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

Insights into Intra Periodontal Pocket Pathogenesis, Treatment, In Vitro-In Vivo Models, Products and Patents, Challenges and Opportunity

Periodontal disease is a multifactorial pathogenic condition involving microbial infection, inflammation, and various systemic complications. Here, a systematic and comprehensive review discussing key-points such as the pros and cons of conventional methods, new advancements, challenges, patents and products, and future prospects is presented. A systematic review process was adopted here by using the following keywords: periodontal diseases, pathogenesis, models, patents, challenges, recent developments, and 3-D printing scaffolds. Search engines used were "google scholar", "web of science", "scopus", and "pubmed", along with textbooks published over the last few decades. A thorough study of the published data rendered an accurate and deep understanding of periodontal diseases, the gap of research so far, and future opportunities. Formulation scientists and doctors need to be interconnected for a better understanding of the disease to prescribe a quality product. Moreover, prime challenges (such as a lack of a vital testing model, scarcity of clinical and preclinical data, products allowing for high drug access to deeper tissue regions for prolonged residence, lack of an international monitoring body, lack of 4D or time controlled scaffolds, and lack of successful AI based tools) exist that must be addressed for designing new quality products. Generally, several products have been commercialized to treat periodontal diseases with certain limitations. Various strategic approaches have been attempted to target certain delivery regions, maximize residence time, improve efficacy, and reduce toxicity. Conclusively, the current review summarizes valuable information for researchers and healthcare professional to treat a wide range of periodontal diseases.

Effect of erbium, chromium-doped: yttrium, scandium, gallium, and garnet laser-assisted periodontal therapy using radial firing tip during early healing period: a randomized controlled split-mouth clinical trial

BACKGROUND

This study aimed to demonstrate the efficacy of erbium, chromium-doped:yttrium, scandium, gallium, and garnet (Er,Cr:YSGG) laser-assisted nonsurgical periodontal therapy in periodontitis patients during 8 weeks of healing.

METHODS

A split-mouth, single-blinded, randomized controlled clinical trial was conducted on 12 patients diagnosed with stage III/IV periodontitis and had a minimum of two teeth with probing pocket depth (PPD) > 5 mm in at least two quadrants. Upon randomization, each quadrant was assigned for conventional scaling and root planing (SRP) procedure or laser-assisted therapy (SRP + laser) using radial firing tip (RFPT 5, Biolase). Clinical measurements and gingival crevicular fluid collection were performed for statistical analysis.

RESULTS

In the initial statistical analysis on the whole subject teeth, modified gingival index (MGI) reduction was greater in test group at 1(P = 0.0153), 4 (P = 0.0318), and 8 weeks (P = 0.0047) compared to the control in the same period. PPD reduction at 4 weeks in test group was -1.67 ± 0.59 showing significant difference compared to the control (-1.37 ± 0.63, P = 0.0253). When teeth with mean PPD ≥5 mm were sorted, MGI decrease was significantly greater in test group at 1 (P=0.003) and 8 week (P=0.0102) follow-ups. PPD reduction was also significantly greater in test group at 4 week period (-1.98 ± 0.55 vs -1.58 ± 0.56, test vs control, P=0.0224).

CONCLUSIONS

Er,Cr:YSGG-assisted periodontal therapy is beneficial in MGI and PPD reductions during early healing period.

Photoinactivation and Photoablation of Porphyromonas gingivalis

Several types of phototherapy target human pathogens and Porphyromonas gingivitis (Pg) in particular. The various approaches can be organized into five different treatment modes sorted by different power densities, interaction times, effective wavelengths and mechanisms of action. Mode 1: antimicrobial ultraviolet (aUV); mode 2: antimicrobial blue light (aBL); mode 3: antimicrobial selective photothermolysis (aSP); mode 4: antimicrobial vaporization; mode 5: antimicrobial photodynamic therapy (aPDT). This report reviews the literature to identify for each mode (a) the putative molecular mechanism of action; (b) the effective wavelength range and penetration depth; (c) selectivity; (d) in vitro outcomes; and (e) clinical trial/study outcomes as these elements apply to Porphyromonas gingivalis (Pg). The characteristics of each mode influence how each is translated into the clinic.

Does photobiomodulation on the root surface decrease the occurrence of root resorption in reimplanted teeth? A systematic review of animal studies

This review aimed to answer the following question "Does photobiomodulation treatment of the root surface decrease the occurrence of root resorption in reimplanted teeth?" Electronic searches were performed in the MEDLINE/PubMed, Cochrane Library, Scopus, Web of Science, Embase, and Grey Literature Report databases. Risk of bias was evaluated using SYRCLE Risk of Bias tool. The Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) tool was used to assess the certainty of evidence. In total, 6 studies were included. Five studies reported a reduced occurrence of root resorption in teeth that received photobiomodulation treatment of the root surface prior to replantation. Only 1 study reported contradictory results. The photobiomodulation parameters varied widely among studies. GRADE assessment showed a low certainty of evidence. It can be inferred that photobiomodulation treatment of the root surface prior to replantation of teeth can reduce the occurrence of root resorption. Nonetheless, further clinical studies are needed.

Trial Registration

PROSPERO Identifier: CRD42022349891.

Impact exerted by scaffolds and biomaterials in periodontal bone and tissue regeneration engineering: new challenges and perspectives for disease treatment

The periodontium is an appropriate target for regeneration, as it cannot restore its function following disease. Significantly, the periodontium's limited regenerative capacity could be enhanced through the development of novel biomaterials and therapeutic approaches. Notably, the regenerative potential of the periodontium depends not only on its tissue-specific architecture and function but also on its ability to reconstruct distinct tissues and tissue interfaces, implying that the development of tissue engineering techniques can offer new perspectives for the organized reconstruction of soft and hard periodontal tissues. With their biocompatible structure and one-of-a-kind stimulus-responsive property, hydrogels have been utilized as an excellent drug delivery system for the treatment of several oral diseases. Furthermore, bioceramics and three-dimensional (3D) printed scaffolds are also appropriate scaffolding materials for the regeneration of periodontal tissue, bone, and cartilage. This work aims to examine and update material-based, biologically active cues and the deployment of breakthrough bio-fabrication technologies to regenerate the numerous tissues that comprise the periodontium for clinical and scientific applications.

Erbium-doped yttrium aluminum garnet laser and advanced platelet-rich fibrin+ in periodontal diseases: Two case reports and review of the literature

BACKGROUND

The goal of periodontal disease treatment is to completely remove bacteria and promote wound healing. The erbium-doped yttrium aluminum garnet (Er:YAG) laser is commonly used to treat periodontal disease. Advanced platelet-rich fibrin+ (A-PRF+) secrets growth factors that accelerates soft- and hard-tissue regeneration and wound healing. Herein I present 2 cases of patients with oral diseases treated with a combination of Er:YAG laser and A-PRF+.

CASE SUMMARY

Case 1 was a female with pocket depth bone loss over 8 mm and infection of tooth 31 and 41, and severe advanced periodontitis with grade III mobility. Case 2 was a male with tooth 22 root end apical swelling and infection and alveolar bony defects. Clinical outcomes were recorded at 6 and 36 mo. In case 1, the Er:YAG laser was used to perform open flap debridement (100 mJ/pulse, 15 Hz) and remove calculus and granulation tissue (50 mJ/pulse, 30 Hz). In case 2 the laser was used to create a semilunar full thickness flap incision (80 mJ/pulse, 20 Hz) and eliminate the pathogen (100 mJ/pulse, 15 Hz). In both patients, A-PRF+ mixed with bone was used to fill bone defects, and A-PRF+ autologous membranes were used to cover tension-free primary flaps. There was no recurrent infection at 36 mo, and tissue regeneration and would healing occurred.

CONCLUSION

Debridement with an Er:YAG laser followed by treatment with A-PRF+ is effective for the treatment periodontal diseases with bone defects.

The effect of Er,Cr:YSGG laser on periodontopathic bacteria elimination: an in vitro study

In vitro bacterial elimination using the erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser against periodontopathic bacteria was investigated. Bacterial suspensions of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis were spread on agar plates and the Er,Cr:YSGG laser was applied at 40 mJ pulse energy for durations of 30 s, 60 s, and 90 s. The agar plates were incubated, and growth inhibition zones were assessed. Optimal laser irradiation durations to achieve maximal bacterial elimination were evaluated using laser ablation on the bacterial colonies. The remaining viable bacteria were determined by the colony-forming unit (CFU) counting method. Growth inhibition zones were observed at all irradiation durations for both A. actinomycetemcomitans and P. gingivalis. Mean logarithmic values of CFU/ml after bacterial colony irradiation for 0 s (control), 12 s × 1 lap, 24 s × 1 lap, 48 s × 1 lap, and 24 s × 2 laps were 8.82 ± 0.35, 7.31 ± 0.94, 6.32 ± 0.61, 3.17 ± 2.90, and 0.00, respectively, for A. actinomycetemcomitans and 9.83 ± 0.50, 9.42 ± 0.11, 6.90 ± 1.60, 2.33 ± 3.19, and 0.00 for P. gingivalis. Significant differences were found between the control group and the two irradiated groups 48 s × 1 lap and 24 s × 2 laps (p < 0.05), and also between irradiated groups 12 s × 1 lap and 24 s × 2 laps (p < 0.05). An Er,Cr:YSGG laser with power setting 1.5 W and 30 Hz frequency showed potential for bacterial elimination against A. actinomycetemcomitans and P. gingivalis in vitro. Significant bacterial elimination (> 99.99%) was observed after 48 s of irradiation.

High-power laser for oral excisional biopsy in an oncologic patient with pancytopenia

Oral surgical procedures are a great challenge in cancer patients, especially those with pancytopenia, given the risk of both hemorrhage and opportunistic infection. Thus, we report herein a case of a patient with refractory acute myeloid leukemia, severe pancytopenia, and some episodes of febrile neutropenia, who presented asymptomatic, bilateral lesions on the tongue, requiring excisional biopsy. Considering the high risk of bleeding, surgical intervention was proposed with a high-power laser (HPL) at the bedside. There was no considerable bleeding and stitches were not needed. Within 48 h postoperatively, the patient reported neither pain nor further bleeding and her tongue presented normal function. The patient was under a follow-up period of about 8 months, with no lesion relapse. The HPL seems to be of great value for preventing excessive bleeding and late infection in patients with pancytopenia submitted to minor oral surgeries.

New Frontiers on Adjuvants Drug Strategies and Treatments in Periodontitis

Causes of the progression of periodontitis such as an imbalance between the immune response by the host by the release of inflammatory mediators in the response of the oral pathogenic dysbiotic biofilm have been identified. New insights on specific cell signaling pathways that appear during periodontitis have attracted the attention of researchers in the study of new personalised approaches for the treatment of periodontitis. The gold standard of non-surgical therapy of periodontitis involves the removal of supra and subgingival biofilm through professional scaling and root planing (SRP) and oral hygiene instructions. In order to improve periodontal clinical outcomes and overcome the limitations of traditional SRP, additional adjuvants have been developed in recent decades, including local or systemic antibiotics, antiseptics, probiotics, anti-inflammatory and anti-resorptive drugs and host modulation therapies. This review is aimed to update the current and recent evolution of therapies of management of periodontitis based on the adjunctive and target therapies. Moreover, we discuss the advances in host modulation of periodontitis and the impact of targeting epigenetic mechanisms approaches for a personalised therapeutic success in the management of periodontitis. In conclusion, the future goal in periodontology will be to combine and personalise the periodontal treatments to the colonising microbial profile and to the specific response of the individual patient.

Spherical submicron YAG:Ce particles with controllable particle outer diameters and crystallite sizes and their photoluminescence properties

The purpose of this study was to demonstrate the preparation of spherical submicron YAG:Ce particles with controllable particle outer diameters and crystallite sizes and their photoluminescence (PL) properties, which were produced using a flame-assisted spray-pyrolysis method followed by the annealing process. The correlation of particle outer diameter, crystallite size, and PL performance of the prepared particles was also investigated. Experimental results showed that the increases in the particle outer diameters have an impact on the obtainment of higher PL performance. Large particle outer diameters permitted the crystallites to grow more, whereas this is in contrast to the condition for small particle outer diameter having limitations in crystallite growth. This study also found that too large outer diameter (>557 nm) was not effective since crystallites cannot grow anymore and it permits possible scattering problems. This study provides significant information for optimizing synthesis parameters for controlling particle outer diameters and crystallite sizes, which could be relevant to other functional properties, especially for lens, solar cell, and LED applications.

Chronological Gene Expression of Human Gingival Fibroblasts with Low Reactive Level Laser (LLL) Irradiation

Though previously studies have reported that Low reactive Level Laser Therapy (LLLT) promotes wound healing, molecular level evidence was uncleared. The purpose of this study is to examine the temporal molecular processes of human immortalized gingival fibroblasts (HGF) by LLLT by the comprehensive analysis of gene expression. HGF was seeded, cultured for 24 h, and then irradiated with a Nd: YAG laser at 0.5 W for 30 s. After that, gene differential expression analysis and functional analysis were performed with DNA microarray at 1, 3, 6 and 12 h after the irradiation. The number of genes with up- and downregulated differentially expression genes (DEGs) compared to the nonirradiated group was large at 6 and 12 h after the irradiation. From the functional analysis results of DEGs, Biological Process (BP) based Gene Ontology (GO), BP ‘the defense response’ is considered to be an important process with DAVID. Additionally, the results of PPI analysis of DEGs involved in the defense response with STRING, we found that the upregulated DEGs such as CXCL8 and NFKB1, and the downregulated DEGs such as NFKBIA and STAT1 were correlated with multiple genes. We estimate that these genes are key genes on the defense response after LLLT.

Evaluation of the Efficacy of Ultrapulsed CO2 Laser in Chronic Wounds

BACKGROUND AND OBJECTIVES

Chronic wound repair is a major problem in wound treatment. Recently, several studies have suggested that carbon dioxide (CO₂ ) laser can be used to improve the healing of chronic wounds. The aim of the present study was to preliminarily investigate the efficacy of laser debridement in treating chronic wound through a comparison of traditional instrument/surgical debridement with the ultrapulsed CO₂ laser debridement in terms of wound healing, wound infection control, and wound blood perfusion.

STUDY DESIGN/MATERIALS AND METHODS

Patients with chronic wound admitted to the Wound Repair Clinic at The Affiliated Hospital of Southwest Medical University (Luzhou, China) between February 2019 and May 2019 were enrolled. They were randomly divided into two groups. The patients in one group were treated with traditional sharp instrument/surgical debridement (RT group; number of wounds: 28), while the patients in the other group were treated with ultrapulsed CO₂ laser debridement (LT group; number of wounds: 26). An intergroup comparison was performed based on parameters, such as wound healing, wound infection control, and changes in wound blood perfusion.

RESULTS

The wound healing rate and the total time to achieve healing were significantly better in the LT group versus the RT group at 7, 14, 21, and 28 days after treatment. The wound exudation scores were significantly higher in the LT group versus the RT group at 7, 14, and 28 days after treatment. The positive rate of pre-debridement bacterial culture was significantly lower in the LT group versus the RD group at 14 and 28 days after treatment. The percentage of wound perfusion/normal periwound skin perfusion was significantly higher in the LT group versus the RT group at 1, 7, and 14 days after treatment.

CONCLUSION

For the treatment of chronic refractory wounds, the ultrapulsed CO₂ laser exhibits higher accuracy, more effectively controls wound infection, promotes an increase in wound blood perfusion, and achieves faster wound healing compared with traditional sharp instrument/surgical debridement. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

Er:YAG Laser Irradiation Reduces Microbial Viability When Used in Combination with Irrigation with Sodium Hypochlorite, Chlorhexidine, and Hydrogen Peroxide

The erbium-doped yttrium aluminum garnet (Er:YAG) laser is used to treat periodontal disease; however, its effectiveness at killing oral bacteria is not well known. Furthermore, the compounding effect of the combination of a laser treatment and irrigation methods with antimicrobials on bacterial viability is yet to be determined. The purpose of this in vitro study was to evaluate the effect of the Er:YAG laser with irrigation using chlorhexidine (CHX), hydrogen peroxide (H₂O₂), or sodium hypochlorite (NaOCl) on the viability of oral bacteria. Three bacterial species were used in our study: Streptococcus gordonii, Fusobacterium nucleatum, and Porphyromonas gingivalis. Bacteria were grown in an anaerobic chamber in brain heart infusion broth and incubated at 37 °C. Bacterial samples with an OD of 0.5 were irradiated with the Er:YAG laser at 2940 nm using a 400-µm Varian tip. The experiment was repeated four times using these parameters: 40 mJ, 40 Hz, and 1.6 W for 20 seconds with the 300 µs short pulse duration in contact mode. Treatment groups consisted of the following: (1) no treatment, (2) 0.5% H₂O₂ alone, (3) 0.5% NaOCl alone, (4) 0.03% CHX alone, (5) Er:YAG irradiation alone, (6) Er:YAG irradiation with 0.5% H₂O₂, (7) Er:YAG irradiation with 0.5% NaOCl, and (8) Er:YAG irradiation with 0.03% CHX. Microbial viability was determined through plating and colony counts and calculated into CFU/ml. Statistical analysis was done using a two-tailed paired t-test. The use of the Er:YAG laser alone failed to show statistically significant antibacterial activity against any of bacteria. The most effective mono-treatment with irrigation solutions for all three bacteria were 0.5% H₂O₂ and 0.5% NaOCl (p < 0.001 for each solution). Irrigation with 0.03% CHX was most effective against F. nucleatum (p < 0.01) and less against P. gingivalis and S. gordonii and showed the least antibacterial action alone but improved significantly in combination therapy (p < 0.05). The combined treatment with the Er:YAG showed the greatest and most significant improvement in the reduction of bacterial viability compared to any other treatment group (p < 0.05 for each combined treatment). Irradiation with the Er:YAG laser with the addition of 0.5% H₂O₂, 0.5% NaOCl, or 0.03% CHX under a short working time (20 s) resulted in a significant reduction of bacterial viability for all three bacterial species compared with any single treatment option. The combination of irradiation with the Er:YAG laser with the addition of 0.5% H₂O₂, 0.5% NaOCl, or 0.03% CHX resulted in a larger reduction of bacterial survival when compared to monotherapies with antimicrobial solutions or laser. The combination of the Er:YAG laser with a low concentration irrigant solution of 0.5% H₂O₂, 0.5% NaOCl, or 0.03% CHX could be an effective treatment protocol for the reduction of periodontal pathogens and thus suitable treatment for non-surgical periodontal therapy.

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.

Efeitos do laser de diodo de alta potência e da fotobiomodulação em dentes de ratos reimplantados tardiamente

Resumo Introdução A busca por protocolos efetivos para reduzir a incidência de reabsorções radiculares e favorecer a reparação do ligamento periodontal perdido ainda representa um grande desafio, tendo em vista o prognóstico desfavorável dos reimplantes dentais tardios. Objetivo Avaliar, por meio da análise histológica, os efeitos do laser de alta potência e da fotobiomodulação na ocorrência de reabsorção radicular e no reparo periodontal, em dentes reimplantados tardiamente. Material e método Foram utilizados 50 incisivos centrais direitos de ratos Wistar. Após a extração, os espécimes foram divididos em cinco grupos (n = 10): G1 (controle positivo): reimplante imediato; G2 (controle negativo): reimplante tardio (RT): espécimes mantidos em ambiente seco por 60 minutos, sem tratamento adicional; G3: RT associado ao tratamento da superfície radicular com laser diodo de alta potência (810 nm, 1.5 W); G4: RT + superfícies radiculares e feridas alveolares tratadas com fotobiomodulação (laser diodo 660 nm, 30 mW e 780 nm, 40 mW, respectivamente); G5: RT + superfícies radiculares irradiadas com laser de alta e alvéolos com fotobiomodulação, nos mesmos parâmetros que G3 e G4, respectivamente. Após 60 dias, os animais foram eutanasiados. Os espécimes foram processados para análise histológica. Resultado G3 e G5 apresentaram as menores médias de scores com relação à ocorrência de reabsorções radiculares e anquilose, quando comparados a G2 e G4 (Teste Kruskall-Wallis, p<0,05). Com relação ao reparo periodontal, todos os grupos experimentais (G3, G4 e G5) apresentaram médias de escores inferiores (Teste Kruskall-Wallis, p<0,05) comparadas ao G1 e semelhantes ao G2 (Teste Kruskall-Wallis, p>0,05). Conclusão O laser de alta potência, associado ou não à fotobiomodulação, diminuiu a ocorrência das reabsorções radiculares e da anquilose, e a fotobiomodulação não favoreceu o controle das reabsorções radiculares nem o reparo periodontal.

Laser reduction of specific microorganisms in the periodontal pocket using Er:YAG and Nd:YAG lasers: a randomized controlled clinical study

The objective of this study was to evaluate the microbiological and clinical outcomes following nonsurgical treatment by either scaling and root planing, combination of Nd:YAG and Er:YAG lasers, or by Er:YAG laser treatment alone. The study involved 60 patients with generalized chronic periodontitis, randomly assigned into one of three treatment groups of 20 patients. The first group received scaling and root planing by hand instruments (SRP group), the second group received Er:YAG laser treatment alone (Er group), and the third group received combined treatment with Nd:YAG and Er:YAG lasers (NdErNd group). Microbiological samples, taken from the periodontal pockets at baseline and 6 months after treatments, were assessed with PET Plus tests. The combined NdErNd laser (93.0%), followed closely by Er:YAG laser (84.9%), treatment resulted in the highest reduction of all bacteria count after 6 months, whereas SRP (46.2%) failed to reduce Treponema denticola, Peptostreptococcus micros, and Capnocytophaga gingivalis. Full-mouth plaque and bleeding on probing scores dropped after 6 months and were the lowest in both laser groups. The combination of NdErNd resulted in higher probing pocket depth reduction and gain of clinical attachment level (1.99 ± 0.23 mm) compared to SRP (0.86 ± 0.13 mm) or Er:YAG laser alone (0.93 ± 0.20 mm) in 4-6 mm-deep pockets. Within their limits, the present results provide support for the combination of Nd:YAG and Er:YAG lasers to additionally improve the microbiological and clinical outcomes of nonsurgical periodontal therapy in patients with moderate to severe chronic periodontitis.

Comparison of clinical parameters, microbiological effects and calprotectin counts in gingival crevicular fluid between Er: YAG laser and conventional periodontal therapies: A split-mouth, single-blinded, randomized controlled trial

BACKGROUND

The erbium-doped yttrium, aluminum, and garnet (Er:YAG) laser is thought to be the most promising laser for periodontal treatment; however, its application is still under consideration. The aim of this study was to compare Er:YAG laser monotherapy with conventional scaling and root planing (SRP) for chronic periodontitis using clinical parameters, the detection rate of periodontal pathogens, and the calprotectin level in gingival crevicular fluid.

METHODS

Twenty-seven participants with moderate-to-advanced chronic periodontitis were included. In a split-mouth design, the 2 half-mouths of each participant were randomly assigned to Er:YAG laser or SRP (combination of ultrasonic and manual instruments) treatment. Clinical parameters were recorded at baseline, 6 weeks, and 3 and 6 months after treatment. At the same time points, gingival crevicular fluid was collected to analyze the detection rate of 6 periodontal pathogens by polymerase chain reaction and the levels of calprotectin by enzyme-linked immunosorbent assay.

RESULTS

Both treatment groups showed significant reductions in probing depth (PD), bleeding index (BI), and clinical attachment level (CAL) from baseline to 6 months. For sites with 4 mm ≤ PD ≤ 6 mm at baseline, SRP resulted in a greater reduction in PD and CAL than Er:YAG laser treatment, and the difference remained at 6 months post-treatment (P = .01 and P < .01, respectively). For sites with PD ≥7 mm at baseline, the clinical parameters showed similar results between the 2 groups. SRP resulted in a lower detection rate of Porphyromonas gingivalis at 6 months post-treatment. The levels of calprotectin were significantly decreased from baseline to 6 months in both groups, without a significant difference between the groups.

CONCLUSION

For mild pockets, conventional SRP may still be the preferred choice. For deep pockets, Er:YAG laser treatment could be an effective alternative. Studies are needed to explore more advanced instruments and new application methods for the Er:YAG laser for periodontal treatment in deep pockets.

In Vitro-Activity of Er:YAG Laser in Comparison with other Treatment Modalities on Biofilm Ablation from Implant and Tooth Surfaces

BACKGROUND AND AIM

Bacterial biofilms play a major role in the etiology of periodontal and peri-implant diseases. The aim of the study was to evaluate the removal of bacterial biofilms and attachment of epithelial cells (EC), gingival fibroblasts (GF) and osteoblast-like cells (OC) to dentin and titanium surfaces after Er:YAG laser (Er:YAG) in comparison with other treatment methods.

MATERIAL AND METHODS

Multi-species bacterial biofilms were grown on standardized dentin and titanium specimens with a sand-blasted and acid etched (SLA) surface for 3.5 d. Thereafter, the specimens were placed into artificially-created pockets. The following methods for biofilm removal were used: 1) Gracey (dentin) or titanium curettes (CUR), 2) Er:YAG, 3) photodynamic therapy (PDT) and 4) CUR with adjunctive PDT (CUR/PDT). Colony forming units (CFUs) of the remaining biofilms and attachment of EC, GF and OC were determined. Statistical analysis was performed by means of ANOVA with post-hoc LSD.

RESULTS

All treatment methods decreased statistically significantly (p<0.001) total CFUs in biofilms compared with untreated dentin and titanium surfaces respectively. On dentin, Er:YAG was equally efficient as CUR and PDT but inferior to CUR/PDT (p = 0.005). On titanium, surfaces, the use of Er:YAG resulted in statistically significantly superior biofilm removal compared to the 3 other treatments (each p<0.001). Counts of attached EC, GF and OC were the lowest on untreated contaminated dentin and titanium surfaces each. After CUR/PDT higher EC counts were found on dentin (p = 0.006). On titanium, all decontamination methods statistically significantly increased (p<0.001) the counts of attached EC without differences between groups. Statistically significantly higher counts of GF (p = 0.024) and OC (p<0.001) were observed after Er:YAG decontamination compared with untreated surfaces.

CONCLUSION

Ablation of subgingival biofilms and in particular decontamination of titanium implant surfaces with an Er:YAG laser seem to be a promising approach and warrants further investigations.

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.

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.

In Vitro Study of Temperature Changes in Pulp Chamber During Root Planing Procedure Using Er:YAG Laser

AIM

To assess temperature changes at specified time intervals during Er:YAG laser scaling and root planing of surfaces with dental calculus.

MATERIALS AND METHODS

Fifteen single-rooted teeth with advanced periodontal disease were extracted and fixed in a cylinder thermostat filled with distilled water at constant temperature (35.5°C). A specially designed thermal probe (type K thermocouple) accurate to ±0.1°C over the range from 20°C to 80°C was fitted into the pulp chamber of tooth sample. Scaling and root planing of the mesial and distal root surfaces was performed using an Er:YAG laser (Lite Touch, Syneron Dental, Israel) with a wavelength of 2940 nm, provided with a chisel tip, and at the following settings: output energy 100 mJ and 50 Hz, duration of irradiation - 40 sec, the tip in contact mode oblique to the root surface at an angle of approximately 10-15 degrees and water spray level 5-6. The temperature inside the pulp chamber was measured every 10 sec.

RESULTS

The temperature in the pulp chamber taken every 10 seconds and compared with the temperature of 35.5°C at baseline decreased by 1.6°C, 2.4°C, 2.5°C, and 2.5°C for the first, second, third and fourth measurement, respectively. These changes did not reach statistical significance.

CONCLUSION

The Er:YAG laser does not increase the temperature inside the pulp chamber. The assessed changes do not depend on the duration of irradiation which was kept within 40 seconds. Therefore, this treatment modality causes no thermal damage to the pulp under the above defined conditions and can be considered safe.

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.

Root Surface Bio-modification with Erbium Lasers- A Myth or a Reality??

The objective of this literature review was to critically review the evidence available in the literature regarding the expediency of erbium family of lasers for root bio modification as a part of periodontal therapy. The literature search was performed on the Pubmed using MeSH words such as "lasers/therapeutic use, scaling, dental calculus, tooth root/anatomy and histology, ultrasonic therapy". The studies were screened and were grouped as follows: those evaluating a) efficacy for calculus removal with the Erbium family of laser b) root surface changes following Er YAG and Er Cr YSGG application c) comparative studies of the Er YAG, Er Cr YSGG lasers versus conventional methods of root surface modification d) Bio compatibility of root surface following Erbium laser treatment e) Studies on the combined efficacy of laser root modification with conventional methods towards root surface bio-modification f) Studies on effectiveness of root surface bio-modification prior to root coverage procedures. In conclusion, the erbium family has a proven anti-bacterial action, predictable calculus removal, minimal root substance removal, and appears to favor cell attachment. The Erbium family of lasers appears to be a useful adjunct for the management of periodontal disease.

Effect of Er,Cr:YSGG laser application in the treatment of experimental periodontitis

The purpose of this study was to evaluate the influence of an erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser in the absence or presence of manual scaling and root planning (SRP) for the treatment of induced periodontitis in rats. Ligatures were placed in the subgingival region of the maxillary first molar. After a 7-day period, the ligatures were removed, and 40 rats were randomly divided into four groups (G), as follows: (GI) no treatment, (GII) scaling and root planning (SRP) with curettes, (GIII) Er,Cr:YSGG laser irradiation and (GIV) SRP with curettes followed by Er,Cr:YSGG laser irradiation. Seven and 30 days after the treatment, the animals were sacrificed and histologic, histometric and immunohistochemistry analyses were performed. All groups showed similar histopathological characteristics during the evaluation period. The histometric analysis was confirmed using Bonferroni and paired t tests. At 7 and 30 days, groups II, III and IV exhibited greater bone formation in the furcation area when compared to group I (p < 0.0001; p < 0.05). During the 7-day period, the groups irradiated with the laser (III and IV) showed a statistically larger new bone area than the group treated with SRP (II) (p < 0.01). Immunohistochemistry analysis revealed that the control group exhibited a higher expression of tartrate-resistant acid phosphatase (TRAP) and the receptor activator of nuclear factor κΒ ligand (RANKL) when compared to groups II, III and IV (p < 0.05). All treatments were able to reduce the inflammatory processes, consequently enabling the repair of periodontal tissues. The results achieved with the application of the Er,Cr:YSGG laser suggest that this laser can stimulate greater bone formation, especially over a shorter period of time.

Initial fibroblast attachment to Erbium:YAG laser-irradiated dentine

AIMS

To evaluate the effects of Erbium (Er):YAG laser irradiation on the morphology of resected dentine surfaces, and to investigate fibroblast attachment to laser-irradiated dentine surfaces.

METHODOLOGY

Dentine blocks obtained from single-rooted human teeth were divided into the following groups after sterilization in an autoclave: (i) Laser group treated with Er:YAG laser irradiation (30 mJ per pulse, 10 pps, 60 s); (ii) L-MTAD group treated with laser irradiation as in (i) plus a mixture of doxycycline, tetracycline isomer and citric acid; (iii) RC-Prep group treated with EDTA gel or cream (RC-Prep) and (iv) Control group left untreated. After each treatment, the dentine blocks were incubated with NIH/3T3 fibroblasts cultured to subconfluency in Dulbecco's modified Eagle's medium supplemented with 10% foetal bovine serum and antibiotics. The number of attached cells amongst the groups was analysed statistically at the 5% significance level. The dentine surface morphologies and cell attachments were evaluated by counting assays, histological observations and scanning electron microscopy (SEM).

RESULTS

The number of attached cells was significantly higher (P < 0.05) in the Laser group than in the RC-Prep and Control groups at 16 h. Dendritic cell extension of the fibroblasts was only observed in the Laser group at 8 h by SEM. In the histological analyses, significantly more attached cells were found on the dentine surfaces treated with laser irradiation.

CONCLUSIONS

Er:YAG laser irradiation induced morphological alterations in dentine surfaces, which may improve the attachment of fibroblasts to dentine.