Esthetic Treatment of Gingival Melanin Hyperpigmentation With Er:YAG Laser: Short-Term Clinical Observations and Patient Follow-Up

Relationship of skin complexion with gingival tissue color and hyperpigmentation. A multi-ethnic comparative study

BACKGROUND AND OBJECTIVE

The most frequently seen intra-oral soft tissue is the gingiva. Most often, it is seen as coral-pink tissue that surrounds the neck of the teeth. Gingiva that encircles the tooth necks and covers the alveolar processes of the jaws is an intra-oral tissue that exhibits biomimetic features. The wide range of colors of the gingiva depends on the configuration of gingival vascularity, the degree of epithelial cornification, level of melanogenesis, and the depth of epithelialization. However, the color of the gingiva varies depending on the degree of melanin pigmentation. The current study aimed to identify the different distribution patterns of gingival color and determine the correlation between skin color, gender, and geographical area of origin.

MATERIALS AND METHODS

A total of 839 subjects were involved in the study where the gingival color and skin tone were measured using the Dummett-Gupta Oral pigmentation Index (DOPI) combined with VITA VMK MASTER and skin shade method developed by Revlon (USA) and L'Oreal (France) for makeup foundation shades. One investigator was calibrated for the examination of the colors after being tested for normal color vision and color aptitude using the line test.

RESULTS

A significant association was found between skin color and gingival pigmentation (χ2 value (6) = 114.48; P = 0.001). It was also found that females (67.1%) significantly had darker gingiva than males (58.3%). The study statistics display that location of the individual was also statistically associated with melanin pigmentation of the gingiva (χ2 value (57) = 559.33; P = 0.001).

CONCLUSION

The study concluded that gender, skin color, and individual location are significantly associated with gingival melanin pigmentation.

Assessment of clinical outcomes and patient response to gingival depigmentation using a scalpel, ceramic bur, and diode laser 980 nm

OBJECTIVE

This research compares the clinical outcomes of gingival depigmentation procedures with conventional scalpel, ceramic trimmer bur, and diode laser techniques.

MATERIALS AND METHODS

Twenty-four individuals with physiologic gingival hyperpigmentation received random allocation to one of three treatment groups: scalpel, ceramic bur, or diode laser. Pain score, operation time, bleeding index, degree of epithelialization, wound healing, Dummett-Gupta Oral Pigmentation Index (DOPI), and Takashi Index score changes were all investigated at different time points.

RESULTS

At 12-h follow-up, significant variations in pain scores were seen between the laser and scalpel groups (p = 0.003) but not between the laser and ceramic bur groups. The diode laser group completed the procedure significantly quicker than the scalpel and ceramic bur groups (p = 0.004 and p = 0.001, respectively). The ceramic trimmer bur and diode laser groups showed significantly less bleeding tendency than the scalpel group. Wound healing and the degree of epithelialization were similar in all groups. DOPI and Takashi indices significantly decreased compared to baseline in all groups, with no significant difference recorded between all groups.

CONCLUSION

While diode lasers are a safe and effective treatment option for gingival hyperpigmentation, providing optimal aesthetics with reduced discomfort to patients, a ceramic trimmer bur can also be used as a simple and affordable alternative to a laser in gingival depigmentation procedures.

CLINICAL RELEVANCE

Gingival hyperpigmentation is a major aesthetic issue for many individuals. Laser and ceramic trimmer bur treatments produce equivalent aesthetic outcomes for gingival hyperpigmentation.

Histological evaluation of mouse tongue incisions after Er:YAG laser surgery with different pulse energies versus after conventional scalpel surgery

PURPOSE

To identify the surgical instrument that allows for optimal healing of tongue incisions.

METHODS

An Er:YAG laser was compared with different pulse energies to a conventional scalpel for the incision of mouse tongue tissues. Mice were sacrificed through cervical dislocation at 24, 48, and 72 h postoperatively, followed by extraction of their tongues for incision experiments. The healing of the incisions and expression of inflammation- and pain-related factors in the tongues were compared between the surgical procedure groups.

RESULTS

In laser-treated mice, tongue incisions healed the fastest when the laser output energy was 60 MJ per pulse. Macrophage chemotaxis toward the incisional area was triggered on the first postoperative day for the 60-MJ group, while the time for macrophage chemotaxis to the surgical area was later in the 80-MJ group. Tumor necrosis factor-alpha expression increased and then decreased in the 80-MJ group; however, it gradually decreased in the 60-MJ and conventional scalpel groups. Prostaglandin E2 expression increased and then decreased in the 80-MJ and conventional scalpel groups but gradually decreased in the 60-MJ group. The expression of transforming growth factor beta 1 gradually decreased in the 60-MJ and 80-MJ groups but gradually increased in the conventional scalpel group.

CONCLUSION

Compared with surgical procedures using conventional scalpels, those using an Er:YAG laser with appropriate pulse energies can inhibit inflammation in the incisional area and promote incision healing. The use of an Er:YAG laser with appropriate pulse energies can alleviate intraoperative and postoperative pain in the incisional area.

Comparison of Er,Cr:YSGG laser and diode laser in the treatment of gingival melanin pigmentation: a randomized clinical trial

This investigation has aimed to compare the efficiency of clinical depigmentation and repigmentation rate of erbium chromium-doped: yttrium, scandium, gallium, garnet (Er,Cr:YSGG) and diode lasers during a 1-year follow-up and to evaluate patient satisfaction. Twenty-two participants were divided into Er,Cr:YSGG laser and diode laser groups using computer-aided randomization. Dummett Oral Pigmentation Index (DOPI) and photographic assessment with ImageJ Software version 10.2 were performed at the preoperative period and postoperative 1st month, 6th month, and 12th month. Moreover, the study assessed intra- and postoperative intensities of pain and postoperative patient aesthetic satisfaction using the Visual Analog Scale in both groups. The median values of DOPI did not differ statistically between the groups according to time (p > 0.05). In the Er,Cr:YSGG group, the extension of repigmentation was less as compared to the diode group at 1-year follow-up (p = 0.045). In the Er,Cr:YSGG group, the patients felt less intraoperative pain and discomfort compared to the diode group (p = 0.007). No significant differences were found between the two groups in terms of patient aesthetic satisfaction at the 1st and 12th months. The findings indicate that diode and Er,Cr:YSGG lasers can be used safely in depigmentation treatment, while the Er,Cr:YSGG laser has been shown to have superiorities in pain management and patient comfort parameters. Clinical Trial No.: NCT05304624.

Assessment of gingival thickness in multi-ethnic subjects with different gingival pigmentation levels

AIM

Assessment of the thickness of gingival tissues using the probe visibility test is regarded as the method of choice during routine examinations. However, the probe visibility test has not been validated for patients with gingival pigmentation and its accuracy in populations with physiological gingival pigmentation is yet unknown. This study aims to evaluate different methods for the clinical assessment of gingival thickness in participants with varying levels of gingival pigmentation.

MATERIALS AND METHODS

Buccal mucosa of the maxillary right central incisor teeth of 171 participants was evaluated using four methods, which were direct measurements using calliper, transgingival probing method using an endodontic probe, and probe visibility method using Colorvue biotype probe (CBP) and UNC-15 probe. The pigmentation of the gingiva was assessed using the Dummett-Gupta oral pigmentation lesion index.

RESULTS

The average gingival thickness of the selected population was 1.22 ± 0.38 mm with a distribution of 70% thick and 30% thin gingiva. Transgingival and calliper methods showed good agreement and significant correlation (r = 0.229; p = .003). Visual assessment using CBP and UNC-15 probe showed poor agreement with the direct measurement methods. Gingival pigmentation significantly affected the probe visibility assessment, reducing the visibility of both the CBP (odds ratio [OR] = 4.00; 95% confidence interval [CI], 1.83-8.74) and UNC-15 probe (OR = 1.84; 95% CI, 1.05-3.23) while controlling for thickness of the gingiva.

CONCLUSION

The probe visibility method using either CBP or the UNC-15 probe is affected by the degree of gingival pigmentation. Direct measurements using either a calliper or transgingival probing are recommended as methods to measure the gingival thickness in populations with gingival pigmentation.

Transepithelial Gingival Depigmentation Using a New Protocol with Q-Switched Nd:YAG: An In Vivo Observational Study

Gingival melanin hyperpigmentation is a para-physiological condition that may have a negative impact on smile esthetics. In the present study, the use of the Q-Switched Nd:YAG laser, according to a defined protocol, was proposed to treat Gingival Melanin Hyperpigmentation with a transepithelial approach. A total of 10 Patients with different grades of gingival hyperpigmentation were treated with Q-Switched Nd:YAG in one to four laser sessions without local anesthesia. The grade of depigmentation was evaluated by comparing Oral Pigmentation Index (OPI) and Melanin Pigmentation Index (MPI) at baseline and three weeks after the laser session. Additionally, oral discomfort rated by the Numeric Rating Scale (NRS) was recorded one, three, and five days after the procedure. Complete depigmentation was achieved in all cases. Patients reported no-little discomfort (NRS 0 to 3) during the laser session that lasted a maximum of five days. No major complications were reported, and no recurrences were observed at least after one year of follow-up. In addition, patients were available to be re-treated if necessary. These findings suggested that the Q-Switched Nd:YAG could be an effective and well-tolerated approach in the treatment of gingival melanin hyperpigmentation.

Long-Term Esthetically Depigmented Gingiva in a Short Operative Duration, Using Two Modes of 940 nm Diode Lasers-A Randomized Clinical Trial

AIM

This study aims to compare the effectiveness of the two modes of 940 nm diode lasers on gingival depigmentation.

METHODS

Twenty patients (11 females and 9 males) participated in this study; they were free of any systemic or local condition and randomly assembled into two groups: continuous wave (CW) and pulsed groups, in contact modes. The diode laser was of 940 nm wavelength and 1-2 W irradiation power for the two modes in all cases. A single session of irradiation was applied to the facial gingivae of the upper and lower anterior segments. Photographs were taken preoperatively and postoperatively for all patients, and a questionnaire and follow-up were carried out for the next four weeks and after three years.

RESULTS

The intraoperative duration of both modes was considerably short, with a short chair time subsequently. A statistically significant decrease in the intensity of pain, discomfort, and bleeding (p ≤ 0.05) was noticed during the first week of follow-up within each group. Nonetheless, the two groups showed a close pattern of decline with no statistically significant differences between them. It was also clear that pain and discomfort were strongly correlated with each other within each group, and the correlation was statistically significant. On the other hand, carbonization was minimal in a few cases treated with CW mode but still not statistically significant. Finally, although the gingival pigmentation index (GPI) differences were not statistically significant between the two groups, they were significant within each group.

CONCLUSIONS

The diode laser (940 nm) offered an effective and safe modality, providing an optimal aesthetic result that can meet patient satisfaction with minimal pain, bleeding, discomfort, intraoperative time, and the possibility of recurrence in the treatment of gingival hyperpigmentation.

Novel flapless esthetic procedure for the elimination of extended gingival metal tattoos adjacent to prosthetic teeth: Er:YAG laser micro-keyhole surgery

PURPOSE

This article describes a novel, minimally invasive procedure called Er:YAG laser micro-keyhole surgery (EL-MIKS) that removes metal or amalgam tattoos in the gingiva adjacent to prosthetic teeth without gingival deformity and recession. We aimed to evaluate the clinical efficacy of EL-MIKS for removing metal tattoos and present its long-term treatment outcomes.

METHODS

The EL-MIKS procedure consists of several steps that are all performed under a microscope. First, a micro-keyhole (1-2 mm diameter) was prepared using an Er:YAG laser in the center of the metal pigmentation. The connective tissue was evaporated in the deep layer, where metal debris was deposited. Second, within the accessible range, the irradiation angle was changed in various directions to ablate the metal pieces and discolored connective tissue without enlarging the keyhole. Finally, after blood filled the space created by the tissue evaporation, the surface of the blood clot at the entrance of the micro-keyhole was thermally coagulated with defocus laser irradiation. Pigmentation that could not be successfully removed from a single micro-keyhole was treated by forming new micro-keyholes at a distance of 3 mm or more from each previously created hole. Depigmentation over an extended area was completed over a few sessions every 4 weeks without gingival recession after surgery.

CONCLUSIONS

EL-MIKS, a novel depigmentation technique, was able to successfully remove an extended area of metal tattoos in the gingiva using a simpler, easier, and less invasive procedure than conventional periodontal plastic surgery. Esthetic restoration was successfully achieved without postoperative alteration of the gingival contour.

Gingival depigmentation with diode and Er,Cr:YSGG laser: evaluating re-pigmentation rate and patient perceptions

OBJECTIVE

To evaluate the efficiency of depigmentation, patient perceptions, and the recurrence rates of physiological gingival pigments during a 2-year follow-up after ablative depigmentation using two laser wavelengths: diode 940 nm and Er,Cr:YSGG 2780 nm.

MATERIALS AND METHODS

Sixty patients exhibiting physiological melanin hyperpigmentation in the buccal maxillary gingiva were randomly divided into two equal groups treated with an Er,Cr:YSGG laser at 2780 nm, and a 940 nm diode laser, respectively. The depigmentation procedure essentially involves the ablation of epithelial tissue exhibiting melanin pigmentation. The intensity and extensity indices of gingival pigments were evaluated at baseline, 1 month, 1 year, and 2 years.

RESULTS

At all time points following depigmentation treatment, oral pigmentation index (OPI) and melanin pigmentation index (MPI) scores were less significantly (p <0.05) compared to the baseline in both groups. Treatment was significantly faster with Er,Cr:YSGG laser and required no anesthesia, with faster healing and less postoperative discomfort after 1-week of treatment, compared to the diode laser treatment (p <0.001). The re-pigmentation intensity and extensity were higher significantly in the Er,Cr:YSGG group than in the diode group at 1 year and 2 years (p <0.05).

CONCLUSION

Both lasers efficiently removed gingival pigments with comparable clinical outcomes and overall positive patient experience. Diode laser treatment exhibited better long-term stability of gingival color, with a lower incidence of re-pigmentation.

CLINICAL RELEVANCE

The color of the gingiva plays an important role in the esthetics of oral soft tissues and the overall ideal smile. Laser-assisted gingival depigmentation is an effective, comfortable, and reliable technique with good esthetical outcomes. The rate of re-pigmentation was affected by the laser wavelength and the technique used.

A novel minimally-invasive approach for metal tattoo removal with Er:YAG laser

OBJECTIVE

Few effective and established treatment methods can remove gingival metal or amalgam tattoos. With this case series, we aimed to demonstrate the use of a novel minimally invasive technique to remove metal tattoos using an erbium-doped yttrium aluminum garnet (Er:YAG) laser.

MATERIALS AND METHODS

We retrospectively collected clinical data from 18 patients who had undergone Er:YAG laser treatment to remove metal tattoos. Minimal gingival ablation using an Er:YAG laser directed towards the pigmented area was performed, which exposed metal debris within the connective tissue that was carefully removed. A dental microscope was employed to identify the metal debris, for accurate irradiation, and to minimize wounding by reducing invasion. Postoperative gingival color and morphology, and visual analog scale as a patient-reported outcome assessing postoperative pain were evaluated.

RESULTS

All patients' metal tattoos were removed completely and safely during short procedures. Considerable esthetic improvements and favorable wound healing were achieved with almost no postoperative pain or complications.

CONCLUSION

The findings from this case series suggest that this novel minimally invasive therapy for metal tattoo removal that involved the Er:YAG laser is effective and safe, is associated with successful outcomes, and contributes greatly to patients' esthetic satisfaction.

CLINICAL SIGNIFICANCE

Metal tattoo removal using an Er:YAG laser safely and successfully improved gingival esthetics. This novel technique is much simpler and less invasive than conventional periodontal plastic surgery, and it may be more reliable regarding esthetic gingival improvements as it is associated with favorable wound healing, and it could offer significant benefits to patients by alleviating physical and mental stresses via reduced chair time and postoperative pain.

Efficacy of 980 nm diode laser and 2940 nm Er: YAG laser in gingival depigmentation: A comparative study

BACKGROUND

Gingival hyper-pigmentation is an esthetics problem in patients with excessive gingival display. Laser ablation has been suggested recently as the most effective, pleasant, and reliable technique for gingival depigmentation compared to blade surgery.

AIM

The present study aimed to identify and compare the effectiveness of two types of lasers, Er:YAG laser-2940 nm and Diode laser-980 nm, in gingival depigmentation in the maxilla and mandible.

PATIENTS/METHODS

20 participants, 16 males, and 4 females, whose ages ranged between 18 and 35 years, were recruited using simplified random sampling. Oral pigmentation was measured at pre- and two postoperative follow-ups, 1 month, and 6 months, according to the oral pigmentation index. Furthermore, the study assessed postoperative intensity of pain using the Visual Analogue Scale, bleeding and healing process in both groups.

RESULTS

There was a significant decrease in the oral pigmentation index scores, 1 month (0.90 ± 0.64) and 6 months (1.55 ± 0.60) after the operation (P < .001). No significant differences were detected between the two study groups regarding the mean ranking on the oral pigmentation index pre-operatively (P = .547), 1 month after the operation (P = .154), and 6 months after the operation (P = .831).

CONCLUSIONS

The Er:YAG laser and Diode laser both significantly reduced gingival pigmentation with no significant differences between the effectiveness of the two types of laser in treating gingival hyper-pigmentation.

Laser-Assisted Depigmentation-An Introspection of the Science, Techniques, and Perceptions

BACKGROUND

Gingival hyperpigmentation is a major concern for a significant number of patients, as a relevant aesthetic or cosmetic need. Oral melanin pigmentation is considered to be multifactorial and could be related to physiological or even pathological reasons and can be the consequence of a variety of local or systemic factors. This pigmentation varies individually across races or age groups and is without any gender predilection. Evidence gleaned from literature is presented from case-control studies and from the authors' own research work in prospective, split-mouth, double-blinded, clinical trials comparing treatment modalities in effecting depigmentation.

METHODS

A systematic review of published articles, using suitable assay criteria, was carried out to formulate a consensus on laser-assisted modalities. A total of 295 published sources were subject to critical analysis and resulted in six papers that were subject to data scrutiny. Additionally, evidence is presented on clinical protocols and treatment outcomes.

RESULTS

Analysis of randomized clinical studies identified the use of two laser wavelength groups-near infrared diode and erbium group of mid-infrared lasers. Several areas of analysis were examined, and inconsistent degrees of significance were obtained to establish which laser group was optimal and if they were any better than scalpel depigmentation.

CONCLUSION

A definitive conclusion is wanting as studies with scientific and standardized protocols of evaluation are yet to provide a take on comparative assessments between different techniques of depigmentation.

Laser Treatment for Melanin Gingival Pigmentations: A Comparison Study for 3 Laser Wavelengths 2780, 940, and 445 nm

The normal appearance of the gingiva is pink to light red, and this appearance may change due to many factors and might be noticeable causing aesthetic concerns. In the Gulf area, the gingival melanin pigmentation is of the main type of concern, and patients expect the pigmentation to be removed for aesthetic reasons. Many techniques have been used to remove the melanin pigmentation such as using surgical blades, diamond or ceramic burs, chemicals, and lasers. This study is comparing the results of three lasers (Er, Cr, YSGG 2780 nm, Diode 940 nm, and 445 nm) in the removal of melanin gingival depigmentation. Clinical outcome parameters including bleeding, wound healing, pain, duration of procedure, color improvement, patient satisfaction, and relapse rate after 2 years were assessed. Conclusion. Within the limitation of this study, all three wavelengths were fast, effective in peeling the pigmentations and well tolerated by the patients. The esthetical results were excellent, and the patients were highly satisfied. Suggestion. To have a bigger number of samples in future papers, and histological studies might be included to explore the different impacts of each wavelength on the gingival melanin pigmentation specifically and on the gingival tissue generally.

Photonic Therapy in Periodontal Diseases an Overview with Appraisal of the Literature and Reasoned Treatment Recommendations

Recent reviews and meta-analyses of the literature over the past quarter-century have failed to provide enough evidence to prove or disprove the actual utility of photonic therapy in periodontitis, alone or adjunctive to conventional approaches. This apparent paradox has been explained by the many physical, molecular, biological, anatomical, and technical variables of photonic treatments, which can differ in light-emitting devices (laser or LED), wavelengths, irradiation power and modes, clinical objectives, follow-up times, disease grading, and assessment methods. This multi-faceted, controversial scenario has led practitioners to underestimate the actual potential of photonic therapy in periodontal diseases. In this critical appraisal of the literature, we have briefly summarized the main photonic therapies and instruments used in Periodontology, highlighting their main characteristics and limitations. Then, we have tried to identify and discuss the key methodological issues which can have an impact on the outcome of photonic therapies. Our main goal was to identify the best parameters, settings, and methodologies to perform effective periodontal photonic treatments and to extrapolate some recommendations for clinical use. Should these recommendations find a consensus among periodontologists and be adopted in future clinical studies, they will hopefully contribute to dissipate the present confusion and uncertainty on this complex matter.

Utilizing 808 nm laser for sensitizing of melanoma tumors to megavoltage radiation therapy

Melanotic melanoma has high content of melanin and laser can destroy melanin-containing cells through thermal effect. In this study, the therapeutic effect of 808 nm laser therapy was investigated on B16-F10 melanoma tumor growth and tumor-bearing mice survival time. In addition, as laser can destroy melanin as the main cause of melanoma radioresistance, the effect of laser administration to enhance radiation therapy efficacy at B16-F10 cancer cells was evaluated in vitro and in vivo. Laser therapy (1 W/cm² × 4 min) could cause significant (P < 0.05) inhibition of melanoma tumors' growth (~ 61%) and about three times increase of the tumor-bearing mice survival time in comparison with no-treatment group. In addition, the mice which were treated with 1 W/cm² × 4 min laser administration plus 6 Gy megavoltage radiation therapy exhibited ~ 68% lesser tumors' volume and 27 days increase of survival time in comparison with 6 Gy irradiated tumor-bearing mice. Also, significantly higher (P < 0.05) tumor necrosis percentage was observed at the histopathological slides of 1 W/cm² × 4 min laser + RT treated mice tumors (57 ± 12%) in comparison with radiation therapy group (31 ± 10%). Therefore, not only laser therapy can inhibit melanoma tumors' growth per se but also its combination with radiation therapy can cause a significant enhancement of radiation therapy efficacy. The laser administration can be used as a radiosensitizing method for melanotic melanoma radiation therapy.

Gingival depigmentation by Er,Cr:YSGG laser and diode laser: a split mouth, clinical trial study

Background and aims

The Aim of this study was to evaluate the effectiveness of Diode laser and Er,Cr:YSGG laser ablation on the treatment of physiologic gingival melanin hyperpigmentation.

Materials and methods

This research design was split mouth, double blind, and clinical trial. The power of the diode laser was set at 1 W, fiber 320 µ, irradiation mode: continuous-wave with treatment mode of contact tip and Er,Cr:YSGG laser (2780 nm) was set at 100 MJ, frequency of 15 Hz, total power of 1.75 W, 10% water and 20% air. Bleeding, pain, healing, Dummett oral pigmentation index (DOPI) and Hedin melanin score changes and repigmentation were assessed. Patients were followed for 6 months.

Results

A total number of 14 patients were involved in this study. There were statistically significant differences in reduction of DOPI and Hedin melanin score in each treatment groups separately while diode laser group had better results (P < 0.0001). There was no statistically significant difference between groups in terms of repigmentation. There was more pain in diode laser group (P < 0.0001) and there was more bleeding in Er,Cr:YSGG laser group (P = 0.0156). Gingival healing was more in Er,Cr:YSGG laser group (P < 0.0001).

Conclusion

Diode laser had more efficiency for reduction of DOPI and Hedin melanin index scores.

A comparison of gingival depigmentation by Er:YAG laser and Kirkland knife: osmotic pressure and visual analog scale

Background: The aim of this study was to compare osmotic pressure (OP) 1 week after the gingival depigmentation in two diffeent methods: Er: YAG laser and Kirkland knife. Methods: This study included 20 patients, 13 women, and 7 men who had esthetic complaints of gingival melanin hyperpigmentation. The left side of the maxilla and mandible were depigmented with Er:YAG laser using air and water spray and the right side was removed with a Kirkland knife. Gingival biopsies were obtained from attached gingiva of operation sides with approximate dimensions of 2 mm × 2 mm before and 1 week after the depigmentation. The visual analog scale (VAS) was used to evaluate the pain level experienced by each patient. Results: Patients reported no pain at the gingivoplasty sides after 4 days and at the laser sides after 3 days. There were not statistical differences between laser and gingivoplasty groups according to values of OP (P > 0.05). Conclusion: According to results of wound healing, OP and VAS, two depigmentation procedures can be used safely and effectively.

Comparison of gingival depigmentation with Er,Cr:YSGG laser and surgical stripping, a 12-month follow-up

Gingival melanin hyperpigmentation is an esthetic concern for many individuals. In this study, we compared the standard surgical removal method with two different Er,Cr:YSGG laser settings in order to find the best treatment method. In 33 dental arches, the following three treatment groups were comparatively evaluated: (1) surgical stripping, (2) removal with laser setting 1 (4.5 W, 50 Hz, 100% water, 80% air, 60 μs, 800 μm Tip; MZ8), and (3) laser setting 2 (2.5 W, 50 Hz, 20% water, 40% air, 700 μs, 800 μm Tip; MZ8). We comparatively evaluated pain, patient satisfaction and wound healing, treatment time, and the amount of bleeding. Re-pigmentation was evaluated after 1 and 12 months by Hedin and Dummet pigmentation scores. Laser setting 1 had the best results regarding pain and patient satisfaction, although not statistically significant (P > 0.05). Wound healing results were better using lasers compared to surgical stripping (P < 0.05). Laser setting 1 was a faster procedure with mild amounts of bleeding. The least amount of bleeding was seen with laser setting 2. After 1 month, only two cases of the laser setting 2-treated areas showed an isolated pigmented area in the papilla; at 12 months, the mean Hedin indexes were still less than 2 and mean Dummett index less than 1 in all treatment techniques, with the lowest scores seen in the laser setting 1 sites. Based on our results, Er,Cr:YSGG laser can be more convenient for gingival depigmentation compared to surgical blade. Although not statistically significant, laser setting 1 with shorter pulse duration and higher water spray showed better overall results. However, laser setting 2, with longer pulse duration and less water spray, resulted in better coagulative effects and can be used to control bleeding wherever necessary in clinical practice.

Gingival melanin depigmentation by Er:YAG laser: A literature review

Laser ablation is recently suggested as a most effective and reliable technique for depigmentation of melanin hyperpigmented gingiva. To date, different lasers have been used for gingival depigmentation (CO₂, diode, Nd:YAG, Er:YAG and Er,Cr:YSGG lasers). The use of Er:YAG laser for depigmentation of melanin hyperpigmented gingiva has gained increasing importance in recent years. The purpose of this study was to report removal of gingival melanin pigmentation using an Er:YAG laser in a literature review. The main outcomes, such as improvement of signs (clinical parameters of bleeding, erythema, swelling and wound healing), symptoms (pain) and melanin recurrence/repigmentation were measured. The literature demonstrated that depigmentation of gingival melanin pigmentation can be performed safely and effectively by Er:YAG laser resulting in healing and an esthetically significant improvement of gingival discoloration. Thus, Er:YAG laser seems to be safe and useful in melanin depigmentation procedure. However, the main issue in giving the final conclusion of the optimal Er:YAG laser use in melanin depigmentation is that, to date, studies are offering completely discrepant Er:YAG laser procedure protocols (complex settings of laser parameters), and different criteria for the assessment of depigmentation and repigmentation (recurrence), thus hampering the comparison of the results. Therefore, further studies are necessary to give an optimal recommendation on the use of Er:YAG laser in gingival melanin hyperpigmentation.

Generation and Role of Reactive Oxygen and Nitrogen Species Induced by Plasma, Lasers, Chemical Agents, and Other Systems in Dentistry

The generation of reactive oxygen and nitrogen species (RONS) has been found to occur during inflammatory procedures, during cell ischemia, and in various crucial developmental processes such as cell differentiation and along cell signaling pathways. The most common sources of intracellular RONS are the mitochondrial electron transport system, NADH oxidase, and cytochrome P450. In this review, we analyzed the extracellular and intracellular sources of reactive species, their cell signaling pathways, the mechanisms of action, and their positive and negative effects in the dental field. In dentistry, ROS can be found—in lasers, photosensitizers, bleaching agents, cold plasma, and even resin cements, all of which contribute to the generation and prevalence of ROS. Nonthermal plasma has been used as a source of ROS for biomedical applications and has the potential for use with dental stem cells as well. There are different types of dental stem cells, but their therapeutic use remains largely untapped, with the focus currently on only periodontal ligament stem cells. More research is necessary in this area, including studies about ROS mechanisms with dental cells, along with the utilization of reactive species in redox medicine. Such studies will help to provide successful treatment modalities for various diseases.

Treatment of oral hyperpigmentation and gummy smile using lasers and role of plasma as a novel treatment technique in dentistry: An introductory review

Gingival hyperpigmentation and the condition known as gummy smile are very common dental cosmetic problems. Gingival hyperpigmentation arises due to the excess presence of melanin in certain regions of the gums. In the case of gummy smile, more than the required amount of gingival tissue is exposed upon smiling. An aesthetically pleasing smile should expose only a negligible amount of gingival tissue. Gummy smile and gingival hyperpigmentation can have detrimental effects on the aesthetic quality of a smile, and thereby a wide variety of treatment options must be taken into consideration depending patient outcome objectives. The use of a laser as a treatment modality is considered to be a promising option for such cases. We aim to explain the effects of using a laser on the gingiva and discuss the advantages and disadvantages of this type of treatment and the resulting alteration of the genetic composition of the gingival tissue. This article reviews the histological aspects and biological effects of a laser treatment for oral hyperpigmentation and gummy smile and analyzes the use of the laser as a modality to improve the smiles of people with hyperpigmentation and excessive gingival display. We also attempt to provide insight into the use of plasma as a novel technology for medical and dental research and its future implications with regard to, dental soft tissue procedures.

Periodontal and peri-implant wound healing following laser therapy

Laser irradiation has numerous favorable characteristics, such as ablation or vaporization, hemostasis, biostimulation (photobiomodulation) and microbial inhibition and destruction, which induce various beneficial therapeutic effects and biological responses. Therefore, the use of lasers is considered effective and suitable for treating a variety of inflammatory and infectious oral conditions. The CO2 , neodymium-doped yttrium-aluminium-garnet (Nd:YAG) and diode lasers have mainly been used for periodontal soft-tissue management. With development of the erbium-doped yttrium-aluminium-garnet (Er:YAG) and erbium, chromium-doped yttrium-scandium-gallium-garnet (Er,Cr:YSGG) lasers, which can be applied not only on soft tissues but also on dental hard tissues, the application of lasers dramatically expanded from periodontal soft-tissue management to hard-tissue treatment. Currently, various periodontal tissues (such as gingiva, tooth roots and bone tissue), as well as titanium implant surfaces, can be treated with lasers, and a variety of dental laser systems are being employed for the management of periodontal and peri-implant diseases. In periodontics, mechanical therapy has conventionally been the mainstream of treatment; however, complete bacterial eradication and/or optimal wound healing may not be necessarily achieved with conventional mechanical therapy alone. Consequently, in addition to chemotherapy consisting of antibiotics and anti-inflammatory agents, phototherapy using lasers and light-emitting diodes has been gradually integrated with mechanical therapy to enhance subsequent wound healing by achieving thorough debridement, decontamination and tissue stimulation. With increasing evidence of benefits, therapies with low- and high-level lasers play an important role in wound healing/tissue regeneration in the treatment of periodontal and peri-implant diseases. This article discusses the outcomes of laser therapy in soft-tissue management, periodontal nonsurgical and surgical treatment, osseous surgery and peri-implant treatment, focusing on postoperative wound healing of periodontal and peri-implant tissues, based on scientific evidence from currently available basic and clinical studies, as well as on case reports.

Colorimetric distribution of human attached gingiva and alveolar mucosa

STATEMENT OF PROBLEM

Few studies have investigated the colorimetric distribution of gingival color, including the posterior area and alveolar mucosa.

PURPOSE

The purpose of this in vivo study was to investigate the distribution of colorimetric values in different areas of gingiva and to determine its relationship to colorimetric findings of the tooth and skin in a young Korean population.

MATERIAL AND METHODS

Participants included 40 periodontally healthy adults (22 men and 18 women) 25 to 36 years of age. Commission Internationale de l'Eclairage values (CIELab: L* lightness, a* green-red, and b* blue-yellow) were measured using a colorimeter at a total of 23 sites for each participant, including attached gingiva (AG) and alveolar mucosa (AM) in the maxillary and mandibular and incisor and molar regions, maxillary central incisor, and skin points of the glabella, cheek, and inner upper arm.

RESULTS

AG showed higher L* and lower a* values than AM. AG demonstrated higher L* and lower a* values in the maxillary region than in the mandibular region and higher b* values in the incisor region than in the molar region. AM revealed higher L* and lower a* and b* values in the incisor region than in the molar region. Positive significant correlations were found for L* between the skin area and AM and for b* between the skin area and AG.

CONCLUSIONS

The colorimetric values of AG and AM differ according to the area, possibly as a result of differences in anatomic and histologic distribution that influence optical properties.

Energy output reduction and surface alteration of quartz tips following Er:YAG laser contact irradiation on soft and hard tissues in vitro

Though the Er:YAG laser (ErL) has been used in periodontal therapy, the irradiated tip damage has not been studied in detail. In this study, the change in the energy output, surface morphology, and temperature of quartz tips was evaluated following contact irradiation. Soft tissue, calculus on extracted human teeth, and porcine bone were irradiated by ErL for 60 min at 14.2 or 28.3 J/cm(2)/pulse and 20 Hz with or without water spray. The energy output ratio declined the most in the calculus group, followed by the bone and soft tissue groups with and/or without water spray. Carbon contamination was detected in all groups, and contamination by P, Ca, and/or other inorganic elements was observed in the calculus and bone groups. The rate of energy output reduction and the degree of surface alteration/contamination is variously influenced by the targeting tissue, temperature elevation of the tip and water spray.

Er:YAG Laser Versus Cold Knife Excision in the Treatment of Nondysplastic Oral Lesions: A Randomized Comparative Study for the Postoperative Period

OBJECTIVE

The aim of this prospective study was to estimate the effects of Erbium substituted: Yttrium Aluminium Garnet (Er:YAG) laser, compared with traditional scalpel, on the early postoperative sequelae of nondysplastic oral lesion removal.

BACKGROUND DATA

There is limited evidence that laser surgery could exhibit advantages over scalpel in oral mucosal surgery.

METHODS

The investigators studied a cohort of 344 patients; 394 lesions were randomized and treated. Outcome statistically evaluated variables were: age, gender, the site and size of investigated lesions, visual analogue score (VAS) of pain, the Oral Health Impact Profile questionnaire (OHIP-14) and the Quality of Life test (QOL), and number of analgesics taken in the 1st week after surgery.

RESULTS

Significant differences were found if considering the surgical time, VAS, and QOL and OHIP-14 questionnaires; regarding those data, the Er:YAG laser appeared to be faster and less painful than traditional scalpel (p < 0.05). For bigger lesions, patients statistically took more painkillers if they had undergone traditional surgery. Considering the site of the treated lesions, Er:YAG laser was less painful, especially in the gingiva and palate (p < 0.05).

CONCLUSIONS

This is the first randomized controlled surgical trial reported for the management of nondysplastic oral lesions with the use of an Er:YAG laser. With many limitations, the present report identifies significant difference in the immediate postoperative surgical period between the two treatments, meaning that the Er:YAG laser seemed to be less painful, and better accepted by patients, than traditional scalpel.

Lasers in esthetic treatment of gingival melanin hyperpigmentation: a review article

The health and suitability of mouth components play an important role towards defining facial attractiveness. An important component of the oral cavity is the color of the gingival tissue. Gingival melanin hyperpigmentation is caused by several reasons and affects people across ethnicity, race, age, and both gender. Lasers are presently being used for gingival melanin depigmentation. In this article, we reviewed studies on laser parameters, duration of gingival healing, pain perception during and after the operation, scores used for the evaluation of gingival melanin hyperpigmentation, follow-up period, treatment results, and recurrence reports. We conclude that laser ablation for gingival depigmentation is one of the most pleasant, reliable, acceptable, and impressive techniques available for treating gingival melanin hyperpigmentation.

Treatment of Gingival Hyperpigmentation by Diode Laser for Esthetical Purposes

BACKGROUND:

Gingival hyperpigmentation is a common esthetical concern in patients with gummy smile or excessive gingival display. Laser ablation has been recognized recently as the most effective, pleasant and reliable technique. It has the advantage of easy handling, short treatment time, hemostasis, decontamination, and sterilization effect.

AIM:

In the present study we wanted to explore the efficacy of a 980 nm wavelength diode laser in gingival depigmentation clinically by using both VAS and digital imaging method as means of assessment.

METHODS:

Diode laser ablation was done for 15 patients who requested cosmetic therapy for melanin pigmented gums. The laser beam delivered by fiberoptic with a diameter of 320 µm, the diode laser system has 980 nm wave lengths and 3 W irradiation powers, in a continuous contact mode in all cases, the entire surface of each pigmented maxillary and mandibular gingiva that required treatment was irradiated in a single session. Clinical examination and digital image analysis were done and the patients were followed up for 3 successive months.

RESULTS:

There was a statistically significant change in prevalence of bleeding after treatment, as none of the cases showed any signs of bleeding 1 week, 1 month and 3 months after ablation. No statistically significant change was observed in the prevalence of swelling after treatment The VAS evaluation demonstrated that only 4 patients complained of mild pain immediately after the procedure. No pain was perceived from the patients in the rest of the follow up period. There was no statistically significant change in prevalence of pain immediately after treatment compared to pain during treatment. There was a decrease in cases with mild pain after 1 week, 1 month as well as 3 months compared to pain during treatment and immediately after treatment.

CONCLUSION:

Within the limitations of this study, the use of diode laser was shown to be a safe and effective treatment modality that provides optimal aesthetics with minimal discomfort in patients with gingival hyperpigmentation.

Systematic review of treatment modalities for gingival depigmentation: a random-effects poisson regression analysis

OBJECTIVE

Repigmentation variably occurs with different treatment methods in patients with gingival pigmentation. A systemic review was conducted of various treatment modalities for eliminating melanin pigmentation of the gingiva, comprising bur abrasion, scalpel surgery, cryosurgery, electrosurgery, gingival grafts, and laser techniques, to compare the recurrence rates (Rrs) of these treatment procedures.

MATERIAL AND METHODS

Electronic databases, including PubMed, Web of Science, Google, and Medline were comprehensively searched, and manual searches were conducted for studies published from January 1951 to June 2013. After applying inclusion and exclusion criteria, the final list of articles was reviewed in depth to achieve the objectives of this review. A Poisson regression was used to analyze the outcome of depigmentation using the various treatment methods.

RESULTS

The systematic review was based on case reports mainly. In total, 61 eligible publications met the defined criteria. The various therapeutic procedures showed variable clinical results with a wide range of Rrs. A random-effects Poisson regression showed that cryosurgery (Rr = 0.32%), electrosurgery (Rr = 0.74%), and laser depigmentation (Rr = 1.16%) yielded superior result, whereas bur abrasion yielded the highest Rr (8.89%).

CONCLUSIONS

Within the limit of the sampling level, the present evidence-based results show that cryosurgery exhibits the optimal predictability for depigmentation of the gingiva among all procedures examined, followed by electrosurgery and laser techniques.

CLINICAL SIGNIFICANCE

It is possible to treat melanin pigmentation of the gingiva with various methods and prevent repigmentation. Among those treatment modalities, cryosurgery, electrosurgery, and laser surgery appear to be the best choices for treating gingival pigmentation.

Gingival tissue healing following Er:YAG laser ablation compared to electrosurgery in rats

The erbium-doped yttrium aluminum garnet (Er:YAG) laser is currently used for periodontal soft tissue management with favorable outcomes. However, the process of wound healing after Er:YAG laser (ErL) treatment has not been fully elucidated yet. The aim of this study was to investigate the gingival tissue healing after ErL ablation in comparison with that after electrosurgery (ElS). Gingival defects were created in 28 rats by ablation with ErL irradiation or ElS. The chronological changes in wound healing were evaluated using histological, histometrical, and immunohistochemical analyses. The ErL-ablated gingival tissue revealed much less thermal damage, compared to the ElS. In the ElS sites, the postoperative tissue destruction continued due to thermal damage, while in the ErL sites, tissue degradation was limited and the defects were re-epithelialized early. Heat shock protein (Hsp) 72/73 expression was detected abundantly remote from the wound in the ElS, whereas it was slightly observed in close proximity to the wound in the ErL sites. Hsp47 expression was observed in the entire connective tissue early in the wound healing and was found limited in the wound area later. This phenomenon proceeded faster in the ErL sites than in the ElS sites. Expression of proliferating cell nuclear antigen (PCNA) persisted in the epithelial tissue for a longer period in the ElS than that in the ErL. The ErL results in faster and more favorable gingival wound healing compared to the ElS, suggesting that the ErL is a safe and suitable tool for periodontal soft tissue management.

Esthetic treatment of gingival hyperpigmentation with Nd:YAG laser or scalpel technique: a 6-month RCT of patient and professional assessment

This double-masked, randomized controlled trial with a split-mouth design aimed to compare patient- and professional-centered outcomes using different therapeutic approaches-neodymium-yttrium aluminum garnet (Nd:YAG) laser or scalpel technique-for gingival depigmentation. Patients presenting bilateral melanin gingival hyperpigmentation and who requested cosmetic therapy were recruited. Contralateral quadrants were randomly assigned to receive Nd:YAG laser (settings: 6 W, 60 mJ/pulse, and 100 Hz) or scalpel technique. Patient morbidity experienced at intratherapy and during the first postoperative week was evaluated. In addition, after 6 months, the cosmetic results achieved for the different therapeutic approaches were evaluated by patients and professionals. The chair time of each technique was also calculated. Patient-oriented outcomes concerning intratherapy morbidity did not demonstrate any differences between groups (p > 0.05), although a higher extent of discomfort/pain was experienced in the side treated by the scalpel technique compared to the Nd:YAG laser procedure during the first posttherapy week (p < 0.05). Regarding to cosmetic outcomes, no differences between techniques were observed for patient and professionals (p > 0.05). Significantly higher chair time was required for the scalpel technique than for the Nd:YAG laser therapy (p < 0.05). The Nd:YAG laser or the scalpel technique may be successfully used for the treatment of melanin gingival hyperpigmentation. However, the use of the Nd:YAG laser has presented advantages in terms of less discomfort/pain during the posttherapy period and a reduction of treatment chair time.

A comparison of different gingival depigmentation techniques: ablation by erbium:yttrium-aluminum-garnet laser and abrasion by rotary instruments

PURPOSE

The aim of this study is to compare two different gingival depigmentation techniques using an erbium:yttrium-aluminum-garnet (Er:YAG) laser and rotary instruments.

METHODS

Two patients with melanin pigmentation of gingiva were treated with different gingival depigmentation techniques. Ablation of the gingiva by Er:YAG laser was performed on the right side, and abrasion with a rotary round bur on the opposite side.

RESULTS

The patients were satisfied with the esthetically significant improvement with each method. However, some pigment still remained on the marginal gingival and papilla. The visual analog scale did not yield much difference between the two methods, with slightly more pain on the Er:YAG laser treated site.

CONCLUSIONS

The results of these cases suggest that ablation of the gingiva by an Er:YAG laser and abrasion with a rotary round bur is good enough to achieve esthetic satisfaction and fair wound healing without infection or severe pain. Prudent care about the gingival condition, such as the gingival thickness and degree of pigmentation along with appropriate assessment is needed in ablation by the Er:YAG laser procedure.

Esthetic treatment of gingival melanin hyperpigmentation with a Nd:YAG laser and high speed rotary instrument: comparative case report

Purpose

The purpose of this study was to evaluate the clinical effectiveness of and patient's satisfaction with treatment of gingival melanin hyperpigmentation with a Nd:YAG laser and a high speed rotary instrument.

Methods

Three patients with melanin hyperpigmentation in the anterior parts of the gingiva were chosen for this case study. Clinical photographs were taken at the preoperative state and three patients were treated under local anesthesia. In the maxilla, the gingival deepithelization was conducted with a high speed diamond bur, whereas, in the mandible with a Nd:YAG laser. Clinical photographs were taken immediately after the procedures and at the 1st, 2nd, and 4th week to evaluate clinical color changes. A week after the procedure, the patients filled out a questionnaire about any pain or discomfort. At the 4th week after the procedure, the patients filled out questionnaires about esthetic aspects of the results of treatment.

Results

In all cases, both anterior gingival areas were depigmented with satisfaction and the patients did not complain of severe pain or discomfort. At the 1st week of healing, the gingiva showed moderate to fast epithelization. Two weeks after the procedure, clinically, the gingiva showed almost complete healing. Four weeks after the procedure, there was significant improvement in gingival melanin hyperpigmentation.

Conclusions

The Nd:YAG laser and the high speed rotary instruments seem to be effective for the esthetic treatment of gingival melanin hyperpigmentation.

In vitro studies of the ablation mechanism of periodontopathic bacteria and decontamination effect on periodontally diseased root surfaces by erbium:yttrium-aluminum-garnet laser

The erbium:yttrium-aluminum-garnet (Er:YAG) laser is now increasingly used in periodontal therapy. The purpose of this study was to investigate the effect of Er:YAG laser irradiation on the morphology of periodontopathic bacteria and to compare the bacterial elimination effect of the laser and the ultrasonic scaler on diseased root surfaces in vitro. Colonies of Porphyromonas gingivalis were exposed to a single-pulse Er:YAG laser at 40 mJ and were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Also, 20 pairs of periodontally diseased root surfaces with subgingival calculi of freshly extracted teeth were treated by Er:YAG laser scaling at 40 mJ/pulse (14.2 J/cm(2) per pulse) and 10 Hz with water spray or ultrasonic scaling, or were not treated. The efficiency of each treatment was determined as the area treated per second, and the treated surfaces were examined by SEM. The material scraped from the treated root surfaces was cultured in aerobic and anaerobic conditions, and the numbers of colony forming units (CFUs) were compared. SEM and TEM showed that the Er:YAG laser had easily ablated the bacterial colony, leaving an ablation spot with a crater and the surrounding affected area showing melted branch-like structures. The laser irradiation was as equally effective and efficient as the ultrasonic scaler in performing root surface debridement. The CFUs after laser treatment were significantly fewer than those after ultrasonic scaling in aerobic and anaerobic culture conditions. Er:YAG laser ablates periodontopathic bacteria with thermal vaporization, and its bacterial elimination effect on the diseased root surfaces appears to be superior to that of the ultrasonic scaler.

Effects of KTP laser on oral soft tissues. An in vitro study

A biopsy is a surgical procedure performed to establish a clear diagnosis of a lesion in order to clarify a clinical diagnostic suspicion. During a biopsy procedure it is fundamental to maintain safe and readable cut margins in order to permit histological visualization of possible marginal infiltrations or malignant transformation of a lesion. The aim of this study was to evaluate the histological peripheral damage caused by application of a KTP (potassium titanium phosphate) laser during oral soft tissue biopsy procedures. A KTP laser (lambda 532 nm) at different power settings and fluences was used to obtain 45 samples from pig cadaver tongues. The samples were then subdivided into five groups of nine samples each. A final specimen was taken by scalpel as a control. All samples were put into test tubes containing 10% buffered formalin solution, and were examined separately under an optical microscope by two pathologists to evaluate the peripheral thermal damage induced by the laser. In all specimens the cut edges of the incision were free from histological artefacts, especially when lower settings were applied. Statistical analysis showed no differences among the groups. The KTP laser demonstrated surgical effectiveness and caused little peripheral damage to the cut edges, and therefore would always allow a safe histological diagnosis to be obtained.

Bone damage induced by different cutting instruments--an in vitro study

The aim of this study was to compare the peripheral bone damage induced by different cutting systems. Four devices were tested: Er:YAG laser (2.94 mm), Piezosurgery, high-speed drill and low-speed drill. Forty-five bone sections, divided into 9 groups according to different parameters, were taken from pig mandibles within 1 h post mortem. Specimens were fixed in 10% buffered formalin, decalcified and cut in thin sections. Four different parameters were analyzed: cut precision, depth of incision, peripheral carbonization and presence of bone fragments. For statistical analysis, the Kruskal-Wallis test was applied to assess equality of sample medians among groups. All sections obtained with the Er:YAG laser showed poor peripheral carbonization. The edges of the incisions were always well-shaped and regular, no melting was observed. Piezosurgery specimens revealed superficial incisions without thermal damage but with irregular edges. The sections obtained by traditional drilling showed poor peripheral carbonization, especially if obtained at lower speed. There was statistically significant differences (p<0.01) among the cutting systems for all analyzed parameters. Er:YAG laser, gave poor peripheral carbonization, and may be considered an effective method in oral bone biopsies and permits to obtain clear and readable tissue specimens.

Long-term histologic analysis of bone tissue alteration and healing following Er:YAG laser irradiation compared to electrosurgery

BACKGROUND

The erbium-doped:yttrium, aluminum, and garnet (Er:YAG) laser is reportedly useful for periodontal therapy. However, the potential thermal damage that Er:YAG laser irradiation can produce on bone tissue has not been fully clarified. The purpose of this study was to histologically examine the effects of the Er:YAG laser on bone tissue and subsequent wound healing compared to electrosurgery in a long-term study.

METHODS

Calvarial bone from 30 rats was exposed to contact and non-contact Er:YAG laser irradiation (115 mJ/pulse, 10 Hz) without water coolant, or electrode contact. The treated surfaces were analyzed by scanning electron microscopy (SEM), and the healing process was histologically observed until 12 months post-surgery.

RESULTS

Contact irradiation resulted in substantial bone ablation, whereas non-contact irradiation produced slight tissue removal. Histologic and SEM analyses of the lased surface showed no severe thermal damage, except for the production of a superficially affected layer with a microstructured surface. The layer did not inhibit new bone formation, and the ablated defect was repaired uneventfully. Although the thickness of the layer gradually decreased, it generally remained in the cortical bone through the observation period. Electrosurgery produced a large area of thermal necrosis without ablation, and the damaged area was not replaced with new bone.

CONCLUSIONS

Unlike electrosurgery, Er:YAG laser irradiation without water coolant easily ablated bone tissue, and thermal alteration in the treated surface was minimal. The superficially affected layer did not interfere with the ensuing bone healing, resulting in favorable repair of the defect.