The effect of low-level laser therapy as an adjunct to periodontal surgery in the management of postoperative pain and wound healing: a systematic review and meta-analysis.

The meta-analysis and systematic review aimed to evaluate the effect of low-level laser therapy (LLLT) as an adjunct to periodontal surgery in the management of postoperative pain and wound healing. An electronic search in 4 databases (PubMed, Embase, Cochrane, and OpenGrey) was conducted for randomized clinical trials reporting the effectiveness of LLLT used as an adjunct to periodontal surgery to alleviate pain and accelerate wound healing compared with surgery alone. Finally, 13 studies were eligible and included. The results showed a significant difference of pain relief between groups at day 3 post-surgery, whereas no difference was found at day 7. Moreover, a significant reduction was observed in the mean analgesic intake during the first week in the LLLT group. On day 14, the adjunctive use of LLLT showed significantly faster re-epithelialization and better wound healing in palatal donor sites following free gingival graft procedures. Based on the results, LLLT used as an adjunct to periodontal surgery positively influenced postsurgical pain control. Low power (≤ 500 mW) combined with energy density ≥ 5 J/cm2 might be more appropriate for postoperative pain relief. Moreover, adjunctive LLLT to free gingival grafts could significantly accelerate wound healing of palate sites at early healing phase. Multicenter studies using different LLL parameters without postsurgical analgesics are needed to determine optimal laser settings.

Role of lasers as an adjunct to scaling and root planing in patients with type 2 diabetes mellitus: a systematic review.

The aim of the study was to assess the efficacy of adjunctive use of laser therapy (LT) alone or antimicrobial photodynamic therapy (aPDT) to improve clinical periodontal and HbA1c levels in patients with both chronic periodontitis (CP) and type 2 diabetes mellitus (T2DM). Electronic search of the MEDLINE, PubMed, EMBASE, Science Direct, and SCOPUS databases were combined with hand searching of articles published from 1975 up to and including March 2016 using relevant MeSH terms. Six studies were selected for this review. In these six studies, laser treatment was applied, after scaling and root planing (SRP), in two ways: Three studies used laser alone and three studies used laser with photosensitizer. All the six included studies reporting clinical periodontal and glycemic parameters showed that LT and aPDT were effective in the treatment of CP in T2DM subjects at follow-up. Two studies showed significantly better periodontal outcomes for LT as an adjunct to SRP as compared to SRP alone, whereas four studies showed comparable periodontal outcomes among adjunctive LT or aPDT with SRP. Two studies showed significant reduction of HbA1c levels in LT and aPDT as compared to SRP, whereas three studies showed comparable percentage levels at follow-up. It remains debatable whether LT or aPDT as adjunct to SRP is more effective as compared to SRP alone in the improvement of clinical periodontal and glycemic control in patients with both CP and T2DM, given that the scientific evidence is weak.

Effects of the GaAlAs diode laser (780 nm) on the periodontal tissues during orthodontic tooth movement in diabetes rats: histomorphological and immunohistochemical analysis.

The purposes of the present study are to assess the effects of the GaAlAs diode laser on the periodontal tissues and to investigate its action on the alveolar bone remodeling process during orthodontic tooth movement in normoglycemic and diabetic rats. Sixty adult male Wistar rats were divided into four groups of 15 rats: normoglycemic (N), diabetic (D), laser-normoglycemic (LN), and laser-diabetic (LD) rats. Diabetes mellitus was induced by a single intravenous injection of 40 mg/kg monohydrated alloxan. The orthodontically moved tooth underwent a force magnitude of 20 cN. The laser irradiation with a continuous emission of a 780-nm wavelength, an output power of 20 mW, and a fiber probe with a spot size of 0.04 cm in diameter and an area of 0.00126 cm2 were used. Moreover, an energy density of 640 J/cm2 was applied in an exposition time of 40 s. Histomorphological and immunohistochemical analysis was performed. The photobiomodulation (PBM) strongly stimulated the periodontal tissue response, establishing mainly the balance between the bone formation and resorption. Intense inflammatory cell infiltration and extensive loss of bone tissue were mainly found in the D group from 14 days. The number of osteopontin-positive osteocytes was significantly greater in the LN group, followed by the LD, especially at 7 and 14 days, whereas osteoprotegerin-positive osteoblasts were significantly higher in the LN and LD groups than in the N and D groups, respectively, in all periods. The PBM strongly stimulated the alveolar bone remodeling and favored the continuous reorganization of the soft periodontal tissues, leading to the maintenance and integrity of the periodontal microstructure under orthodontic force, especially in uncontrolled diabetic rats.

Selective photoantisepsis.

BACKGROUND AND OBJECTIVE: Selective killing of pathogens by laser is possible due to the difference in absorption of photon energy by pathogens and host tissues. The optical properties of pathogenic microorganisms are used along with the known optical properties of soft tissues in calculations of the laser-induced thermal response of pathogen colonies embedded in a tissue model. The objective is to define the laser parameters that optimize pathogen destruction and depth of the bactericidal effect. MATERIALS AND METHODS: The virtual periodontium is a computational model of the optical and time-dependent thermal properties of infected periodontal tissues. The model simulates the periodontal procedure: Laser Sulcular Debridement.1 Virtual pathogen colonies are placed at different depths in the virtual periodontium to determine the depth for effective bactericidal effects given various laser parameters (wavelength, peak power, pulse duration, scan rate, fluence rate) and differences in pathogen sensitivities. RESULTS: Accumulated background heat from multiple passes increases the depth of the bactericidal effect. In visible and near-IR wavelengths the large difference in absorption between normal soft tissue and Porphyromonas gingivalis (Pg) and Prevotella intermedia (Pi) results in selective destruction. Diode laser (810 nm) efficacy and depth of the bactericidal effect are variable and dependent on hemin availability. Both pulsed-Nd:YAG and the 810 nm diode lasers achieve a 2-3 mm deep damage zone for pigmented Pg and Pi in soft tissue without surface damage (selective photoantisepsis). The model predicts no selectivity for the Er:YAG laser (2,940 nm). Depth of the bactericidal effect is highly dependent on pathogen absorption coefficient. Highly sensitive pathogens may be destroyed as deep as 5-6 mm in soft tissue. Short pulse durations enable confinement of the thermal event to the target. Temporal selectivity is achieved by adjusting pulse duration based on target size. CONCLUSION: The scatter-limited phototherapy model of the infected periodontium is applied to develop a proper dosimetry for selective photoantisepsis. Dosimetry planning is essential to the development of a new treatment modality. Lasers Surg. Med. 48:763-773, 2016. © 2016 Wiley Periodicals, Inc.

Histopathologic and Histomorphometric Analysis of Irradiation Injury in Bone and the Surrounding Soft Tissues of the Jaws.

PURPOSE: Surgery of irradiated tissue has an increased complication rate because of the development of hypovascular, hypocellular, and hypoxic tissue. This study was undertaken to perform histopathologic and histomorphometric analyses of irradiation tissue injury in bone and the surrounding soft tissues. MATERIAL AND METHODS: The histopathologic findings of 40 human mandibular bones and the surrounding soft tissue specimens obtained from different patients who underwent surgical procedures for treatment of osteoradionecrosis of the jaws were reviewed. RESULTS: Histopathologic examination showed 7 processes in the following order of appearance: hyperemia, endarteritis, thrombosis, cell loss, hypovascularity, increase of fat in the bone marrow cavity, and fibrosis. Histomorphometric analysis showed significant hypocellularity (P = .007), hypovascularity (P < .001), and fibrosis (P < .001) in irradiated specimens compared with control specimens. CONCLUSION: These results showed that radiation injuries affect the bone and surrounding soft tissues. However, the irradiation-induced injuries, such as cellular loss (hypocellularity) and fibrosis, were more expressive in bone tissue than in the surrounding soft tissues.

Controlling periodontal bone levels with multiple LED irradiations.

Because a single exposure to light-emitting diode (LED) irradiation at 660 nm only demonstrated a 3-day biostimulatory effect in recovering periodontal bone level (PBL), this study sought to evaluate whether the periodontal effect could be extended through the use of multiple LED irradiations. Experimental periodontitis was developed unilaterally in 48 Sprague-Dawley rats after the placement of a silk ligature plus Porphyromonas gingivalis lipopolysaccharide injections. The animals were divided into four groups (no irradiation, a single irradiation, or two or three irradiations per week) and exposed to LED light irradiation at a wavelength of 660 ± 25 nm and energy density of 10 J/cm(2) after debridement and detoxification. The animals were euthanized after 7 or 14 days, and the effect of irradiation was evaluated using micro-computed tomography and histology. By day 7, PBL was significantly reduced (p < 0.05), with significantly reduced inflammation (p < 0.05) and gingival hyperplasia (p < 0.001), in the animals receiving three irradiations per week. At day 14, the reduction in gingival hyperplasia was still significant (p < 0.05), and collagen matrix deposition and realignment appeared to be accelerated in the animals receiving three irradiations per week, despite a lack of significant difference in PBL. The treatment regimen receiving three LED light irradiations per week apparently extended the effects in reducing PBL and inflammation to 7 days. The inclusion of additional inflammation control measures or the addition of bioactive signals to mediate the repairing process is necessary to maintain long-term periodontal stability.

The effect of blue light on periodontal biofilm growth in vitro.

We have previously shown that blue light eliminates the black-pigmented oral bacteria Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, and Prevotella melaninogenica. In the present study, the in vitro photosensitivity of the above black-pigmented microorganisms and four Fusobacteria species (Fusobacterium nucleatum ss. nucleatum, F. nucleatum ss. vincentii, F. nucleatum ss. polymorphum, Fusobacterium periodonticum) was investigated in pure cultures and human dental plaque suspensions. We also tested the hypothesis that phototargeting the above eight key periodontopathogens in plaque-derived biofilms in vitro would control growth within the dental biofilm environment. Cultures of the eight bacteria were exposed to blue light at 455 nm with power density of 80 mW/cm2 and energy fluence of 4.8 J/cm2. High-performance liquid chromatography (HPLC) analysis of bacteria was performed to demonstrate the presence and amounts of porphyrin molecules within microorganisms. Suspensions of human dental plaque bacteria were also exposed once to blue light at 455 nm with power density of 50 mW/cm2 and energy fluence of 12 J/cm2. Microbial biofilms developed from the same plaque were exposed to 455 nm blue light at 50 mW/cm2 once daily for 4 min (12 J/cm2) over a period of 3 days (4 exposures) in order to investigate the cumulative action of phototherapy on the eight photosensitive pathogens as well as on biofilm growth. Bacterial growth was evaluated using the colony-forming unit (CFU) assay. The selective phototargeting of pathogens was studied using whole genomic probes in the checkerboard DNA-DNA format. In cultures, all eight species showed significant growth reduction (p < 0.05). HPLC demonstrated various porphyrin patterns and amounts of porphyrins in bacteria. Following phototherapy, the mean survival fractions were reduced by 28.5 and 48.2% in plaque suspensions and biofilms, respectively, (p < 0.05). DNA probe analysis showed significant reduction in relative abundances of the eight bacteria as a group in plaque suspensions and biofilms. The cumulative blue light treatment suppressed biofilm growth in vitro. This may introduce a new avenue of prophylactic treatment for periodontal diseases.

Periodontal care in patients undergoing radiotherapy for head and neck cancer.

PURPOSE: The aim of this study was to evaluate periodontal changes after periodontal treatment and control in patients with malignant tumors of the upper aerodigestive tract who were submitted to radiotherapy with or without chemotherapy. METHODS: We included all patients attending the Oncology Clinic of the Federal University of Minas Gerais, School of Dentistry. Clinical periodontal parameters obtained by a single calibrated examiner were evaluated at baseline, 10 days after radiotherapy, and 180 days after radiotherapy. Patients were grouped into healthy or periodontally diseased individuals. All patients received oral hygiene instructions, and the diseased patients received periodontal therapy at baseline. Comparisons between the groups were performed via the McNemar and Wilcoxon tests using SPSS v. 17.0. RESULTS: A total of 28 patients were examined at baseline, of which 27 were examined 10 days after radiotherapy and 25 were examined 180 days after radiotherapy. The prevalence of periodontal disease at baseline was 67.9 % and did not decrease over time (p = 1.0). There was a significant reduction in probing depth (PD), plaque index (PI), and bleeding on probing between baseline and follow-up, which was not observed in the attachment level (AL). CONCLUSIONS: Periodontal therapy was effective in reducing PI and improving periodontal status, as evidenced by the decreases in PD and the maintenance of AL.

Histological examination of experimentally infected root canals after preparation by Er:YAG laser irradiation.

The influence of Er:YAG laser irradiation on periodontal tissues along the root surface and apical region during root canal preparation was histologically evaluated using experimentally infected root canals of rats. Eighty experimentally mesial infected root canals of mandibular first molars in rats were divided into four groups. In three groups, root canals were irradiated using an Er:YAG laser at 2 Hz with 34, 68, or 102 mJ/pulse for 30 s. Non-irradiated canals served as controls. The influence of laser irradiation on periodontal tissues along the root surface and apical area was evaluated histologically under light microscopy at 0 (immediately after), 1, 2, 4, and 8 weeks after irradiation. At all periods, no inflammation or resorption on the root surfaces caused by laser irradiation was observed in any cases in the control or 34 mJ/pulse-irradiated groups. However, mild to severe inflammation with resorption of root surfaces was observed in some cases in the 68- and 102-mJ/pulse-irradiated groups. No significant difference was apparent between control and laser-irradiated groups at the apical area for all experimental periods (p > 0.05). These results suggest that thermal influences on periodontal tissues of experimentally infected root canals during root canal preparation by Er:YAG laser irradiation are minimal if appropriate parameters are selected. Er:YAG laser irradiation is thus a potential therapy for human infected root canals.

Effect of low-level laser therapy on the healing process after tooth replantation: a histomorphometrical and immunohistochemical analysis.

Success of tooth replantation is limited because part of the replanted tooth is lost because of progressive root resorption. This study used histomorphometry and immunohistochemistry to evaluate the effect of low-level laser therapy (LLLT) on the healing process of rat teeth replanted after different extra-oral periods, simulating immediate and delayed replantation. Sixty Wistar rats (Rattus norvegicus albinus) had their maxillary right incisors extracted and randomly assigned to six groups (n = 10): C4, C30 and C45, in which the teeth were replanted 4 min (immediate), 30 min (delayed) and 45 min (delayed) after extraction, respectively, and L4, L30 and L45, in which the teeth were replanted after the same extra-alveolar times, but the root surfaces and the alveolar wounds were irradiated with a gallium-aluminum-arsenate (GaAlAs) diode laser before replantation. The animals were sacrificed after 60 days. The anatomic pieces containing the replanted teeth were obtained and processed for either histomorphometrical analysis under optical microscopy or immunohistochemical expression of receptor activator of nuclear factor Kappa-B (RANK), and its ligand (RANKL), osteoprotegerin (OPG) and tartrate-resistant acid phosphatase (TRAP) proteins. Areas of external replacement and inflammatory root resorption were observed in all groups, without statistically significant differences (P > 0.05). Ankylosis was more frequent in L30 than in C30 (P < 0.05). RANKL immunostaining predominated over RANK and OPG immunostaining in both groups with immediate tooth replantation (P < 0.05). For the 45-min extra-alveolar time, however, there was greater evidence of RANK immunostaining compared to RANKL for both control and laser-treated groups (P < 0.05). Positive TRAP immunostaining predominated in L4 and L30 (P < 0.05). In conclusion, under the tested conditions, the treatment of the root surface and the alveolar wound with LLLT did not improve the healing process after immediate and delayed tooth replantation in rats.

Low-level laser irradiation facilitates fibronectin and collagen type I turnover during tooth movement in rats.

The aim of this study was to investigate the effects of low-level laser (LLL) irradiation on the turnover of fibronectin and collagen type I in periodontal tissue during tooth movement in rats by immunohistochemistry. Thirty male Sprague-Dawley rats aged 15 weeks were assigned to either an experimental group (n = 15) that underwent LLL irradiation during tooth movement, or a control group (n = 15). In the experimental group, the gallium-aluminum-arsenide (Ga-Al-As) diode LLL (wavelength 808 nm; output 96 mW) was used to irradiate three areas on both the palatal side and the labial side of the maxillary incisor. The radiation was administered by the contact method for 10 s at 0.83 J/cm(2) energy dose, once a day for 7 days. Total energy dose over the complete schedule was 34.86 J/cm(2). The animals were killed on days 1, 3, 7, 14 and 21. There was no difference between the two groups in the amount of tooth movement. The immunohistochemistry results showed that the expression of fibronectin and collagen type I in the experimental group had significantly increased from day 1, with a more even distribution than in the control group, and that this difference was maintained until the end of the experiment. These results suggest that LLL irradiation facilitates the reorganization of the connective tissues during tooth movement in rats.

ODONTOLOGICAL EFFECTS OF IONIZING RADIATION (review). / ODONTOLOGIChNI EFEKTY IONIZUIuChOGO VYPROMINIuVANNIa (ogliad).

BACKGROUND: Odontological effects of ionizing radiation (IR) as a result of radiotherapy, the consequences of accidents at nuclear power plants and industry, individual occupational exposure, etc. deserve significant attention interns of radiation medicine and radiation safety. OBJECTIVE: to analyze and summarize clinical and experimental data on the odontological radiation effects. OBJECT: the pathological changes in the hard tissues of teeth, pulp, periodontium, mucousmembranes of the mouth and jaws due to exposure to IR. METHOD: search in the PubMed / MEDLINE, Google Scholarabstract medical and biological databases, scientific libraries of the relevant sources of scientific information. RESULTS: Radiobiological effects of IR due to its direct and indirect action are manifested throughout the period ofodontogenesis and formation of the facial skeleton. Experimental and clinical data (in children and adults) indicatethe increased risk of dental caries, reduction of pain threshold and vascularization of tooth pulp along with its fibrosis and atrophy, periodontal dysfunction, which predispose to a high probability of tooth loss. Abnormalities in theactivity of osteoblasts and cementoblasts of dental periosteum and osteoblasts of alveolar process in combinationwith circulatory disorders due to endothelial cell death, hyalinization, thrombosis and vascular obliteration increasethe risk of jaw osteoradionecrosis. Children who have undergone a prenatal exposure to IR as a result of theChornobyl NPP accident have a premature change of teeth. Deterioration of periodontal tissues and early development of acute and complicated dental caries are typical for children and adults affected by the Chornobyl disaster. CONCLUSIONS: Summarized data on the effects of radiation exposure under different conditions on teeth primordia(i.e. immature teeth), their formation and eruption in experimental and clinical settings, as well as on the odontological radiation effects in adults are summarized. Condition of the teeth in the Chornobyl NPP accident survivorsis described. Understanding and taking into account the radiobiological odontological effects is necessary in thelight of planning, preparing, and conducting local radiation therapy and developing the standards of radiation safety and measures to protect professionals and the public in the event of possible radiation accidents at the nuclearpower plants and industry facilities.

Effects of the photobiomodulation using different energy densities on the periodontal tissues under orthodontic force in rats with type 2 diabetes mellitus.

To evaluate the impact of the GaAlAs diode laser with energy densities of 160 J/cm2, 320 J/cm2, and 640 J/cm2 on the periodontal tissues under continuous orthodontic force application and on the rate of orthodontic tooth movement in rats with type-2 diabetes mellitus. The intensity of primary alveolar bone formation was also investigated through the immune-positive osteocytes for OPN antibody. Forty adult male Wistar rats were divided into eight groups of 5 rats: normoglycemic (N), 160 J-laser-normoglycemic (160 J-LN), 320 J-laser-normoglycemic (320 J-LN), 640 J-laser-normoglycemic (640 J-LN), diabetic (D), 160 J-laser-diabetic (160 J-LD), 320 J-laser-diabetic (320 J-LD), and 640 J-laser-diabetic (640 J-LD) rats. Diabetes mellitus was induced by a single intravenous injection of 40 mg/kg monohydrated-alloxan. An orthodontic force magnitude of 20cN was applied. The laser parameters were continuous emission of 780-nm wavelength, output power of 20mW, and fiber probe with a spot size of 0.04 cm in diameter. Radiographic, histomorphological, and immunohistochemical analysis were performed after a period of 21 days. The photobiomodulation using the energy density of 640 J/cm2 strongly stimulated the alveolar bone formation and contributed the reorganization of the soft periodontal tissues, followed by the 320 J/cm2. Extensive alveolar bone loss, intense infiltration of inflammatory cells, and degradation of the PDJ tissue were mainly found in the D and 160 J-LD groups. The rate of orthodontic tooth movement was represented by the interdental distance between the cementoenamel junctions of the right mandibular first and second molars . This distance was larger in the diabetic groups (D: 39.98±1.97, 160 J-LD: 34.84±6.01, 320 J-LD: 29.82±1.73, and 640 J-LD: 35.47±4.56) than in the normoglycemic groups (N: 21.13±1.19; 160 J-LN: 22.69±0.72, 320 J-LN: 22.28±0.78, and 640 J-LN: 24.56±2.11). The number of osteopontin-positive osteocytes was significantly greater in the 640 J-LD (14.72 ± 0.82; p < 0.01) and 640 J-LN (13.62 ± 1.33; p < 0.05) groups than with D (9.82 ± 1.17) and 160 J-LD (9.77 ± 1.10) groups. Therefore, the energy density of 640 J/cm2 provided the best maintenance and integrity of the periodontal tissue microarchitecture under continuous orthodontic force when compared with the other dosages, mainly in the uncontrolled diabetic rats. The interdental distance was greater in the D and 160 J-LD groups due to presence of severe periodontitis caused by diabetes plus the mechanical stress generated by continuous orthodontic forces, implying, thus, an insufficient biostimulatory effect for the dosage of 160 J/cm2.

[Treatment decision for periodontal patients with history of cancer].

Radiotherapy and chemotherapy might change the healing process of periodontal disease by reducing there storability of the periodontal tissues, leading the increase of attachment lose and alveolar bone absorption. The primary periodontal lesions could be aggravated. Therefore, oral screening should be conducted before periodontal treatment, in order to eliminate dental focal infection, to stabilize the oral environment and to prevent and reduce complications after cancer treatment. The patient's general situation should be evaluated before the periodontal treatment too, so as to ensure the patient could tolerate the radiotherapy and chemotherapy in the short interval between diagnosis and treatment of cancer. The periodontal treatment should be more conservative than normal periodontal patients. The indication for tooth extraction in these patients should be less conservative.

Radiation therapy of the oral cavity: sequelae and management, part 1.

This is the first article in a two-part series dealing with the effects and manifestations in the oral cavity of radiation therapy of head and neck tumors. In this section, oral mucous membranes, taste buds, edema and trismus, diet, salivary glands, bone, periodontium, teeth, and composition of oral flora are discussed. Dental management of the dentulous patient is then approached; criteria for preradiation extraction are delineated. In the next issue of Head & Neck Surgery, the final article in this series will discuss preradiation and postradiation extractions and will elaborate on the dental management (fluoride treatments, follow-up, and restorative care) of the dentulous patient. Dental management of the edentulous patient will also be presented.

Severe progressive periodontal destruction due to radiation tissue injury.

Cancer radiotherapy to the head and neck region results in short- and long-term radiation tissue injuries. Radiation bone injury is a long-term manifestation which could progress to osteoradionecrosis. A case of radiation tissue injury to the periodontium is presented. The possible pathogenesis of these events is described as they relate to the sequential radiographic changes observed over a period of 6 years until the involved teeth were exfoliated. The post-irradiation management of the teeth with advancing periodontal disease in the path of irradiation was by conservative means, including good personal oral hygiene care, scaling and root planing, periodic chlorhexidine irrigation, and topical fluoride application.

Periodontal changes in patients undergoing radiotherapy.

BACKGROUND: The purpose of this study was to evaluate changes in the periodontium in patients who received head and neck radiation therapy. METHODS: Periodontal clinical parameters (probing depth, clinical attachment level, gingival recession, plaque index, and bleeding on probing) were assessed on 27 patients before and 6 to 8 months following radiation therapy in the head and neck area. RESULTS: The greatest changes occurred in clinical attachment level: overall, 70.3% of the patients showed a loss, with 92% evincing loss in the mandible. Attachment loss was directly related to the field of radiation and was greater when the jaws were actually included in the irradiated area. CONCLUSION: Periodontal status should be evaluated prior to and following radiation therapy in the oral-maxillary-facial region to help ensure that periodontal health is maintained in oncology patients.

Periodontium destruction associated with oncology therapy. Five case reports.

Radiation treatment to the head and neck and cytotoxic chemotherapy can produce deleterious side effects to the periodontium that are generally transient in nature, reversible, and do not result in permanently visible defects. However, combinations of the malignant disease itself, the direct and indirect effects of medical therapy and associated oral infections, along with local trauma can lead to periodontal tissue destruction with resulting permanent architectural defects. Five case reports illustrate destructive alterations of the periodontium that were associated with oncology therapy. Proposed guidelines for periodontal treatment of compromised individuals undergoing oncology therapies are suggested.

Heat generation in hydroxyapatite-coated implants as a result of CO2 laser application.

Previous studies have demonstrated that heat may induce bone resorption and minimize the regenerative capacity of bone. This finding is of potential clinical importance because the carbon dioxide laser may often be used to surgically expose dental implants. However, little is known about the actual amount of heat generated at the implant-bone interface. This experiment measured heat generation on the surface of dental implants exposed to the carbon dioxide laser. A total of 90 trials were performed. A complete factorial (3 x 3 x 2) experimental design was used to evaluate the interactions among laser wattage output (4, 8, and 15 watts), duration of exposure time (1, 5, or 15 seconds) and variations in emission conditions (pulsed or continuous laser mode). Linear increases in temperature to temperatures greater than 50 degrees C were observed with increases in wattage output or duration of exposure time. The pulse mode generated significantly less heat. The results of this study suggest that caution should be used when using the carbon dioxide laser for second stage dental implant surgery.

Investigating the range of surgical effects on soft tissue produced by a carbon dioxide laser.

The authors investigated the surgical and collateral effects on soft tissue of a carbon dioxide laser emitting at 9.3 micrometers. Specifically, incision widths and depths as well as effectiveness were studied. Three different laser modes were investigated: gated continuous wave, or Cw, Superpulse and OptiPulse (Medical Optics). Incision depths correlated positively with average power; higher powers produced deeper incisions. The gated Cw mode quickly produced wide, deep incisions; Superpulse achieved narrower, deep incisions; OptiPulse caused very narrow, shallow incisions. Collateral damage to adjacent tissues was reduced by a factor of about 2 using Superpulse, and by a factor of 10 using OptiPulse. A wide range of effects is achieved in soft tissue, depending on the laser parameter combination used.