Journal of Lasers in Medical Sciences

The minimal invasive nature of lasers, with quick tissue response and healing has made them a very attractive technology in various fields of dentistry which serves as a tool to create a better result than ever before. The rapid development of lasers and their wavelengths with variety of applications on soft and hard tissues may continue to have major impact on the scope and practice in prosthetic dentistry. The purpose of this article is to make every clinician familiar with the fundamentals of lasers and different laser systems to incorporate into their clinical practices.

Introduction: When aesthetics is compromised, dental ceramics are excellent materials for dental restorations; owing to their optical properties and biocompatibility, zirconia ceramics are particularly interesting. Self-adhesive resin cements are the most suitable for bonding to zirconia ceramics, but traditional adhesive chemistry is ineffective and surface treatments are required to improve the adhesive bonding between resin and zirconia. The aim of this study was to evaluate the effect of femtosecond laser treatment on the shear bond strength (SBS) of self-adhesive resin cement on zirconia surfaces and to contrast it with other different surface conditioning methods.

Methods: Sixty square-shaped zirconia samples were divided randomly into four groups (n = 15) according to their surface conditioning method: the NT group - no surface treatment; the APA25 group - airborne abrasion with 25 μm alumina particles; the TSC group - tribochemical silica coating, and the FS group - femtosecond laser irradiation (800 nm, 4 mJ, 40 fs/pulse, 1 kHz). Self-adhesive resin cements were bonded at the centre of samples, and after 72 hours, they were tested for SBS with a universal testing machine at a crosshead speed of 0.5 mm/min, until fracture. Five zirconia surfaces for each group were subjected to a surface morphology analysis by scanning electron microscopy (SEM). The failure modes were noted and a third of the specimens were prepared to morphological analysis.

Results: The NT group showed lower SBS values than the other groups. Femtosecond laser treatment demonstrated higher values than the control and APA25 groups and similar values to those of the TSC group. In the APA25 group, the surface conditioning method had values close to those of the TSC group, but lower than those obtained with femtosecond laser treatment.

Conclusion: The treatment of zirconia with femtosecond laser irradiation created a consistent and profound surface roughness, improving the adhesive effectiveness of the zirconia-resin interface.

Introduction: Deep periodontal pockets pose a great challenge for nonsurgical periodontal treatment. Scaling and root planing (SRP) alone may not suffice in cases where surgical therapy cannot be undertaken. Various recent studies have suggested the use of antimicrobial Photodynamic Therapy (aPDT) for the management of periodontal infections. The aim of this study was to evaluate the effects of using aPDT along with SRP, compared to SRP alone for the management of deep periodontal pockets.

Methods: Thirty patients with chronic periodontitis, who met the criteria of having periodontal pockets with depth ≥ 6 mm and bleeding on probing (BOP) in at least 2 different quadrants were included. After SRP, one quadrant was randomly selected for aPDT (test), while another served as control. Clinical parameters i.e. plaque index (PI), modified sulcular bleeding index (mSBI), probing depth (PD) and clinical attachment level (CAL) were measured at baseline, 1 month and 3 months post-treatment intervals.

Results: All clinical parameters significantly improved in both groups after 1 and 3 months. At 1-month interval, inter-group difference in mean change was statistically significant (P < 0.05) in terms of mSBI (0.85 ± 0.41in test vs 0.54 ± 0.47 in control group) and PD (1.77±0.86 in test vs 1.3 ± 0.95 in control group). At 3 months interval, no statistically significant difference was observed between test and control groups except in terms of mSBI (0.97 ± 0.45 in test vs 0.73 ± 0.42 in control group).

Conclusion: aPDT appears to play an additional role in reduction of gingival inflammation when used along with nonsurgical mechanical debridement of deep periodontal pockets.

Introduction: Dark or black coloured gingiva is an esthetic concern especially in subjects with high lip line or gummy smile. Gingival depigmentation procedure is a type of perioplastic surgery where the gingival epithelium is excised with various techniques to lighten the colour of the gingiva. The aim of this study was to compare the clinical efficacy of gingival depigmentation procedure with conventional scalpel technique and diode laser application.

Methods: This split mouth randomized study was conducted on 12 subjects (18–40 years of age), exhibiting melanin hyperpigmentation of gingiva. The anterior labial sextant of maxilla and mandible were divided into two halves involving three anterior teeth i.e. central incisor, lateral incisor and canine on each side. The divided areas were randomly allotted for depigmentation procedure either with scalpel technique or diode laser operating at 980 nm wavelength. Various parameters such as bleeding, pain, difficulty of procedure and wound healing were assessed and compared between the two techniques. The level of melanin pigment was assessed with Dummette Gupta index and photographic analysis with the help of adobe software. The subjects were followed up to one year to see for recurrence of melanin pigmentation.

Results: Bleeding during surgery, pain score and difficulty of procedure assessed by the operator were statistically higher for scalpel technique as compared to laser technique. Wound healing did not show any statistical significant difference between both techniques. Gingival depigmentation procedures with scalpel as well as laser technique were effective when compared preoperatively and at consecutive postoperative visits, and this was statistically significant. Comparison of melanin depigmentation procedure between scalpel and laser technique did not show any significant differences at all postoperative intervals.

Conclusion: The findings of the present study suggest that gingival depigmentation was effective with both scalpel and laser techniques. However, the laser treated sites showed reduced pain experienced by the patient and better operator comfort. Slight melanin repigmentation was observed in three subjects treated with scalpel depigmentation procedure at the end of one year.

Introduction: Single fiber reflectance spectroscopy (SFRS) is a noninvasive procedure to quantitate tissue absorption and scattering properties. It can be used to diagnose different diseases such as malignancy and pre-cancerous conditions. The measurement is done with a fiber optic probe in contact with the tissue surface. Herein, the effect of probe pressure on the extracted parameters from human lip spectra was studied.

Methods: Thirty-three normal subjects were examined with three exerted pressure levels on the right, middle and left parts of their lips.

Results: The results showed variation of spectroscopic parameters with different pressure levels. However, the effect was seen between a very mild contact (pressure 1) and the other reasonably practical pressure levels normally used in the medical centers.

Conclusion: SFRS can be used as a reliable diagnostic tool in clinics.

Introduction: Root canal therapy as a routine dental procedure has resulted in retention of millions of teeth that would otherwise be lost. Unfortunately, successful outcomes are not always achievable within initial endodontic treatments, and that necessitates further treatment. Nonsurgical retreatment is the first choice in most clinical situations. The aim of this clinical pilot study was to assess the effect of additional photodynamic therapy (PDT) on intraradicular bacterial load following retreatment of failed previously root treated teeth.

Methods: Thirty single-rooted/canalled endodontically treated matured teeth (in 27 healthy patients) accompanied by apical periodontitis (AP) were selected for this study. Standard protocol was followed for nonsurgical retreatment of each tooth. Microbiological samples were taken after establishment of apical patency, finished cleaning/shaping procedure, and PDT (665 nm, 1 W, 240 seconds). All samples were cultured for 72 hours and colony-forming unit (CFU) was counted. McNemar test was used for statistical analysis of the data. The level of significance was set at 0.001.

Results: Routine cleaning and shaping resulted in twenty four negative (80%) out of 30 cultures. Four additional negative results were obtained after additional PDT (93.3%). The addition of PDT to routine procedures significantly enhanced the number of bacteria-free samples (P < 0.001).

Conclusion: Regarding elimination of intraradicular microbiota, additional PDT may increase the effectiveness of conventional chemomechanical preparation in previously root filled teeth accompanied by AP. Well controlled randomized clinical trials should be planned for future.

Introduction: The periodontal therapy is primarily targeted at removal of dental plaque and plaque retentive factors. Although the thorough removal of adherent plaque, calculus and infected root cementum is desirable, it is not always achieved by conventional modalities. To accomplish more efficient results several alternative devices have been used. Lasers are one of the most promising modalities for nonsurgical periodontal treatment as they can achieve excellent tissue ablation with strong bactericidal and detoxification effects.

Methods: Thirty freshly extracted premolars were selected and decoronated. The mesial surface of each root was divided vertically into four approximately equal parts. These were distributed into four group based on the root surface treatment. Part A (n = 30) was taken as control and no instrumentation was performed. Part B (n = 30) was irradiated by Erbium, Chromium doped Yttrium Scandium Gallium Garnet (Er,Cr:YSGG) laser. Part C (n = 30) was treated by piezoelectric ultrasonic scaler. Part D (n = 30) was treated by Gracey curette. The surface roughness was quantitatively analyzed by profilometer using roughness average (Ra) value, while presence of smear layer, cracks, craters and melting of surface were analyzed using scanning electron microscope (SEM). The means across the groups were statistically compared with control using Dunnett test.

Results: Among the test groups, Er,Cr:YSGG laser group showed maximum surface roughness (mean Ra value of 4.14 μm) as compared to ultrasonic scaler (1.727 μm) and curette group (1.22 μm). However, surface with smear layer were found to be maximum (50%) in curette treated samples and minimum (20%) in laser treated ones. Maximum cracks (83.34%) were produced by ultrasonic scaler, and minimum (43.33%) by curettes. Crater formation was maximum (50%) in laser treated samples and minimum (3.33%) in curette treated ones. 63.33% samples treated by laser demonstrated melting of root surface, followed by ultrasonic scaler and curettes.

Conclusion: Er,Cr:YSGG laser produced maximum microstructural changes on root surface that can influence the attachment of soft periodontal tissues as well as plaque and calculus deposition. In vivo studies are needed to validate these results and to evaluate their clinical effects.

Introduction: The aim of this study was to evaluate the efficacy of combination therapy of diode laser and photodynamic therapy (PDT) as an adjunct to scaling and root planing (SRP) on interleukin-17 (IL-17) levels in gingival crevicular fluid (GCF) in patients with chronic periodontitis.

Methods: Thirty subjects with chronic periodontitis were included. All teeth received periodontal treatment comprising of SRP. Using a split mouth study design, the test group was additionally treated with a combination therapy of diode laser and PDT. GCF was collected to evaluate IL-17 levels at baseline and 3 months.

Results: There was no difference in baseline values for levels of IL-17 in GCF in the test group and the control group. A significant decrease in GCF levels of IL-17 was observed in both treatment groups 3 months after treatment (P < 0.001). However, the treatment groups showed no significant difference (P > 0.05).

Conclusion: Based on the results of the present study it was concluded that, GCF levels of IL-17 changed significantly after treatment regardless of treatment modality.

Introduction: Despite its clinical features of multiple, confluent, small, whitish, smooth, and clear-demarcate papules on the neck and back, the pathogenesis of white fibrous papulosis of the neck (WFPN) is still unknown. The lesions increase progressively and do not regress over time. However, no effective treatment has yet been identified.

Case Report: We reported the successful results of a female patient receiving efficacious treatment for her extensive lesions of WFPN with nonablative fractional photothermolysis laser (Fractionated 1550-Erbium Glass laser).

Conclusion: This photothermolysis laser could then be suggestive as the therapeutic option for WFPN.

Introduction: Periosteal releasing incision (PRI) is nearly always essential to advance the flap sufficiently for a tension-free flap closure in bone augmentation procedures. However, hematoma, swelling, and pain are recognized as the main consequences of PRI with scalpel. The aim of this case series was to investigate the effectiveness of laser-assisted PRI in guided bone regeneration (GBR) procedure. In addition, postoperative hematoma, swelling, and pain and implant success were assessed.

Methods: Seventeen patients needed GBR were included in this study. Diode laser (940 nm, 2 W, pulse interval: 1 ms, pulse length: 1 ms, contact mode, 400-μm fiber tip) was used in a contact mode to cut the periosteum to create a tension-free flap. Facial hematoma, swelling, pain, and the number of consumed nonsteroidal anti-inflammatory drugs (NSAIDs) were measured for the six postoperative days. Six months after implant loading, implant success was evaluated.

Results: Minimal bleeding was encountered during the procedure. A tension-free primary closure of the flap was achieved in all cases. The clinical healing of the surgical area was uneventful. None of the patients experienced hematoma, ecchymosis, or intense swelling after surgery. The mean value of maximum pain (visual analogue scale – VAS) was 20.59 ± 12.10 mm (mild pain). Patients did not need to use NSAID after four postoperative days. All implants were successful and functional and none of them failed after 6 months of implant loading.

Conclusion: This study revealed the effectiveness of laser-assisted PRI in GBR procedure. This technique was accompanied with minimal sequelae at the first postoperative week. All implants were successful and no complication was noted during the course of this study.