Enhanced Recovery of Local Anesthesia in Pediatric Patients: The Impact of Photobiomodulation on Reversing Anesthesia Effects

BACKGROUND The split-mouth study design is used in oral health research and usually consists of 2 treatments randomly assigned to either the right or left side. This split-mouth study aimed to evaluate the efficacy of photobiomodulation on reversal of local anesthesia in 50 children aged 8-10 years. MATERIAL AND METHODS The study was conducted among 50 children: 27 girls and 23 boys, aged 8-10 years (mean age 9.38±1.15 years), who presented 2 carious maxillary permanent molars. One side was randomly assigned to the laser group (50 teeth), and the contralateral side to the control group (50 teeth). At the end of the treatment, photobiomodulation (PBM) was performed in the area of infiltration at 6 points, with 635 nm (25 children) (250 mW, 500 mW/cm², 15J) and 808 nm (25 children) (200 mW, 400 mW/cm², 12J) (SmartM PRO, Lasotronix, Poland). On the contralateral side, the laser's off-mode applicator was used. Anesthetic effect was evaluated by palpation test (soft tissues) and electrical test (dental pulp). RESULTS After 15 minutes, in the laser group the return to normal sensations in the palpation test showed 88% (808 nm) and 68% (635 nm), and only 20% in the control group (P=0.04123). After 45 minutes, all the participants from the PBM group returned to normal sensations (P=0.21458). Dental pulp's excitability threshold was lower for both wavelengths compared to the control group (P=0.000001). CONCLUSIONS The identification of factors accelerating the recovery time to normal function, such as PBM, can be used as important data to eliminate self-injury secondary to local anesthesia (LA) in children.

A Molecular Approach for Detecting Bacteria and Fungi in Healthcare Environment Aerosols: A Systematic Review

Molecular methods have become integral to microbiological research for microbial identification. This literature review focuses on the application of molecular methods in examining airborne bacteria and fungi in healthcare facilities. In January 2024, a comprehensive electronic search was carried out in esteemed databases including PubMed, Web of Science, and Scopus, employing carefully selected keywords such as ((bacteria) OR (virus) OR (fungi)) AND (aerosol) AND ((hospital) OR (healthcare) OR (dental office)) AND ((molecular) OR (PCR) OR (NGS) OR (RNA) OR (DNA) OR (metagenomic) OR (microarray)), following the PRISMA protocol. The review specifically targets healthcare environments with elevated concentrations of pathogenic bacteria. A total of 487 articles were initially identified, but only 13 met the inclusion criteria and were included in the review. The study disclosed that the prevalent molecular methodology for appraising aerosol quality encompassed the utilization of the PCR method, incorporating either 16S rRNA (bacteria) or 18S rRNA (fungi) amplification techniques. Notably, five diverse molecular techniques, specifically PFGE, DGGE, SBT, LAMP, and DNA hybridization methods, were implemented in five distinct studies. These molecular tests exhibited superior capabilities compared to traditional bacterial and fungal cultures, providing precise strain identification. Additionally, the molecular methods allowed the detection of gene sequences associated with antibiotic resistance. In conclusion, molecular testing offers significant advantages over classical microbiological culture, providing more comprehensive information.

Red/Orange Autofluorescence in Selected Candida Strains Exposed to 405 nm Laser Light

BACKGROUND

Candida albicans and similar species are significant pathogens in immunocompromised and hospitalized individuals, known for mucosal colonization and bloodstream/organ invasion. Many pathogenic fungi, including these species, exhibit autofluorescence (R/OF) under specific light conditions, a feature crucial for their detection.

AIM

We investigated the use of a 405 nm diode laser for the direct observation of red/orange autofluorescence of Candida spp., common in the oral cavity, exploring its potential in health screenings.

METHODS

This study utilized cultures of Candida spp. on Sabouraud dextrose agar with Qdot 655 and 685 for fluorescence benchmarking, illuminated using a 405 nm diode laser (continuous wave, power 250 mW, 0.0425 J/cm² fluence, 0.0014 W/cm² power density). Images were captured using a yellow-filter camera at set intervals (48 to 144 h). Visual and computational analyses evaluated the R/OF in terms of presence, intensity, coloration, and intra-colony variation.

RESULTS

Most Candida strains displayed red/orange autofluorescence at all observation times, characterized by varied coloration and intra-colony distribution. Initially, there was an increase in R/OF intensity, which then stabilized in the later stages of observation.

CONCLUSIONS

The majority of the Candida strains tested are capable of emitting R/OF under 405 nm laser light. This finding opens up new possibilities for integrating R/OF detection into routine dental screenings for Candida spp.

Analysis of aerosol generation during Er:YAG laser-assisted caries treatment: A randomized clinical trial

BACKGROUND

Maintaining biosafety in dental practice involves the effective elimination of aerosols produced during dental treatment.

OBJECTIVES

To assess the quantity of aerosols and aerobic bacteria in the air during the treatment of caries.

MATERIAL AND METHODS

The study involved 60 patients with a total of 60 molar teeth (n = 60) in the mandible who were divided into 2 groups based on caries treatment method. Group 1 (G1, n = 30) received treatment with a conventional dental turbine (W&H Synea TA-98LC; W&H, Burmoos, Austria), while group 2 (G2, n = 30) underwent treatment with an Er:YAG (erbium-doped yttrium aluminium garnet) laser (LightWalker, Fotona, Slovenia). Measurements of aerosol particles between 0.3 Ęm and 10.0 Ęm near the operatorfs mouth were taken using the PC200 laser particle counter (Trotec GmbH, Schwerin, Germany). The number of aerobic bacteria in the air was determined using 60 Petri plates with a microbiological medium (Columbia agar with 5% sheep blood) and the sedimentation method. A control group (G3) was established to measure initial aerosol levels and initial total number of bacteria colony-forming units (CFUs) before each treatment.

RESULTS

In G1 (dental turbine), the median value of aerosol particles was 57,021 (42,564.67,568), while in G2 (Er:YAG laser), it was significantly lower at 33,318 (28,463.35,484) (p < 0.001). The median total bacteria count per cubic meter of air in G1 (conventional dental turbine + high volume evacuator (HVE)), G2 (Er:YAG laser + HVE) and G3 (control group before caries treatment) were 734 (420.988), 158 (96.288) and 48 (32.74), respectively, with a statistically significant difference between the groups (p < 0.001).

CONCLUSIONS

The use of Er:YAG laser during caries treatment resulted in a 41.6% reduction in aerosol amounts and a 78.5% decrease in the total bacterial count (TBC) compared to treatment with a dental turbine.

The Impact of Hydrogen Peroxide (H2O2) Fumigation on Bacterial Levels in Dental Office Environments: A Randomized Clinical Trial Investigation

BACKGROUND

Fumigation with hydrogen peroxide has proven to be a highly effective approach to maintaining biological safety within dental offices. The main purpose of this research was to investigate the efficacy of hydrogen peroxide (H2O2) fumigation in reducing bacterial levels in dental office environments.

METHODS

The study involved 30 participants diagnosed with moderate caries decay (ICDAS 3 and 4) in their mandibular molars. Sixty Petri dishes (two per patient) with Columbia Agar and 5% Sheep Blood were opened at the beginning of the caries treatment. After the completion of caries treatment and tooth restoration, 30 plates (G1 group) were closed. Following this, a 20 min fumigation procedure with 6% hydrogen peroxide biosanitizer using a compressed air device was conducted. After the fumigation, the remaining plates were closed (G2 group). The total number of bacteria CFUs (colony-forming units) in the dental office air was determined using the Koch sedimentation method.

RESULTS

The total bacterial colony (TBC) level, measured in cfu/m3, demonstrated a significant decrease in the number of bacteria following room environment fumigation (163.1 ± 145.7; G2 group) compared to non-fumigated samples (817.2 ± 208.2; G1 group) (p < 0.001). The predominant bacteria observed in the microbiological plates before fumigation were Micrococcus and Bacillus species, found in 80% (24/30) and 60% (18/30) of the plates, respectively. Application of H2O2 room fumigation resulted in a significant reduction in bacterial numbers: 79.2% (5/30) for Micrococcus species (p < 0.001), 83.3% (3/30) for Bacillus species (p < 0.001), and 100% (0/30) for Staphylococcus arlettae (p < 0.05).

CONCLUSION

Fumigation with 6% H2O2 is an effective method for reducing bacterial counts in a dental office environment.

Diagnosis, management and knowledge of halitosis among Polish and Lebanese dentists: Questionnaire-based survey

BACKGROUND

Halitosis (fetor ex ore, malodor, bad breath) is defined as an unpleasant odor coming from the oral cavity, regardless of the cause: local or systemic. It affects 22-50% of the population worldwide, leading to a significant decrease in the overall quality of life, and can have oral and extra-oral etiologies. There is an increased interest in the management of halitosis.

OBJECTIVES

This study aims to evaluate the patient-dentist communication on halitosis, the dentists' knowledge about the management and etiology of halitosis, and the treatment options used by dentists who practice in Poland and Lebanon.

MATERIAL AND METHODS

An online questionnaire was sent to both Lebanese and Polish dentists using Google Forms (Google LLC, Mountain View, USA). In total, 205 dentists completed the questionnaire, of which 100 practiced in Poland (group P) and 105 practiced in Lebanon (group L). A multivariate analysis was conducted to determine differences between both groups and to identify parameters that could influence a dentist's management of halitosis.

RESULTS

According to the questionnaire, 86% of group P members and 65.7% of group L members reported communicating with patients about halitosis. Regarding the knowledge of halitosis, 78% of dentists in group P and 85.7% of dentists in group L reported that there is a classification for halitosis. A significant majority of dentists in both groups revealed not having any tool to measure halitosis (67.6% and 68% from group P and group L, respectively).

CONCLUSIONS

This study confirms the need for improved communication skills in Polish and Lebanese dentists, as well as for education on the subject among dentists in both countries, and for standardization in diagnosis, treatment modalities and management of halitosis.

Viability of bacteria associated with root caries after Nd:YAG laser application in combination with various antimicrobial agents: An in vitro study

BACKGROUND

The neodymium-doped yttrium aluminum garnet (Nd:YAG) laser has various therapeutic applications in dentistry, including the treatment of dentin hypersensitivity and the bacterial reduction therapy in periodontology. The addition of antimicrobial agents may enhance the impact of the laser on bacterial viability.

OBJECTIVES

This in vitro study aimed to assess the effect of Nd:YAG laser application in combination with various chemical antimicrobial agents, including hydrogen peroxide (H2O2), sodium hypochlorite (NaOCl), chlorhexidine (CHX), and sodium fluoride (NaF), on the viability of bacteria implicated in the etiology of root caries.

MATERIAL AND METHODS

Three oral bacterial species were examined: Streptococcus mutans (S. mutans); Streptococcus sanguinis (S. sanguinis); and Enterococcus faecalis (E. faecalis). The bacteria were grown in broth at 37°C, and then treated with the chemical agents and/or irradiated with an Nd:YAG laser for 30 s. Each treatment modality was repeated 3 times: group 1 - no treatment; group 2 - 0.5% H2O2; group 3 - 0.5% NaOCl; group 4 - 0.12% CHX; group 5 - 2% NaF; group 6 - Nd:YAG laser irradiation; group 7 - laser and 0.5% H2O2; group 8 - laser and 0.5% NaOCl; group 9 - laser and 0.12% CHX; and group 10 - laser and 2% NaF. The viability of the bacteria was determined by plating them, counting viable colonies, converting the data into colony-forming units (CFUs)/mL, and transforming them into the log form. Statistical analysis was performed using the two-tailed paired t test.

RESULTS

Irradiation with an Nd:YAG laser alone did not show a statistically significant effect against any of the bacterial species. The only effective antimicrobial used alone was CHX for S. mutans. Chlorhexidine with Nd:YAG resulted in a greater reduction in S. mutans and E. faecalis than either treatment alone. Meanwhile, H2O2 with Nd:YAG also showed an enhanced S. mutans reduction. Treatment with 0.5% NaOCl in conjunction with Nd:YAG brought the most significant reduction in viability for all bacteria in comparison with other treatment modalities.

CONCLUSIONS

The Nd:YAG laser combined with 0.5% NaOCl resulted in the most substantial reduction in bacterial survival as compared to the antimicrobials or the Nd:YAG laser used alone.

Photodynamic Therapy with Tolonium Chloride and a Diode Laser (635 nm) in the Non-Surgical Management of Periodontitis: A Clinical Study

This study aimed to evaluate the efficacy of photodynamic therapy (PDT) using tolonium chloride and a 635 nm diode laser as an adjunct to non-surgical periodontitis treatment, specifically scaling and root planing (SRP) alone. A total of 32 patients with a pocket probing depth > 5 mm were included in the study. Among them, 16 patients underwent SRP alone (control group), and the remaining 16 patients received SRP along with PDT (study group). The PDT procedure utilized a 635 nm diode laser (Smart M, Lasotronix, Poland) and tolonium chloride. Clinical periodontal parameters, such as the plaque index (PI), bleeding on probing (BOP), gingival recession (GR), probing pocket depth (PPD), and clinical attachment loss (CAL), were assessed before treatment (T0) and at 3 months after treatment (T3). At T3, both groups demonstrated a significant reduction in the PI, BOP, PD, and CAL compared to T0. The SRP + PDT group displayed a significant reduction in PPD (3.79 mm ± 0.35) compared to the SRP alone group (4.85 mm ± 0.42) at T3. Furthermore, the SRP + PDT group exhibited a significant reduction in CAL (5.01 ± 0.81) compared to the SRP group (5.99 ± 1.08) at T3. Within the study's limitations, it was concluded that PDT, with tolonium chloride and a 635 nm diode laser, significantly contributed to the non-surgical treatment of periodontitis.

Quantitative Evaluation of Aerosols Produced in the Dental Office during Caries Treatment: A Randomized Clinical Trial

BACKGROUND

Effective removal of aerosols generated during dental treatment is crucial for maintaining biosafety in dental practice. This study aimed to measure the aerosol amount and the number of aerobic bacteria in the air during caries treatment.

METHODS

The study involved 50 molar teeth (n = 50) in the mandible in 50 patients divided into two groups based on the type of a high-volume evacuator (HVE); G1 (n = 25) conventional HVE (EM19 EVO, Monoart^® Euronda, Vicenza, Italy) and G2 (n = 25) a new, wider, customized HVE. The PC200 laser particle counter (Trotec GmbH, Schwerin, Germany) was used to measure aerosol particles in a range of 0.3-10.0 μm near the operator's mouth. The study used 60 microbiological plates with a microbiological medium (Columbia Agar with 5% Sheep Blood) to check the number of aerobic bacteria in the air.

RESULTS

The mean value of aerosol particles in the G1 group (conventional HVE) was 54,145 ± 7915, while in the G2 group (test, wider evacuator) was lower and amounted to 32,632 ± 1803. (p < 0.001). The median total bacteria count in the air per cubic meter in control, G1 (HVE), and G2 (NEW-HVE) groups were 50 [36-60]; 772 [643-881]; 120 [92-139], respectively. (p < 0.05). Gram-positive cocci were the predominant bacteria in the plates: Micrococcus sp. (50%), Bacillus species (36.4%), Staphylococcus epidermidis (3.8%), Staphylococcus saprophyticus (3.8%).

CONCLUSIONS

the application of the wider high-volume evacuator increases the air purity during caries treatment as well as the biological safety of a dental office.

Erbium laser-assisted ceramic debonding: a scoping review

PURPOSE

Removal of ceramic restorations and appliances can be time consuming, invasive, and inconvenient. Erbium lasers offer an alternative noninvasive method for debonding of ceramic appliances. This paper aims to provide a comprehensive review of current literature on the effectiveness of erbium lasers for removal of ceramic restorations and appliances from natural teeth and dental implants.

METHODS

A comprehensive search of 7 databases, including Medline (Ovid), Embase, Dentistry and Oral Sciences Source (DOSS), Web of Science, Cochrane Library, and ProQuest Dissertations and Theses was performed. The inclusion and exclusion criteria were agreed prior to the literature search. Two reviewers independently screened the title and abstract. A third reviewer then broke the tie, if any. The selected articles then underwent full text review and the data was extracted.

RESULTS

The search identified 4117 unique articles published through June 10, 2021. Studies were assessed and categorized based on the type of restoration/appliance, type of abutment, type of laser, laser settings, efficacy of debonding, and pulpal temperature rise. Thirty-eight full-text articles were reviewed for inclusion. Time for ceramic debonding varies depending on the type of restorations and materials. Removal of zirconia crowns from teeth and implant abutments requires a longer period of time compared to lithium disilicate crowns. Temperature increases were reported as 5.5 degrees or less. Laser setting and laser type affect the debonding time and the increase in temperature. Examinations of debonded ceramics demonstrated no known structural damages resulting from laser applications.

CONCLUSIONS

Erbium lasers are effective noninvasive tools to remove all ceramic restorations/appliances from natural teeth and implant abutments without causing harm to abutments. Laser-assisted debonding should be considered as a viable alternative to rotary instrumentation for ceramic crowns; however, clinical studies of erbium-assisted ceramic retrieval are needed.

Effectiveness of lasers and aPDT in elimination of intraoral halitosis: a systematic review based on clinical trials

In recent years, there has been increasing interest in research showing positive results in antimicrobial photodynamic therapy (aPDT) and laser therapy (LT) in dentistry. The authors of this review tried to answer the question: “Is the effectiveness of lasers and aPDT in the elimination of intraoral halitosis possible?” For this purpose, the electronic database of PubMed and Cochrane Library were searched until September 2021 using a combination of different keywords: (bad breath OR fetor ex ore OR halitosis OR oral malodor) AND (laser OR PDT OR PACT OR photodynamic inactivation OR photodynamic therapy OR photodynamic antimicrobial chemotherapy). Initially, 83 studies were identified. A total of 9 articles were qualified after the application of the eligibility criteria. Eight works concerned aPDT treatment, and only one dedicated to the Er,Cr:YSGG laser. A significant reduction in halitosis occurred immediately after both LT and aPDT. The review found the confirmation of the effectiveness of laser therapy in reducing the number of volatile sulfur compounds (VSC) and the amount of anaerobic bacteria responsible for VSC formation. In most studies, a positive effect was observed for a 1-week follow-up. Laser therapy (aPDT, Er,Cr:YSGG) effectively eliminates microorganisms that produce volatile compounds and can effectively eliminate bad breath for the longer period of time than traditional methods of combatting this ailment.

Efficacy of the Adjunct Use of Povidone-Iodine or Sodium Hypochlorite with Non-Surgical Management of Periodontitis: A Systematic Review and Meta-Analysis

This systematic review sought to assess the efficacy of combining either sodium hypochlorite or povidone-iodine as disinfection solutions with non-surgical treatment of periodontitis. An electronic search was conducted through PubMed, Scopus, Web of Science, CENTRAL, and Google Scholar from inception until 10 September 2022. Outcomes included clinical outcomes (probing pocket depth, plaque index, clinical attachment level, relative-horizontal attachment level, bleeding on probing, gingival recession, the position of gingival margin) and biochemical (BAPNA level) properties. A subgroup analysis was conducted according to the assessment timepoint. Ten studies reporting the use of povidone-iodine and five studies reporting the use of sodium hypochlorite were included in this review. Overall, in the meta-analysis of povidone-iodine, no significant changes were noted in any of the assessed outcomes; however, minor changes were noted in probing pocket depth and clinical attachment level at a specific timepoint. Regarding sodium hypochlorite, a significant reduction in all clinical outcomes, except for bleeding on probing, was noted. In conclusion, the use of povidone-iodine does not result in an improvement in clinical outcomes, whereas sodium hypochlorite has promising properties that result in significant improvement in probing pocket depth and clinical attachment level. However, more studies are needed to confirm these observations.

Sodium Hypochlorite and Diode Laser in Non-Surgical Treatment of Periodontitis: Clinical and Bacteriological Study with Real Time Polymerase Chain Reaction (PCR)

Increasing the disinfection during non-surgical treatment of periodontitis is primordial. This study assesses the effectiveness of sodium hypochlorite and a 980 nm diode laser in non-surgical treatment of periodontitis. Thirty sites of localized periodontitis with a probing pocket depth (PPD) of ≥ 6 mm were included. Fifteen underwent scaling root planing (SRP group) and 15 underwent SRP + 0.5% NaOCl and a 980 nm diode laser (study group). A biological molecular test and real time polymerase chain reaction (RT-PCR) were performed before (T0) and after intervention (T1). Total bacterial count and counts of Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, Prevotella intermedia, Peptostreptococcus micros, Fusobacterium nucleatum, Aggregatibacter actinomycetemcomitans, Eubacterium nodatum, Capnocytophaga gingivalis were assessed. Plaque index (PI), bleeding on probing (BOP), gingival recession (GR), PPD and clinical attachment loss (CAL) were evaluated at T0, and 3 and 6 months after. Study group showed a statistically significant reduction of TBC (5.66 × 10⁸ CFU/mL) compared to SRP (6.2 × 10⁹ CFU/mL). Both groups showed a statistically significant reduction of Treponema denticola, Tannerella forsythia, Prevotella intermedia, Peptostrep. (micromonas) micros and Fusobacterium nucleatum; however, a significant reduction of Eubacterium nodatum and Capnocytophaga gingivalis was observed in the study group. At T6, both groups had a statistically significant reduction of PI, BOP, GR, PD and CAL. The study group showed more GR compared to SRP and a significant reduction of PD (4.03 mm ± 0.49) compared to SRP (5.28 mm ± 0.67). This study reveals that NaOCl and a diode laser are effective as an adjunctive to the non-surgical treatment of periodontitis.

Facial Aesthetic Laser-Assisted Protocol for the Management of Acne and Pigmentation: A Case Report

The demand for aesthetic procedures is significantly increasing worldwide. In this case report, an in-office laser-assisted protocol coupled with rejuvenating concentrate serum (Gluage, TEBISKIN Gluage, SkinMed, Italy) was made. A 24-year-old female patient presented with a chief complaint of abundant facial acne and localized pigmentation. Clinical examination revealed the presence of abundant acne on the forehead and cheeks and the presence of localized pigmentation. Laser-assisted protocol coupled with rejuvenating concentrate serum was suggested. The protocol consisted of a thorough cleansing of the face followed by irradiation with a 980 nm diode laser (Smart M, Lasotronix, Poland), followed by a 405 nm diode laser (Smart M, Lasotronix, Poland), the application of rejuvenating concentrate serum (Gluage, TEBISKIN Gluage, SkinMed, Italy), and irradiation with the 635 nm diode laser (Smart M, Lasotronix, Poland). The protocol was made once per week for three weeks (three sessions in total), and a three-month follow-up was made after the end of the last session to confirm the effectiveness of the treatment. Stomatology 1 diode laser (Smart M, Lasotronix, Poland) was used in this case report as a 980 nm, 405 nm, and 635 nm diode laser (Smart M, Lasotronix, Poland). During the follow-up period, an almost total reduction of the acne was observed with the total disappearance of the localized pigmentation. This case report confirms the effectiveness of the proposed laser-assisted facial aesthetic treatment. We invite further studies to be made within the same suggested promising protocol.

The Potential Role of a Surface-Modified Additive-Manufactured Healing Abutment on the Expression of Integrins α2, β1, αv, and β6 in the Peri-Implant Mucosa: A Preliminary Human Study

The stability of peri-implant soft tissues is essential for long-term success. Integrins play a vital role in biological processes through developing and maintaining cell interactions; however, few studies have evaluated the effects of modifications to abutment surfaces on cell adhesion across integrin expression. Therefore, this pilot study assessed the influence of different surface topographies of titanium healing abutments prepared by additive manufacturing (AM) on the gene expression levels of the integrin subunits α2, β1, αv, and β6 in the human peri-implant mucosa. Thirteen healthy adults were included. Depending on the number of required implants, the subjects were distributed in different groups as a function of healing abutment topography: group 1 (fully rough surface); group 2 (upper machined + lower rough); group 3 (rough upper surface + lower machined); group 4 (fully machined). A total of 40 samples (n = 10/group) of the peri-implant mucosa around the abutments were collected 30 days after implant placement, and subsequently, the gene expression levels were evaluated using real-time PCR. The levels of gene expression of β1-subunit integrin were upregulated for individuals receiving fully rough surface abutments compared with the other surface topographies (p < 0.05). However, the healing abutment topography did not affect the gene expression levels of the α2, αv, and β6 integrin subunits in the human peri-implant mucosa (p > 0.05). This preliminary study suggested that controlled modifications of the surface topography of titanium healing abutments produced by AM may influence the quality of the peri-implant mucosa in the early stages of the soft tissue healing process.

Transcription Factor AhR, Cytokines IL-6 and IL-22 in Subjects with and without Peri-Implantitis: A Case Control-Study

Peri-implantitis is a plaque-associated condition characterized by mucosal inflammation and subsequent progressive loss of supporting bone; it is caused by bacterial biofilm, but the host response triggered by bacterial stimulation promotes the release of cells and mediators that culminate in tissue destruction. The Aryl-hydrocarbon Receptor (AhR) is associated with IL-22 production by Th22 and Th17 CD4+ Th cells. The presence of IL-6 may promote the Th22 phenotype. The present case-control study evaluated the gene expression of AhR, IL-22, and IL-6 in the peri-implant tissues of healthy and peri-implantitis patients. Tissue biopsies were collected from thirty-five volunteers (15 healthy and 20 with peri-implantitis). A real-time PCR reaction was utilized to assess the AhR, IL-22, and IL-6 gene expression levels relative to the reference gene (GAPDH). The results were analyzed using the Mann-Whitney test with a significance level of 5%. Higher levels of gene expression of AhR and IL-6 were detected in peri-implantitis tissues. The IL-22 gene expression levels did not differ between groups. In conclusion, higher gene expression levels for AhR and IL-6 were detected in the soft tissues of peri-implantitis patients. IL-22 did not vary between conditions, which may indicate the loss of the immunomodulatory role of IL-22 in periimplantitis.

In Vitro Study of Laser-Assisted Prefabricated Ceramic Crown Debonding as Compared to Traditional Rotary Instrument Removal

This study compared the laser and rotary removals of prefabricated zirconia crowns in primary anterior and permanent posterior teeth. Sixty-two extracted teeth were prepared for prefabricated zirconia crowns cemented with resin-modified glass-ionomer cement. Specimens underwent crown removals by a rotary handpiece, or erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser. Pulpal temperatures, removal times, and scanning electron microscopy (SEM) examinations were compared. The average crown removal time for rotary and laser methods was 80.9 ± 19.36 s and 353.3 ± 110.6 s, respectively, for anterior primary teeth; and 114.2 ± 32.1 s and 288.5 ± 76.1 s, respectively, for posterior teeth (p < 0.001). The maximum temperature for the rotary and laser groups was 22.2 ± 8.5 °C and 27.7 ± 1.6 °C for anterior teeth, respectively (p < 0.001); and 21.8 ± 0.77 °C and 25.8 ± 0.85 °C for the posterior teeth, respectively (p < 0.001). More open dentinal tubules appeared in the rotary than the laser group. The rotary handpiece removal method may be more efficient than the laser with lower pulpal temperature changes. However, the laser method does not create noticeable tooth or crown structural damage compared to the rotary method.

Effects of Osseodensification on Immediate Implant Placement: Retrospective Analysis of 211 Implants

Osseodensification is a new method of bone instrumentation for dental implant placement that preserves bulk bone and increases primary implant stability, and may accelerate the implant rehabilitation treatment period and provide higher success and survival rates than conventional methods. The aim of this retrospective study was to evaluate and discuss results obtained on immediate implant placement with immediate and delayed loading protocols under Osseodensification bone instrumentation. This study included private practice patients that required dental implant rehabilitation, between February 2017 and October 2019. All implants were placed under Osseodensification and had to be in function for at least 12 months to be included on the study. A total of 211 implants were included in the study, with a 98.1% total survival rate (97.9% in the maxilla and 98.5% in the mandible). For immediate implants with immediate load, 99.2% survival rate was achieved, and 100% survival rate for immediate implant placement without immediate load cases. A total of four implants were lost during this period, and all of them were lost within two months after placement. Within the limitations of this study, it can be concluded that Osseodensification bone instrumentation provided similar or better results on survival rates than conventional bone instrumentation.

Efficacy of Various Laser Wavelengths in the Surgical Treatment of Ankyloglossia: A Systematic Review

Ankyloglossia, commonly known as tongue-tie, is the most common disorder of tongue morphology characterized by aberrant attachment of the lingual frenum. This study aimed to provide a comprehensive literature review and evaluate the effectiveness of various laser wavelengths in the surgical treatment of patients with ankyloglossia. An electronic screening of PubMed and the Cochrane Central Register of Controlled Trials (CENTRAL) databases was conducted on 8 November 2021. The following search terms were used to review the available data on the subject of interest: (ankyloglossia OR tongue tie OR short lingual frenulum OR lingual frenectomy OR lingual frenulectomy OR lingual frenotomy OR lingual frenulotomy) AND laser. The use of lasers in ankyloglossia treatment resulted in shorter procedure time, reduced indications for general anesthesia, reduced administration of postoperative analgesics, fewer sutures or none needed, reduced postoperative bleeding, and improved healing. Despite many advantages, this method has its clinical limitations: it requires the use of expensive equipment; well-trained personnel familiar with lasers; and personal protective equipment for the patient, caregiver, operator, and assistant. The laser procedure does not eliminate the need for myofunctional exercises and work with a speech therapist.

Disinfection Potential of 980 nm Diode Laser and Hydrogen Peroxide (3%) in "Critical Probing Depths" Periodontal Pockets: Retrospective Study

A successful treatment of periodontitis depends largely on the successful elimination of the periodontopathogens during non-surgical and surgical mechanical debridement. In this retrospective study, data collection was conducted from 2017 to 2021. The retrospective study included 128 patients with 128 sites of localized periodontitis with pocket depths > 5 mm. The included data were based on sites that received conventional mechanical debridement followed by different adjunctive approaches. In total, 30 patients did not receive any additional treatment (SRP group), 30 patients received SRP + 980 nm diode laser irradiation only (SRP + laser), 30 patients received SRP + 3% hydrogen peroxide irrigation (SRP + H2O2) only and 30 patients received a combined treatment of 3% hydrogen peroxide and 980 nm diode laser irradiation (SRP + H2O2 + laser). Total bacterial counts (TBC) in the periodontal pocket collected for all participants before treatment, immediately after treatment, 6 weeks after treatment, 12 weeks after treatment and 6 months after treatment were statistically analyzed and compared. When the laser was used, irradiation parameters were 10 μsec/pulse duration, 10 kHz, pick power of 10 W, average power of 1 W, irradiation time of one minute with inward and outward movements, and fiber diameter of 320 μm. The irradiation was repeated 3 times/pocket. When hydrogen peroxide was used, the irrigation was conducted for one minute and repeated 3 times. The maximum reduction in TBC was obtained when SRP was coupled with 3% H2O2 irrigation followed by 980 nm diode laser irradiation. After six months of follow-up, a significant reduction in TBC was obtained for the group of SRP + H2O2 + laser when compared to all the other groups, from 7.27 × 107 before intervention to 3.21 × 107 after six months. All three approaches to SRP showed a significant reduction in TBC immediately after treatment. Values were 3.52 × 107, 4.01 × 106, 9.58 × 106, 1.98 × 106 for SRP alone, SRP + diode, SRP + H2O2 and SRP + H2O2 + diode laser, respectively. At 6 months, we saw no significant difference between SRP + laser and SRP + H2O2 with 4.01 × 107 and 4.32 × 107, respectively. This retrospective study reveals that after SRP, irrigation with 3% hydrogen peroxide and irradiation with a 980 nm diode laser within specific treatment protocol can be used as an additional approach to conventional SRP to increase the disinfection of the periodontal pockets > 5 mm.

Fibroblasts Adhesion to Laser-Modified Titanium Surfaces-A Systematic Review

OBJECTIVE

Laser treatment has been recently introduced in many fields of implant dentistry. The systematic review tried to address the question: "How does laser modification of titanium surface influence fibroblast adhesion?".

METHODS

An electronic search of the PubMed and Scopus databases was performed. The following keywords were used: (laser) AND (fibroblast) AND (titanium) AND (implant OR disc) AND (proliferation OR adhesion). Initially, 136 studies were found. Ten studies met the inclusion criteria and were included in the review. All studies chosen to be included in the review were considered to have a low risk of bias.

RESULTS

Studies included in the review varied with laser parameters or ways of observing fibroblast behavior. Studies showed that fibroblasts tend to take different shapes and create extensions on modified surfaces and that their metabolic activity is more intense. One study concentrated on laser application and showed that three-directional laser application is the most successful in terms of fibroblast adhesion. Studies which concentrated more on laser parameters showed that too low energy density (lower or equal to 0.75 J/cm2) does not influence fibroblast adhesion. Increasing the energy density over 0.75 J/cm2 causes better cell adhesion of fibroblasts to the laser-modified sample. One included study focused on increasing titanium surface wettability, which also positively influenced cell adhesion.

CONCLUSION

The studies included in the review proved a positive effect of laser-modified titanium surfaces on fibroblast adhesion. However, the application of an appropriate laser energy dose is crucial.

SEM Evaluation of Tooth Surface after a Composite Filling Removal Using Er:YAG Laser, Drills with and without Curettes, and Optional EDTA or NaOCl Conditioning

(1) Background: This study aimed to evaluate the microporosity of the tooth surface structure adjacent to the cemento-enamel junction (CEJ) after the removal of composite fillings with a drill in comparison with removal by an Er:YAG laser and after cleaning with a periodontal curette, chemical EDTA and NaOCl (sodium hypochlorite) conditioning. (2) Methods: The research material consisted of 30 extracted premolars with cervical composite fillings. The teeth were divided into six groups according to the method of tooth preparation: group G1 (n = 5)-a diamond drill; group G2 (n = 5)-a diamond drill + curette; group G3 (n = 5)-a diamond drill + 24% EDTA (PrefGel, Straumann, Switzerland); group G4 (n = 5)-an Er:YAG laser (LightWalker, Fotona, Ljubljana, Slovenia) set with the following parameters: power: 1.65 W (composite removal, CR), 1.2 (tooth conditioning, TC), energy: 110 mJ (CR), 80 mJ (TC), frequency: 15 Hz, pulse duration: 50 μs, tip diameter: 1 mm, air/fluid cooling: 4, distance 1.5 mm, energy density: 14.01 J/cm2 (CR), 10.19 J/cm2 (TC); group G5 (n = 5)-an Er:YAG laser + 2% sodium hypochlorite (NaOCl); group G6 (n = 5)-an Er:YAG laser + 5.25% NaOCl. In each tooth, three cavities were made and subjected to analysis. The dentin surface was evaluated using a scanning electron microscope (SEM). (3) Results: Groups G1 and G2 exhibited mechanical damage to the tooth surface structure caused by the rotary motion of a diamond drill. The SEM image showed a smear layer that could only be removed chemically using 24% EDTA gel (group G3). The tooth surfaces prepared with the Er:YAG laser (groups G4-G6) revealed a homogeneous structure without damage along with open dentinal tubules (without smear layer) and visible denaturation of collagen fibers. The sodium hypochlorite (NaOCl) conditioning did not increase the visibility of dentinal tubules. (4) Conclusions: Dentin surfaces have open dentinal tubules after removal of the composite filling using the Er:YAG laser and therefore do not require additional NaOCl conditioning.

Photobiomodulation with Red and Near-Infrared Light Improves Viability and Modulates Expression of Mesenchymal and Apoptotic-Related Markers in Human Gingival Fibroblasts

Photobiomodulation (PBM), also called low-level laser treatment (LLLT), has been considered a promising tool in periodontal treatment due to its anti-inflammatory and wound healing properties. However, photobiomodulation's effectiveness depends on a combination of parameters, such as energy density, the duration and frequency of the irradiation sessions, and wavelength, which has been shown to play a key role in laser-tissue interaction. The objective of the study was to compare the in vitro effects of two different wavelengths-635 nm and 808 nm-on the human primary gingival fibroblasts in terms of viability, oxidative stress, inflammation markers, and specific gene expression during the four treatment sessions at power and energy density widely used in dental practice (100 mW, 4 J/cm²). PBM with both 635 and 808 nm at 4 J/cm² increased the cell number, modulated extracellular oxidative stress and inflammation markers and decreased the susceptibility of human primary gingival fibroblasts to apoptosis through the downregulation of apoptotic-related genes (P53, CASP9, BAX). Moreover, modulation of mesenchymal markers expression (CD90, CD105) can reflect the possible changes in the differentiation status of irradiated fibroblasts. The most pronounced results were observed following the third irradiation session. They should be considered for the possible optimization of existing low-level laser irradiation protocols used in periodontal therapies.

Monitoring of Changes in Masticatory Muscle Stiffness after Gum Chewing Using Shear Wave Elastography

This study aimed to investigate if intensive exercise affects the stiffness of the masticatory muscles measured with shear-wave elastography. The study included a cohort of healthy adults (n = 40) aged 40 ± 11 years. In each individual, the stiffness of both the masseter and temporalis muscle was examined three times: at baseline, after 10 min of intensive exercise (chewing gum), and after 10 min of relaxation. Stiffness values (median (IQR)) of both the masseter and temporalis muscle were the lowest at the baseline (11.35 (9.7–12.65) and 10.1 (9.1–10.95)), increased significantly after the exercise (12.5 (11.1–13.25) and 10.3 (10.2–10.52)) and then dropped significantly after 10 min of relaxing (11.75 (9.95–12.6) and 10.2 (9.65–11.9)). The stiffness of the temporalis muscle was significantly lower than that of the masseter muscle. The values of the stiffness of the masseters correlated significantly with the values of the stiffness of the temporalis muscles. Shear wave elastography proved to be a sensitive method for showing changes in the stiffness of the muscles involved in the mastication occurring as a response to the effort, which increased the muscle stiffness. Further research is needed to broaden knowledge on the impact of eating habits and the occurrence of parafunctions on the development of temporomandibular disorders and the condition of masticatory muscles.

Efficacy of Toluidine Blue-Mediated Antimicrobial Photodynamic Therapy on Candida spp. A Systematic Review

The effectiveness of antimicrobial photodynamic therapy (aPDT) in the treatment of oral yeast infections was examined many times in recent years. The authors of this review tried to address the question: "Should TBO (toluidine blue ortho)-mediated aPDT be considered a possible alternative treatment for oral candidiasis?". PubMed/Medline and the Cochrane Central Register of Controlled Trials (CEN-TRAL) databases were searched from 1997 up to the 27th of October 2020 using a combination of the following keywords: (Candida OR Candidiasis oral OR Candidosis oral OR denture stomatitis) AND (toluidine blue OR photodynamic therapy OR aPDT OR photodynamic antimicrobial chemotherapy OR PACT OR photodynamic inactivation OR PDI). Animal studies or in vitro studies involving Candida albicans (C. albicans) and/or nonalbicans stain, randomized clinical trials (RCT) involving patients with oral candidiasis or denture stomatitis published solely in English language were included. Candida elimination method in animal, in vitro studies and RCT used was TBO-mediated aPDT. Exactly 393 studies were taken into consideration. Then, after analyzing titles and abstracts of said studies, 361 were excluded. Only 32 studies ended up being selected for in-depth screening, after which 21 of them were included in this study. All studies reported the antifungal effectiveness of aPDT with TBO against C. albicans and non-albicans Candida. In studies conducted with planktonic cells, only one study showed eradication of C. albicans. All others showed partial elimination and only one of them was not statistically significant. Experiments on yeast biofilms, in all cases, showed partial, statistically significant cell growth inhibition and weight reduction (a reduction in the number of cells-mainly hyphae) and the mass of extracellular polymeric substance (EPS). In vivo aPDT mediated by TBO exhibits antifungal effects against oral Candida spp.; however, its clinical effectiveness as a potent therapeutic strategy for oral yeast infections requires further investigation.

Schemes for Drug-Induced Treatment of Osteonecrosis of Jaws with Particular Emphasis on the Influence of Vitamin D on Therapeutic Effects

Drugs that inhibit bone resorption are prescribed most often by orthopedists, hematologists, or oncologists. Dental practice rarely draws attention to their importance and the effects they carry. The problem concerns mainly older people owing to oncological problems or postmenopausal consequences, but everyone can be at risk. Carefully conducted interviews and analysis of history and disease should always be performed before any action is taken by patients taking this type of medicine. Further action should consider possible complications and, above all, the risk of their occurrence. In this article, the most important issues related to the treatment of drug-induced osteonecrosis of the jaws (ONJ) are raised, including medication-related osteonecrosis of the jaw (MRONJ); conservative treatment, including the use of laser; and the impact of vitamin D supplementation on the overall treatment, prognosis, and prevention before complication, which is osteonecrosis of the jaw in the course of treatment with bisphosphonates and other drugs predisposing to MRONJ, such as denosumab and angiogenesis inhibitors. The degree of osteonecrosis is also critical, as it is possible to avoid surgical procedures for only conservative methods that sometimes bring good results. Surgical treatment of advanced stages is complicated and carries a high risk of error and complications. MRONJ is a disease that is easy to avoid, but it is difficult to treat and treatment sometimes leads only to a partial remission of the disease, not a complete cure.

Assessment of Human Gingival Fibroblast Proliferation after Laser Stimulation In Vitro Using Different Laser Types and Wavelengths (1064, 980, 635, 450, and 405 nm)-Preliminary Report

Purpose: to assess the effect of photobiomodulation (PBM) on human gingival fibroblast proliferation. Methods: The study was conducted using the primary cell cultures of human fibroblasts collected from systemically healthy donors. Three different laser types, Nd:YAG (1064 nm), infrared diode laser (980 nm), and prototype led laser emitting 405, 450, and 635 nm were used to irradiate the fibroblasts. Due to the patented structure of that laser, it was possible to irradiate fibroblasts with a beam combining two or three wavelengths. The energy density was 3 J/cm², 25 J/cm², 64 J/cm². The viability and proliferation of cells were determined using the (Thiazolyl Blue Tetrazolium Blue) (MTT) test conducted 24, 48, and 72 h after laser irradiation. Results: The highest percentage of mitochondrial activity (MA = 122.1%) was observed in the group irradiated with the 635 nm laser, with an energy density of 64 J/cm² after 48 h. The lowest percentage of MA (94.0%) was observed in the group simultaneously irradiated with three wavelengths (405 + 450 + 635 nm). The use of the 405 nm laser at 25 J/cm² gave similar results to the 635 nm laser. Conclusions: The application of the 635 nm and 405 nm irradiation caused a statistically significant increase in the proliferation of gingival fibroblasts.

Laser dentistry in daily practice during the COVID-19 pandemic: Benefits, risks and recommendations for safe treatments

The COVID-19 pandemic forced dental professionals to cope with an unexpected challenge and caused an abrupt cessation of conventional care practices. The high degree of contagiousness as well as the diffusion of the virus through the air and droplets via respiratory transmission placed dental professionals at top-level risk of contracting and spreading the disease. General recommendations were announced in different countries, including patient distancing, air ventilation, surface and instrument sanitization, and the wearing of suitable masks and shields. However, many dental treatments are performed using lasers, and some specific precautions must be added to conventional procedures to ensure the advantages of this technology to patients because of the particular tissue–matter interaction effects of laser wavelengths. Based on the literature, the authors evaluated all of using laser wavelengths to analyze the risk and the benefits of using lasers in daily dental practice, and to provide safety recommendations during pandemic. An unrestricted search of indexed databases was performed. Laser use effects were categorized into: 1) explosive processes that produce tissue ablation and aerosol formation; 2) thermal actions that create vaporization and smoke plume; 3) photobiomodulation of the cells; and 4) enhanced chemical activity. Knowledge of the device functions and choice of adequate parameters will reduce aerosol and plume formation, and the application of suction systems with high flow volume and good filtration close to the surgical site will avoid virus dissemination during laser use. In the categories that involve low energy, the beneficial effects of lasers are available and sometimes preferable during this pandemic because only conventional precautions are required. Lasers maintain the potential to add benefits to dental practice even in the COVID-19 era, but it is necessary to know how lasers work to utilize these advantages. The great potential of laser light, with undiscovered limits, may provide a different path to face the severe health challenges of this pandemic.

Evaluation of Er:YAG and Er,Cr:YSGG laser irradiation for the debonding of prefabricated zirconia crowns

BACKGROUND

Reduced tooth structure in the pediatric and adolescent population is frequently restored with prefabricated zirconia crowns. On permanent teeth, these restorations may need to be removed and replaced with permanent restorations.

OBJECTIVES

To explore and compare the use of 2 high-powered erbium lasers for removing prefabricated zirconia crowns from molar teeth as a non-invasive alternative to rotary instruments.

MATERIAL AND METHODS

Twenty-five permanent molars were prepared to dentin and prefabricated all-ceramic zirconia crowns were fitted and cemented with resin modified glass ionomer (RMGI) cement. The teeth were randomly assigned into one of the 2 retrieval treatment groups: the erbium-doped yttrium, aluminum and garnet (Er:YAG) laser group (G1; n = 12) or the erbium, chromium-doped yttrium, scandium, gallium and garnet laser (Er,Cr:YSGG) laser group (G2; n = 13). The laser operating parameters for the Er:YAG laser were 300 mJ, 15 Hz, 4.5 W, and 50-microsecond pulse duration (SSP mode); for the Er,Cr:YSGG laser, they were 4.5 W, 15 Hz, 20 water/20 air, and 5 W, 15 Hz, 50 water/50 air, and 60-microsecond pulse duration (H mode). The experiment was repeated twice. The surface area and the volume of teeth and crowns were measured and the cement space was calculated. The retrieval time and temperature changes were tested and recorded. The data were analyzed with the t-test. The surfaces of the dentin and the crown from each group were further examined using scanning electron microscopy (SEM).

RESULTS

The average time for crown removal using the Er:YAG laser was 1 min 32.7 s; for the Er,Cr:YSGG laser it was 3 min 13.9 s (p < 0.0001). The mean temperature changes were 1.41 ±1.36°C for the Er:YAG laser and 2.2 ±0.99°C for the Er,Cr:YSGG laser (p = 0.0321). The SEM examination showed no damage or major structural changes caused by treatment with either erbium-family laser.

CONCLUSIONS

Both lasers are effective, non-invasive tools to remove prefabricated zirconia crowns cemented with resin cement and should be considered as viable alternatives to rotary instrumentation.

Retrieval of Prefabricated Zirconia Crowns with Er,Cr:YSGG Laser from Primary and Permanent Molars

(1) Background: Prefabricated zirconia crowns are used to restore teeth in children. The purpose of this study was to evaluate the removal of these crowns with the erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser; (2) Methods: A total of 12 primary and 12 permanent teeth were prepared and prefabricated zirconia crowns were passively fitted and cemented with two resin modified glass-ionomer (RMGI) cements. Surface areas of prepared teeth and crowns were calculated. Crowns were removed using two laser settings: 4.5 Watts, 15 Hertz, 20 water/20 air, and 5 Watts, 15 Hertz, 50 water/50 air. The retrieval time and temperature changes were tested recorded. Data were analyzed using ANOVA with Tukey’s adjusted post hoc pairwise comparison t-test; (3) Results: The average time for crown removal was: 3 min, 47.7 s for permanent; and 2 min 5 s for primary teeth. The mean temperature changes were 2.48 °C (SD = 1.43) for permanent; and 3.14 °C (SD = 1.88) for primary teeth. The time to debond was significantly positively correlated with tooth inner surface area and volume, outer crown volume, and the cement volume; (4) Conclusions: Use of the Er,Cr:YSGG laser is an effective, safe and non-invasive method to remove prefabricated zirconia crowns cemented with RMGI cements from permanent and primary teeth.

Dental Aerosol as a Hazard Risk for Dental Workers

Standard dental procedures, when using a water coolant and rotary instruments, generate aerosols with a significantly higher number of various dangerous pathogens (viruses, bacteria, and fungi). Reducing the amount of aerosols to a minimum is mandatory, especially during the new coronavirus disease, COVID-19. The study aimed to evaluate the amount of aerosol generated during standard dental procedures such as caries removal (using dental bur on a high and low-speed handpiece and Er:YAG laser), ultrasonic scaling, and tooth polishing (using silicon rubber on low-speed handpiece) combined with various suction systems. The airborne aerosols containing particles in a range of 0.3-10.0 μm were measured using the PC200 laser particle counter (Trotec GmbH, Schwerin, Germany) at three following sites, manikin, operator, and assistant mouth, respectively. The following suction systems were used to remove aerosols: saliva ejector, high volume evacuator, saliva ejector with extraoral vacuum, high volume evacuator with extraoral vacuum, Zirc® evacuator (Mr.Thirsty One-Step®), and two customized high volume evacuators (white and black). The study results showed that caries removal with a high-speed handpiece and saliva ejector generates the highest amount of spray particles at each measured site. The aerosol measurement at the manikin mouth showed the highest particle amount during caries removal with the low and high-speed handpiece. The results for the new high volume evacuator (black) and the Zirc® evacuator showed the lowest increase in aerosol level during caries removal with a high-speed handpiece. The Er:YAG laser used for caries removal produced the lowest aerosol amount at the manikin mouth level compared to conventional dental handpieces. Furthermore, ultrasonic scaling caused a minimal aerosol rise in terms of the caries removal with bur. The Er:YAG laser and the new wider high volume evacuators improved significantly suction efficiency during dental treatment. The use of new suction systems and the Er:YAG laser allows for the improvement of biological safety in the dental office, which is especially crucial during the COVID-19 pandemic.

Treatment with Nd:YAG Laser Irradiation Combined with Sodium Hypochlorite or Hydrogen Peroxide Irrigation on Periodontal Pathogens: An In Vitro Study

Objective: The purpose of this study was to evaluate the effect of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser with low concentrations of hydrogen peroxide (H₂O₂) or sodium hypochlorite (NaOCl) on viability of oral bacteria. Materials and methods: Bacterial species Streptococcus gordonii, Porphyromonas gingivalis, and Fusobacterium nucleatum were grown in an anaerobic chamber at 37°C. Samples were irradiated with the Nd:YAG laser (1064 nm, 300 μm Varian tip) using parameters: 150 mJ, 20 Hz, 3 W, 50 sec, and 100 μs short pulse duration in contact mode. Treatment groups included (1) control, (2) Nd:YAG, (3) 0.5% H₂O₂, (4) Nd:YAG and 0.5% H₂O₂, (5) 0.5% NaOCl, and (6) Nd:YAG with 0.5% NaOCl. Viable colonies were counted, calculated into colony forming unit/mL, and converted into log form for statistical analysis using a two-tailed paired t-test. Results: The combined treatment with the Nd:YAG and H₂O₂ showed the greatest reduction in all bacterial viability compared with other treatment groups (p < 0.001). Antiseptic solutions and laser were most effective against P. gingivalis, least effective against S. gordonii but improved significantly in combination with laser irradiation (p < 0.001). Laser alone was effective against all of three bacterial species, however, it was not significant. Conclusions: Combination treatment with Nd:YAG laser and an oxidative disinfectant (0.5% NaOCl or H₂O₂) resulted in more effective reduction of bacterial viability than monotherapies.

A Clinical Trial of Photobiomodulation Effect on Orthodontic Microscrews Stability Using a 635 nm Red Laser Light

Background: One of the procedures enhancing implants stability can be photobiomodulation. Objective: To assess the effect of a 635 nm wavelength on orthodontic microscrews stability, survival rate, and an individual patient's pain score. Materials and methods: The study was done with 15 subjects, 30 orthodontic microscrews with a length of 10 mm and diameter 1.4 mm. Implants inserted on the right and left side of the maxilla. The implants in the test group (G1) were irradiated with the laser at palatal and buccal part of peri-implant area (two points). The diode laser (SmartM PRO; Lasotronix, Warsaw, Poland) was used with the following settings: power: 100 mW, spot size: 0.5 cm², mean power density (irradiance): 200 mW/cm², in continuous wave (CW) mode, energy per point: 4 J, radiant exposure: 8 J/cm², time per point: 40 sec, the total energy dose (radiant energy) per session: 8 J in contact mode, handpiece diameter: 8 mm. Laser sessions: day of surgery and 3, 6, 9, 12, 15, 30 days later. Cumulative radiant energy was 59 J. Periotest appliance was used to assess the microscrews stability at day of surgery and 3, 6, 9, 12, 15, 30, 60 days later. Each patient received a survey for individual pain assessment (NRS-11) promptly after the implantation. Results: The analysis after 60 days revealed significantly higher secondary stability for the laser-irradiated microscrews group in comparison with control implants (G2 group) (p = 0.0037). We observed significantly higher stability in the experimental group compared with the control after 30 days (p = 0.0218). Moreover, we noted significantly higher microimplants stability for the control group in comparison with the test group, 9 days after implantation (p = 0.0374). Laser application had no effect on pain reduction noted in the first day in comparison with the control sites (p = 0.6690). No microscrews were lost in the study. Conclusions: Application of a 635 nm laser on peri-implant soft tissue increased the microscrews stability after 30 and 60 days.

Clinical Evaluation of Diode (980 nm) Laser-Assisted Nonsurgical Periodontal Pocket Therapy: A Randomized Comparative Clinical Trial and Bacteriological Study

Background: Mechanical debridement is the gold standard in the periodontitis therapy. However, it is suggested that adjunctive use of lasers can result in a more effective treatment outcome. Objective: Evaluate the efficiency of diode laser-assisted nonsurgical therapy of periodontitis as adjunctive to scaling and root planing (SRP). Methods: One hundred sixty vertical bone defects [pocket depth (PD) at baseline ≥6 mm] had been randomly allocated to receive SRP alone (group C) or SRP coupled to a diode laser (980 nm) protocol (group C+L): SRP, irrigation with hydrogen peroxide solution (3%), de-epithelization of the internal and external gingiva followed by blood stabilization, and coagulation by laser beam were made. Beam parameters: 10 μsec/pulse duration, 10 kHz, pick power of 10 W, average power of 1 W, and fiber diameter of 400 μm. Plaque index (PI), bleeding on probing, gingival recession (GR), clinical attachment level (CAL), and PD were measured at baseline, at 6 weeks, 12 weeks, 18 weeks, 6 months, and 12 months. Microbiological data were collected randomly from 26 pockets from both groups at baseline, 6 weeks, 12 weeks, and 6 months after treatment. Results: At all periods of follow-up, there was a significant difference between both groups in all clinical parameters except in GR. In group C+L, 76% of pockets had PD ≤3 mm after 12 months of follow-up and an average of PD = 1.77 ± 0.46 mm, while 56% of pockets in group control (C) had an average of PD = 5.00 ± 0.83 mm after 12 months of follow-up. Total bacteria count in group C + L was significantly lower compared to group C only at 12 weeks and 6 months of follow-up. Furthermore, there was high significant decrease in the number of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, and Prevotella intermedia at all the follow-up periods. Conclusions: As adjunctive to SRP, diode laser-assisted nonsurgical therapy of periodontitis has significantly improved clinical parameters of PI and POB and has significantly reduced the clinical attachment loss (CAL) and PD compared to the control group after 1 year of follow-up. A significant reduction in periodontal pathogens has been observed in group C + L only at 12 weeks and 6 months of follow-up.

Exploring the use of pulsed erbium lasers to retrieve a zirconia crown from a zirconia implant abutment

Background

Removal of cement-retained implant fixed restorations when needed, can be challenging. Conventional methods of crown removal are time consuming and costly for patients and practitioners. This research explored the use of two different types of pulsed erbium lasers as a non-invasive tool to retrieve cemented zirconia crowns from zirconia implant abutments.

Materials and methods

Twenty identical zirconia crowns were cemented onto 20 identical zirconia prefabricated abutments using self-adhesive resin cement. The specimens were divided into two groups for laser assisted crown removal; G1 for erbium-doped yttrium aluminum garnet laser (Er:YAG), and G2 for erbium, chromium-doped yttrium, scandium, gallium and garnet (Er,Cr:YSGG). For the G1, after the first crown removal, the specimens were re-cemented and removed again using the Er:YAG laser. Times needed to remove the crowns were recorded and analyzed using ANOVA (α = 0.05). The surfaces of the crown and the abutment were further examined using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analyses.

Results

The average times of zirconia crown removal from zirconia abutments were 5 min 20 sec and 5 min 15 sec for the Er:YAG laser of first and second experiments (G1), and 5 min 55 sec for the Er,Cr:YSGG laser experiment (G2). No statistical differences were observed among the groups. SEM and EDS examinations of the materials showed no visual surface damaging or material alteration from the two pulsed erbium lasers.

Conclusions

Both types of pulsed erbium lasers can be viable alternatives for retrieving a zirconia crown from a zirconia implant abutment. Despite operating at different wavelengths, the Er:YAG and Er,Cr:YSGG lasers, perform similarly in removing a zirconia crown from a zirconia implant abutment with similar parameters. There are no visual and elemental composition damages as a result of irradiation with pulsed erbium lasers.

Effect of 808 nm Semiconductor Laser on the Stability of Orthodontic Micro-Implants: A Split-Mouth Study

BACKGROUND

To evaluate the effect of photobiomodulation (PBM) on orthodontic micro-implants (n = 44; 14 women, 8 men).

METHODS

PBM with 808 nm diode laser was applied immediately, 3, 6, 9, 12, 15, and 30 days post the implantation. Results were assessed within same time frames and additionally after 60 days to check for implants stability using the Periotest device. Patients pain experiences following the first day post-treatment and potential loss of micro-implants after 60 days were recorded. The procedure involved insertion of mini-implants in the maxilla for the laser group (L, n = 22) and negative control group (C, n = 22). Irradiation was carried buccally and palatally with respect to the maxillary ridge (2 points). The energy per point was 4 J (8 J/cm2), total dose was 56 J.

RESULTS

Patients did not report significant differences in terms of pain experiences comparing the L and C groups (p = 0.499). At 30 days post-treatment, higher secondary stability of implants was observed in the laser group (Periotest Test Value, PTV 6.32 ± 3.62), in contrast to the controls (PTV 11.34 ± 5.76) (p = 0.004). At 60 days post-treatment, significantly higher stability was recorded in the laser group (PTV 6.55 ± 4.66) compared with the controls, PTV (10.95 ± 4.77) (p = 0.009). Conclusions: Application of the 808 nm diode laser increased secondary micro-implant stability.

Temperature Changes and SEM Effects of Three Different Implants-Abutment Connection during Debridement with Er:YAG Laser: An Ex Vivo Study

The study aimed to evaluate a temperature increase in, and damage to, titanium implants during flapless laser debridement. The study analyzed 15 implants with various implant–abutment connections: a two-piece implant (n = 4) with a screw abutment (IA—Implant–Abutment) and a one-piece implant with a ball type fixture (BTF, n = 4) or fix type fixture (FTF, n = 4). The implants were placed in porcine mandibles 2 mm over a bone crest to imitate a peri-implantitis. The implants were debrided in contact mode for 60 s with a Er:YAG laser at fluence of 9.95 J/cm² (G1 group: 50 mJ/30 Hz); 19.89 J/cm² (G2 group: 100 mJ/30 Hz); 39.79 J/cm² (G3 group: 200 mJ/30 Hz), or a scaler with a ceramic tip (G4 control group: 4 W/20 Hz). The temperature was measured with thermocouples at implant and abutment levels. The damage in the titanium surface (n = 3, non-irradiated implants from each type) was assessed using SEM (Scanning Electron Microscopy). The temperature increase at the implant level for the laser was higher at IA in contrast with FTF and BTF. (p < 0.05) The temperature change at the abutment level was lower for the scaler in contrast to Er:YAG laser at FTF. (p < 0.0002) Er:YAG laser didn’t increase the temperature by 10 °C at 100 mJ/30 Hz and 50 mJ/30 Hz. Based on SEM analysis, cracks occurred on the surface of two-piece implants and were more pronounced. Cracks and the melting of the titanium surface of two-piece implants cleaned with Er:YAG laser at 100 or 200 mJ were observed. The specimens treated with the ultrasonic scaler with a plastic curette showed the remaining dark debris on the titanium surface. We recommend using Er:YAG laser at 50 mJ/30 Hz during flapless implants debridement.

Retrieval of Glass Fiber Post Using Er:YAG Laser and Conventional Endodontic Ultrasonic Method: An In Vitro Study

PURPOSE

To compare the times and temperatures used to remove a glass fiber post from an endodontically treated tooth using erbium-doped yttrium aluminum garnet (Er:YAG) compared to conventional endodontic ultrasonic method.

MATERIALS AND METHODS

Thirty-four single-root human extracted teeth were endodontically treated ex vivo. The post space was prepared to 7 mm in depth and a 11.4 mm glass fiber post was cemented using composite resin cement. Specimens were kept in 100% humidity for 24 hours and then randomly assigned to Er:YAG laser or ultrasonic methods for post removal. The removal time was recorded. Specimens with a fractured post during the removal process were excluded. The temperature on the external surface of the root was measured at the coronal, middle, and apical third portions during the laser or ultrasonic applications from 1 to 10 minutes. Data were analyzed using one-tailed t-test and paired t-test (ɑ = 0.01) for the post removal time and temperature difference, respectively. The specimen surfaces were examined using scanning electron microscopy (SEM).

RESULTS

Fifteen specimens were tested in each group. Four specimens were fractured, 2 in the laser and 1 in ultrasonic group. One post was excluded because of laser tip damage. The average removal time were 98 ± 46.1 seconds for Er:YAG laser and 538 ± 215.6 seconds or ultrasonic groups with significant difference between the groups (p < 0.001). The temperature (°C) ranges measured from 1 to 10 minutes were [24.2°, 27.3°] for laser and [33.0°, 38.0°] for ultrasonic in the cervical area, [22.1°,24.6°] for laser and [31.0°, 34.6°] for ultrasonic in the middle area, and [24.4°, 27.7°] for laser and [30.3°, 34.1°] for ultrasonic in the apical area. There were significant differences between temperatures for each treatment (p < 0.001). SEM examination showed no visible damage caused by treatment with Er:YAG laser.

CONCLUSIONS

Er:YAG laser can remove posts up to 5 times faster than ultrasonic removal method. The laser causes lower temperature increase at the root surface compared to the ultrasonic removal. Er:YAG may be considered as a viable alternative to sonication for post removal.

In Vitro Examination of the Use of Er:YAG Laser to Retrieve Lithium Disilicate Crowns from Titanium Implant Abutments

PURPOSE

Removal of cement-retained implant crowns can be difficult and often requires sectioning of the prosthesis by rotary instruments. This study aimed to measure how much time is required in crown removal and the temperature changes when erbium-doped yttrium aluminum garnet (Er:YAG) laser was used to retrieve lithium disilicate crowns from titanium implant abutments luted with composite resin (CR) cement and resin-modified glass ionomer (RMGI).

MATERIALS AND METHODS

Forty identical lithium disilicate crowns were fabricated for prefabricated titanium abutments. CR and RMGI cements were used to lute the crowns, 20 specimens for each cement. Specimens were kept in 100% humidity for 48 hours. Er:YAG laser was then used to facilitate the crown retrieval. The retrieval time was recorded. The temperature changes at the abutment level for each type of cement were recorded during irradiation of 10 specimens for each type of cement from 1 to 10 minutes. Data were analyzed using t-test (ɑ = 0.01) and paired t-test (ɑ = 0.05). The surfaces of the crown and the abutment were further examined using scanning electron microscopy (SEM).

RESULTS

The average times of crown removal from titanium abutments were 196.5 seconds for CR and 97.5 seconds for RMGI groups with statistical significance (p < 0.001). The temperatures measured from 1 to 10 minutes of irradiation ranged from 18° to 20.8° for CR and 18° to 23° for RMGI at the abutment surface, and 22.1° to 24.6° for CR and 22° to 24.8° for RMGI at the crown surface. No statistical differences were observed between temperature changes at the abutment or the crown for each cement (p = 0.63); however, there was a statistically significant difference between the temperatures at the abutment and crown for both cements (p < 0.001). SEM examination showed no visible damage caused by treatment with Er:YAG laser.

CONCLUSIONS

It is faster to remove lithium disilicate crowns from titanium implant abutments when luted with RMGI compared to CR cement. The temperature rise was higher in the crown compared to the abutment. The type of cement had no effects on temperature changes. Heat generated from Er:YAG irradiation does not appear to be high enough to have any adverse effect on implant osseointegration.

Clinical and microbiological effects of multiple applications of antibacterial photodynamic therapy in periodontal maintenance patients. A randomized controlled clinical study

BACKGROUND

At present, very limited data are available on the clinical and microbiological outcomes obtained following repeated application of aPDT following one single mechanical debridement.

OBJECTIVE

To evaluate clinically and microbiologically the outcomes following one single session of subgingival mechanical debridement (scaling and root planing; e.g. SRP) followed by 1x immediate application of aPDT and 2 x subsequent use of aPDT without SRP.

MATERIALS AND METHODS

Forty patients diagnosed with generalized chronic periodontitis that were enrolled in periodontal maintenance (supportive periodontal therapy) program, were randomly assigned to one of the two treatments: 1. SRP by means of ultrasonic and hand instruments followed by one single session of SRP followed by 1x immediate application of aPDT and 2 x subsequent applications of aPDT without SRP (test) or 2. SRP alone (control). The following clinical parameters were recorded at baseline, at 3 and 6 months: Full-Mouth Plaque Scores (FMPS), Full-Mouth Bleeding Scores (BOP), Probing Pocket Depth (PPD), Clinical Attachment Level (CAL) and Gingival Recession (RC). Additionally, microbiological samples were evaluated at baseline and six months after treatment. The primary outcome variable was BOP.

RESULTS

Both treatments improved statistically significantly (p < 0.05) the FMPS, PPD and CAL values, while no statistically significant changes occurred in terms of RC. In the test group, BOP decreased statistically significantly (p < 0.05) after 3 and 6 months, while in the control group the respective values decreased statistically significantly only at 3 months. Both treatments reduced statistically significantly the total bacteria counts (TBC) after 6 months (p < 0.05). At 6 months, the use of SRP and aPDT resulted in a statistically significant decrease in the number of all tested bacteria except A. actinomycetemcomitans while the use of SRP alone resulted only in a statistically significant decrease in the numbers of P. gingivalis, T. denticola and T. forsythia.

CONCLUSIONS

In periodontal patients enrolled in a maintenance program one single session of SRP followed by 3x application of aPDT, enhanced the clinical and microbiological outcomes compared to SRP alone.

Comparison of the clinical and microbiological effects of antibiotic therapy in periodontal pockets following laser treatment: An in vivo study

BACKGROUND

Laser technology in periodontal therapy could help in reducing total bacterial count.

OBJECTIVES

The aim of this study was to evaluate the effects of pocket debridement using an erbium-doped yttrium aluminium garnet laser (Er:YAG laser - ERL), scaling and root planing (SRP) with photodynamic therapy (PDT), or SRP alone. Teeth vitality and soft tissue carbonization were also assessed.

MATERIAL AND METHODS

This study included 1,169 single-rooted teeth from 84 patients divided into 3 groups (n = 28). The G1 group had ERL with 40 mJ of energy, a frequency of 40 Hz and a fluence of 63.66 J/cm2. The G2 group had SRP + PDT (635 nm diode laser, 12 J of energy and irradiation time of 30 s) and a Toluidine Blue photosensitizer (PS) (application time of 60 s). The G3 group was administered SRP alone. In the 42 subjects (G1: n = 11, G2: n = 14 and G3: n = 17) with high amounts of Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Treponema denticola (Td) and Tannerella forsythia (Tf), additional 1-week antibiotic treatments with clindamycin or amoxicillin + clavulanic acid - in doses of 600 mg/day or 1000 mg/day, respectively - were prescribed 3 months after the therapy. Microbiological and clinical analyses of the probing depth (PD), recession (RC), plaque index (PI), bleeding on probing (BOP), and attachment loss (AT) were performed at baseline and at the follow-up of 3 months, 3 months and 1 week, and 6 months.

RESULTS

Plaque index decreased in G1 after 3 months, 3 months and 1 week, and 6 months (p < 0.05) and was lower in G1 vs G2 after 3 months (p < 0.05). The reduction in BOP in G1 after 3 months and 1 week was higher in comparison with G2 or G3 (p < 0.02). Probing depth decreased in all groups (p < 0.05). We found a reduction in the percentage of sites with some bacteria after 3 months - Prevotella intermedia (Pi) (G1 and G2), Capnocytophaga gingivalis (Cg) and Eubacterium nucleatum (En) (G3), and after 3 months and 1 week with En, Td, Tf (G1, G2 and G3), Pi (G1 and G2), Aa, Peptostreptococcus micros (Pm), and Cg (G3), and with Pi (G1 and G2), Tf (G2), Pg, En (G2 and G3), and Pm (G3) after 6 months (p < 0.05). We observed no signs of carbonization or teeth injury.

CONCLUSIONS

Scaling and root planing + PDT and ERL may be an alternative therapy for chronic periodontitis.

Effects of Nd:YAG laser irradiation on the growth of Candida albicans and Streptococcus mutans: in vitro study

The purpose of this study was to evaluate the effects of Nd:YAG laser with flat-top handpiece on the in vitro growth of Candida albicans and Streptococcus mutans. The incidence of C. albicans (opportunistic commensal) and S. mutans (facultatively anaerobic) infections is increasing, despite available treatments. Cultures of Streptococcus mutans and Candida albicans were irradiated using Nd:YAG laser (LightWalker, Fotona) with flat-top handpiece (Genova, LightWalker, Fotona) at the following parameters: group G1: 0.25 W, 10 Hz, 15 s, 3 J and group G2: 1 W, 10 Hz, 60s, 59 J. The results were evaluated directly and 24 h after irradiation using a quantitative culture method (estimation of colony-forming units in 1 ml of suspension, cfu/ml), and microscopic analysis with Janus green stain and compared with control group in which laser was not applied. C. albicans was reduced by 20 up to 54% for G1, and for G2 by 10 up to 60% directly after the application. The cfu/ml values for S. mutans decreased by 13% (p = 0.1771) for G1 and 89% (p < 0.0001) for G2. In both test groups 24 h after the application, the number of colony-forming units decreased by 15–46% for G1 and by 15–64% for G2. The arrested cell division, increasing the surface area and increasing the number of metabolically inactive cells, were observed in morphometric analysis. Macroscopic and microscopic analyses revealed a reduction in cell number and a significant decrease of cell metabolism after laser application for both C. albicans and S. mutans.

Er:YAG Laser for Metal and Ceramic Bracket Debonding: An In Vitro Study on Intrapulpal Temperature, SEM, and EDS Analysis

OBJECTIVE

To evaluate the effects of bracket removal using an erbium laser on the pulp temperature and enamel surface.

BACKGROUND

Removal of orthodontic brackets with conventional debonding pliers may result in enamel cracks. To avoid damage to the enamel surface and effectively remove metal or ceramic brackets, different types of lasers, such as Nd:YAG, CO₂, TM:YAP, diode laser, or Er:YAG, have been introduced for debonding.

MATERIALS AND METHODS

A total of 55 brackets (n = 55; 20 metal and 35 ceramic ones) were bonded to 55 caries-free premolars extracted for orthodontic indications. Brackets were irradiated with Er:YAG laser (Morita, Irvine, CA) with a wavelength of 2940 nm at a power of 3.4 W, energy 170 mJ, frequency 20 Hz, pulse duration 300 μs, tip diameter 0.8 mm, air/fluid cooling 3 mL/s, and time of irradiation: 6 sec. Debonding was made by scanning (n = 15; 6 sec irradiation at distance of 2 mm from the bracket with an "S" shape movement) and circular (n = 15; 6 sec irradiation at distance of 1 mm from the bracket) motion technique in ceramic brackets or the circular motion technique in metal brackets (n = 15). The number of 10 nonirradiated teeth with ceramic (n = 5) or metal brackets (n = 5) was used as a control in SEM test and EDS analysis. The damage in tooth enamel surface and the calcium percentage were analyzed by means of scanning electron microscope (JEOL 6610LV, JEOL, Japan) and energy dispersive X-ray spectroscopy (EDS, Oxford, United Kingdom). Temperature changes in the pulp were measured by K-type thermocouple. Evaluation of the Adhesive Remnant Index (ARI) on the enamel surface of each tooth was examined after bracket debonding.

RESULTS

The scanning method has caused significantly lower temperature increase (mean: 0.83°C) compared with circular motion technique around the ceramic brackets (mean: 1.78°C; p = 0.0001) or the metal brackets (mean: 1.29°C; p = 0.015). ARI score showed no differences between the study groups (p = 0.57). SEM analysis revealed no cracks on enamel surface after laser-assisted debonding in comparison with the control samples where cracks were found. EDS showed a higher mean percentage of the calcium (30.7-85.8%) for all test groups compared with control samples (mean: 7%; p = 0.0002). The amount of the calcium elements was higher for metal brackets in comparison with ceramic ones (p = 0.0002).

CONCLUSIONS

Er:YAG laser-assisted debonding causes a minor increase in the pulp temperature and reduced the risk of enamel damage compared with conventional bracket removal.

Tooth development disorders in infants of rat dams exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin and protective role of tocopherol and acetylsalicylic acid

Aryl hybrocardon receptor (AhR) activation plays a key role in the pathomechanism of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced defective spatial structure of teeth caused by disordered collagen synthesis. The aim of this study was to identify the influence of dioxins present in female Buffalo rats on the dental structure of their offspring's in the neonatal period and the potential of α-tocopherol and acetylsalicylic acid in curbing post-dioxin hard tissue defects. Research material consisted of molar teeth (n=40) of rat pups which had been given a single dose of TCDD and were then treated with tocopherol or acetylsalicylic acid for 3 weeks. In the offspring of rat dams exposed to TCDD, ameloblasts and odontoblasts were less developed in comparison with the control group and less dynamic angiogenesis in the area of dental papilla was observed. In the pups of TCDD-exposed mothers, a smaller number of AhR was found in amelogenic and odontoblastic cells, whereas in the pups of mothers exposed to TCDD followed by tocopherol and acetylsalicylic acid treatment, the expression of AhR in ameloblasts and odontoblasts increased. We conclude that tocopherol and acetylsalicylic acid treatment exerts a protective effect on the TCDD-induced structural defects of tooth tissue.

Histological and Thermometric Examination of Soft Tissue De-Epithelialization Using Digitally Controlled Er:YAG Laser Handpiece: An Ex Vivo Study

OBJECTIVE

The purpose of this study was histological and thermometric examination of soft tissue de-epithelialization using digitally controlled laser handpiece (DCLH) - X-Runner.

BACKGROUND DATA

Commonly used techniques for de-epithelialization include scalpel, abrasion with diamond bur, or a combination of the two. Despite being simple, inexpensive and effective, these techniques are invasive and may produce unwanted side effects. It is important to look for alternative techniques using novel tools, which are minimally invasive and effective.

MATERIALS AND METHODS

114 porcine samples sized 6 × 6 mm were collected from the attached gingiva (AG) of the alveolar process of the mandible using 15C scalpel blade. The samples were irradiated by means of Er:YAG laser (LightWalker, Fotona, Slovenia), using X-Runner and HO₂ handpieces at different parameters; 80, 100, and 140 mJ/20 Hz in time of 6 or 16 sec, respectively. The temperature was measured with a K-type thermocouple. For the histopathological analysis of efficiency of epithelium removal and thermal injury, 3 random samples were de-epithelialized with an HO₂ handpiece, and 9 random samples with an X-Runner handpiece with different parameters. For the samples irradiated with DCLH, we have used three different settings, which resulted in removing 1 to 3 layers of the soft tissue. The efficiency of epithelium removal and the rise of temperature were analyzed.

RESULTS

DCLH has induced significantly lower temperature increase compared with HO₂ at each energy to frequency ratio. The histological examination revealed total epithelium removal when HO₂ handpiece was used at 100 and 140 mJ/20 Hz and when DCLH was used for two- and threefold lasing at 80, 100, and 140 mJ/20 Hz.

CONCLUSIONS

Er:YAG laser with DCLH handpiece may be an efficient tool in epithelium removal without excessive thermal damage.

Er:YAG laser, piezosurgery, and surgical drill for bone decortication during orthodontic mini-implant insertion: primary stability analysis-an animal study

It is important to identify factors that affect primary stability of orthodontic mini-implants because it determines the success of treatment. We assessed mini-implant primary stability (initial mechanical engagement with the bone) placed in pig jaws. We also assessed mini-implant insertion failure rate (mini-implant fracture, mini-implants to root contact). A total of 80 taper-shaped mini-implants (Absoanchor® Model SH1312-6; Dentos Inc., Daegu, Korea) 6 mm long with a diameter of 1.1 mm were used. Bone decortication was made before mini-implant insertion by means of three different methods: Group G1: Er:YAG laser (LiteTouch®, Light Instruments, Yokneam, Israel) at energy of 300 mJ, frequency 25 Hz, fluence 38.2 J/cm2, cooling 14 ml/min, tip 1.0 × 17 mm, distance 1 mm, time of irradiation 6 s; Group G2: drill (Hager & Meisinger GmbH, Hansemannstr, Germany); Group G3: piezosurgery (Piezotom Solo, Acteon, NJ, USA). In G4 group (control), mini-implants were driven by a self-drilling method. The primary stability of mini-implants was assessed by measuring damping characteristics between the implant and the tapping head of Periotest device (Gulden-Medizinteknik, Eschenweg, Modautal, Germany). The results in range between − 8 to + 9 allowed immediate loading. Significantly lower Periotest value was found in the control group (mean 0.59 ± 1.57, 95% CI 0.7, 2.4) as compared with Er:YAG laser (mean 4.44 ± 1.64, 95% CI 3.6, 5.3), piezosurgery (mean 17.92 ± 2.73, 95% CI 16.5, 19.3), and a drill (mean 5.91 ± 1.52, 95% CI 5.2, 6.6) (p < 0.05). The highest failure rate (33.3%) during mini-implant insertion was noted for self-drilling method (G4) as compared with G1, G2, and G3 groups (p < 0.05). The small diameter decortication by Er:YAG laser appeared to provide better primary stability as compared to drill and piezosurgery. Decortication of the cortical bone before mini-implant insertion resulted in reduced risk of implant fracture or injury of adjacent teeth. The high initial stability with a smaller diameter of the mini-implant resulted in increased risk of fracture, especially for a self-drilling method.

Release of bisphenol A and its derivatives from orthodontic adhesive systems available on the European market as a potential health risk factor

INTRODUCTION

Treatment with fixed orthodontic appliances requires the application of adhesive systems to enable secure fastening of brackets and retainers to the surface of tooth enamel. The orthodontic bonding systems are similar in terms of chemical composition to dental filling materials, the chemical stability of which is not satisfactory. Particularly alarming is the release of bisphenol A and its derivatives to the external environment, which has been well-documented for materials used in conservative dentistry.

OBJECTIVES

The aim of the study was an in vitro assessment of the release of biologically harmful bisphenol A and its derivatives from orthodontic adhesives available on the European market, as a potential health risk factor for orthodontic patients.

MATERIAL AND METHODS

The study assessed levels of BPA, BPA polymers and Bis-GMA resin in eluates of six commonly used orthodontic adhesives: Light Bond, Transbond XT, Resilence, Aspire, GrĕnGloo and ConTec LC, obtained after one hour, 24 hours, 7 days and 31 days of material sample storage in water. The presence and concentration of the studied chemicals in the obtained solutions were identified using the HPLC method.

RESULTS

The highest (p≤0.05) concentration of BPA at 32.10µg/ml was observed in the Resilence material eluates. The highest concentration of poly-bisphenol A was found in solutions obtained after incubation of ConTec LC adhesive at 371.90µg/ml, whereas the highest amount of Bis-GMA resin (425.07µg/ml) was present in Aspire material eluates.

CONCLUSIONS

1) In conditions of the current experiment it was demonstrated that most of the assessed orthodontic adhesive resins available on the European market and released into the outside environment - biologically harmful bisphenol A or its derivatives, posing a potential threat to the patients' health. 2) Release of BPA and its derivatives into aqueous solutions is the highest in the early stages of sample incubation.

[The influence of selected plants on the tobacco smoking-induced effects in the oral cavity--review]

Tobacco smoking is a culprit of many pathological lesions on the oral mucosa. In this literature review we focused on various therapeutic options for tobacco induced mucosal pathologies. Many active ingredients of Aloe vera, Chamomile, Curcuma longa and Calendula show potent anti-inflammatory and regenerative activity, making plant derived drugs a reasonable option for traditional pharmaceuticals.