bone formation by creating stress on the callus with this traction. Shorten the duration of DO and increasing the capacity of bone formation is important to prevent the possible complications of DO. For this reason, it was considered that low-level laser therapy (LLLT) may affect positively DO and it can decrease the complication range by shortening the period. Unilateral mandibular distractors were applied on 16 female white New Zealand rabbit to prove this hypothesis with micro CT, plain radiograph and histomorphometric analyses. Eight rabbits were applied LLLT with GaAlAs laser on the distraction area during the distraction period. On the post-distraction 28th day, four rabbits from study group and four rabbits from control groups were sacrificed. The rest of the rabbits were sacrificed on post-distraction 56th day. As a result of this study, significant positive effects of LLLT on post-distraction 28th day were revealed with all analyses. In histomorphometrical analyses, new bone formation was significantly higher in short-term laser applied group comparing to that of short-term control group (p = 0.029). In both microCT and plain radiograph, the highest radioopacity values were observed in short-term laser group when compared with that of the controls (p = 0.043 and p = 0.025, respectively). Even though LLLT increased the healing capacity on short-term, it was not sufficient on long-term (post-distraction 56th day) healing. LLLT application on distraction period, activate healing on bone so it may decrease DO period. The result of this study should be supported with clinical studies and the most effective laser source, dose and application time should be revealed with experimental and clinical studies.

Effect of low-level laser therapy (LLLT) on orthodontic tooth movement.

The aim of this study is to evaluate the effects of low-level laser therapy (LLLT) on (1) the velocity of orthodontic tooth movement and (2) the nitric oxide levels in gingival crevicular fluid (GCF) during orthodontic treatment. The sample consisted of 20 patients (14 girls, six boys) whose maxillary first premolars were extracted and canines distalized. A gallium-aluminum-arsenide (Ga-Al-As) diode laser was applied on the day 0, and the 3rd, 7th, 14th, 21st, and 28th days when the retraction of the maxillary lateral incisors was initiated. The right maxillary lateral incisors composed the study group (the laser group), whereas the left maxillary lateral incisors served as the control. The teeth in the laser group received a total of ten doses of laser application: five doses from the buccal and five doses from the palatal side (two cervical, one middle, two apical) with an output power of 20 mW and a dose of 0.71 J /cm(2). Gingival crevicular fluid samples were obtained on the above-mentioned days, and the nitric oxide levels were analyzed. Bonferroni and repeated measures variant analysis tests were used for statistical analysis with the significance level set at p ≤ 0.05. The application of low-level laser therapy accelerated orthodontic tooth movement significantly; there were no statistically significant changes in the nitric oxide levels of the gingival crevicular fluid during orthodontic treatment.

Effects of maxillary molar intrusion with zygomatic anchorage on the stomatognathic system in anterior open bite patients.

The aim of this study was to evaluate the effects of intrusion of the maxillary posterior teeth with zygomatic anchorage on the dentofacial system, on electromyographic (EMG) activity of the masticatory muscles, and on vibration of the temporomandibular joint. The study sample consisted of 19 subjects (13 females, 6 males) with a mean age of 17.7 years. Lateral cephalometric and posteroanterior (PA) radiographs, EMG, and electrovibratographic (EVG) records were obtained before (T0) and after (T1) intrusion. Paired t- and Wilcoxon signed ranks tests were used for statistical evaluation. Maxillary molar intrusion of 3.37 ± 1.21 mm was obtained with a force of 400 g in an average period of 6.84 ± 1.64 months. At T1, all measurements showed that facial growth direction, ANB angle, convexity, and overjet were decreased (P < 0.05). SNB angle, facial depth, and overbite were significantly increased (P < 0.05). Upper lip-E plane distance was increased (P < 0.05). Evaluation of the PA radiographs showed that the right and left molar reference angles were unchanged. EMG and EVG analysis showed that the stomatognathic system at T0 was maintained at T1. Intrusion of the maxillary posterior teeth with zygomatic anchorage is an effective treatment alternative for anterior open bite correction.

Comparative evaluation of antimicrobial effects of Er:YAG, diode, and CO2 lasers on titanium discs: an experimental study.

PURPOSE: This study examined carbon dioxide (CO(2); 10,600 nm), diode (808 nm), and erbium (Er):yttrium-aluminum-garnet (YAG; 2,940 nm) laser applications on Staphylococcus aureus contaminated, sandblasted, large-grit, acid-etched surface titanium discs and performed a comparative evaluation of the obtained bactericidal effects and the applicability of these effects in clinical practice. MATERIALS AND METHODS: This study was carried out in 5 main groups: Er:YAG laser in very short pulse (VSP) emission mode, Er:YAG laser in short pulse (SP) emission mode, diode laser with a 320-nm fiber optic diode laser with an R24-B handpiece, and CO(2) laser. After laser irradiation, dilutions were spread on sheep blood agar plates and, after an incubation period of 24 hours, colony-forming units were counted and compared with the control group, and the bactericidal activity was assessed in relation to the colony counts. RESULTS: The CO(2) laser eliminated 100% of the bacteria at 6 W, 20 Hz, and a 10-ms exposure time/pulse with a 10-second application period (0.8-mm spot size). The continuous-wave diode laser eliminated 97% of the bacteria at 1 W using a 10-second application with a 320-µm optic fiber, 100% of the bacteria were killed with a 1-W, 10-second continuous-wave application with an R14-B handpiece. The Er:YAG laser eliminated 100% of the bacteria at 90 mJ and 10 Hz using a 10-second application in a superpulse mode (300-ms exposure time/pulse). The Er:YAG laser also eliminated 99% to 100% of the bacteria in VSP mode at 90 mJ and 10 Hz with a 10-second application. CONCLUSIONS: The results of this study show that a complete, or near complete, elimination of surface bacteria on titanium surfaces can be accomplished in vitro using a CO(2), diode, or Er:YAG laser as long as appropriate parameters are used.

Low-level laser therapy supported teeth extractions of two patients receiving IV zolendronate.

BRONJ (bisphosphonate-related osteonecrosis of jaws) is a frequently encountered disease, particularly in the maxillofacial region, and a consequence of bisphosphonate use. Treatment of BRONJ remains controversial, as efficiency of medical and surgical approaches as well as a combination of these methods with supportive treatments have not been clearly demonstrated in the literature. In recent years, laser usage alone or in combination with the main therapy methods, has become popular for the treatment of bisphosphonate-related osteo-necrosis of jaws. In this article, we present the successful management of two dental patients who had high potentials for BRONJ development as a result of chemo and radiotherapy combined with IV zoledronic acid application. Multiple consecutive teeth extractions followed with primary wound closure and LLLT applications were performed under high doses of antibiotics prophylaxis. Satisfactory wound healing in both the surrounding soft and hard tissues was achieved. LLLT application combined with atraumatic surgical interventions under antibiotics prophylaxis is a preferable approach in patients with a risk of BRONJ development. Adjunctive effect of LLLT in addition to careful infection control on preventing BRONJ was reported and concluded.

The effects of first premolar extractions on third molar angulations.

The purpose of this study was to determine the relationship between the inclinations of second and third molars during a two- to 2.5-year period in patients treated orthodontically both with and without premolar extractions. Records of 37 first premolar extraction patients and 33 nonextraction patients were examined. The pretreatment and posttreatment panoramic radiographs were analyzed. The angles were measured between the long axis of the third molar and the occlusal plane and between the long axis of the third molar and the long axis of the second molar. Changes in third molar angulations from pretreatment to posttreatment for two groups were compared by Mann-Whitney U-test. Statistical analysis revealed that mandibular third molars showed an improvement in angulation relative to the occlusal plane in the first premolar extraction group.

Low-level laser therapy supported surgical treatment of bisphosphonate related osteonecrosis of jaws: a retrospective analysis of 11 cases.

OBJECTIVE: The aim of this study is to evaluate and report on low-level laser therapy (LLLT) supported medical-surgical treatment outcomes of 11 patients with bisphosphonate related osteonecrosis of the jaws (BRONJ) lesions. BACKGROUND DATA: BRONJ is a severe clinical condition, which adversely affects patients' lives. Even though various treatment modalities have been proposed, the ideal approach still remains to be debated. LLLT stands out among supportive approaches because of its favorable effects on tissue healing. MATERIALS AND METHODS: Eleven patients diagnosed with Stage II or III lesions (American Association of Oral and Maxillofacial Surgeons [AAOMS] classification) were included in the study. All patients received LLLT applications during the postoperative period in addition to medical and surgical treatment. Laser applications covering the entirety of the surgical site were performed with GaAlAs diode laser with the following parameters: 808 nm wavelength, 0.5 W power, continuous wave, noncontact mode at 0.5-1 cm distance from the oral mucosa, spot size 0.28 cm(2) (R=6 mm), for 3 sec per point (10 sec per cm(2)), and energy density of 5 J/cm(2) (energy per point,1.4 J). RESULTS: Elimination of previously recorded symptoms and a stable mucosal closure was achieved in all patients. Primary healing was achieved in seven patients and secondary healing course was observed in four patients. Permanence of obtained positive outcomes was noted in follow-up periods. CONCLUSIONS: Treatment of advanced BRONJ lesions with a combination of antibiotic therapy, surgical removal of the lesion, and consecutive low-level diode laser applications provided favorable results in all patients. In consideration of our findings, it can be assumed that LLLT may serve as a safe and effective adjunct to medical-surgical treatment of BRONJ lesions.

Effect of low level laser therapy and zoledronate on the viability and ALP activity of Saos-2 cells.

A limited number of clinical studies indicate the supportive role of low level laser therapy (LLLT) on medical and/or surgical approaches carried out in treatment modalities for bisphosphonate related necrosis of jaws (BRONJ), the most common side effect of bisphosphonates used to inhibit bone resorption. The purpose of this study was to investigate the effects of LLLT on cell proliferation and alkaline phosphatase (ALP) activity of human osteoblast-like cells (Saos-2) treated with different doses of zoledronate, the most potent bisphosphonate. Saos-2 cells were treated with different concentrations of zoledronate and were irradiated with diode laser (wavelength 808 nm, 10 s, 0.25 or 0.50 W). Cell numbers and ALP activity of the cells were determined. LLLT mildly increased the proliferation rate or ALP activity, while zoledronate reduced both. When applied together, LLLT lessened the detrimental effects of zoledronate and improved cell function and/or proliferation. Based on the results of this study, it was concluded that LLLT has biostimulative effects on Saos-2 cells, even after treatment with zoledronate. LLLT may serve as a useful supportive method for BRONJ treatment through enhancement of healing by osteoblasts.

Effects of facemask treatment anchored with miniplates after alternate rapid maxillary expansions and constrictions; a pilot study.

OBJECTIVE: To describe the dentoskeletal and soft tissue effects of facemask treatment anchored with miniplates after alternate rapid maxillary expansions and constrictions (Alt-RAMEC) in maxillary retrusion patients. MATERIALS AND METHODS: The sample consisted of 15 patients with a mean skeletal age of 11.6 ± 1.59 years undergoing 8 weeks of Alt-RAMEC followed by maxillary protraction. Three hundred fifty to 400 g of force per side was applied to the facemask from the titanium miniplates inserted on the lateral nasal wall of the maxilla. Total treatment time was 9.9 ± 2.63 months. Treatment changes were evaluated cephalometrically and analyzed by means of the dependent t-test and the Wilcoxon signed rank test. RESULTS: The miniplates withstood the orthopedic forces exerted during the treatment. Cephalometric findings showed that the maxilla moved forward by 2 mm, with an 0.8° counterclockwise rotation and without maxillary incisor movement. The mandible moved slightly in a downward and backward direction (1.2°). The inclinations of the mandibular incisors decreased significantly (2°). Statistically significant increases were observed in the vertical dimension (1°-1.3°). Soft tissue changes were more marked in the upper lip and soft tissue pogonion than in the lower lip. CONCLUSIONS: This treatment approach can offer an advantage for correcting mild/moderate maxillary retrusion in Class III patients.

Effects of lidocaine with and without epinephrine on plasma epinephrine and lidocaine concentrations and hemodynamic values during third molar surgery.

Lidocaine with epinephrine is currently the most common local anesthetic agent used for impacted third molar surgery. The purpose of the present study was to define the adverse hemodynamic effects and plasma concentrations of lidocaine and epinephrine on 17 healthy patients during the impacted teeth operations. Arterial blood pressure (systolic blood pressure, diastolic blood pressure), heart rate, peripheral oxygen saturation range, and electrocardiography were measured by an automatic noninvasive pressure device and monitor. High-performance liquid chromatography was used to measure the changes of plasma concentrations of epinephrine and lidocaine from blood samples taken 5 different times during the operation. We concluded that lidocaine-epinephrine is effective local anesthetic and had no important adverse events in healthy patients during the third molar surgery.

Factors affecting the antibacterial effects of Nd:YAG laser in vivo.

BACKGROUND AND OBJECTIVES: One of the main advantages of laser surgery is it's bactericidal effect which reduces the risk of postoperative infections. Several study designs have been set to investigate this effect. Aim of this study was to research if the bactericidal effect of laser tool was affected from several factors in vitro studies. STUDY DESIGN/MATERIALS AND METHODS: To determinate and investigate the bactericidal effect of laser in an original model, alpha-hemolytic streptococcus, Bacterioides fragilis, Neisseria, Streptococcus salivarius, Staphylococcus aureus, and Candida albicans were prepared in 10(4), 10(6) and 10(8) inoculum and placed in Mueller-Hinton Broth which have five different proportions of sheep blood. Samples which exposed with various energy levels of Nd:YAG laser were spread on agar plates, and at the end of an incubation time the colonization counted comparatively. The lowest energy level without colonization was accepted as minimal bactericidal energy level. RESULTS: Highest minimum bactericidal energy level is used for alpha-hemolytic streptococcus and lowest values for neisseria. Bactericidal effect decreased on suspensions, of which population of microorganisms are high and hemoglobin concentration was high in the broth. CONCLUSIONS: These findings suggest that the Nd:YAG laser has a higher bactericidal effect when sheep blood is added to the media. Factors like population and type of bacteria in the irradiated suspension affect minimum bactericidal energy level.

Bifid mandibular condyle: a case report.

A case of left bifid mandibular condyle (BMC) is reported in a 36-year-old female. The patient had a history of trauma in childhood. From the radiological examination, the left condyle was seen to have two anterioposteriorly situated heads. BMC is an extremely rare condition, where the condyle is duplicated or lobulated. The literature on BMC is reviewed, and possible cause of trauma and consequences of the anomaly are discussed.