Peri-implant diseases: a review of treatment interventions

Anti-biofilm properties of laser-synthesized, ultrapure silver-gold-alloy nanoparticles against Staphylococcus aureus

Staphylococcus aureus biofilm-associated infections are a common complication in modern medicine. Due to inherent resilience of biofilms to antibiotics and the rising number of antibiotic-resistant bacterial strains, new treatment options are required. For this purpose, ultrapure, spherical silver-gold-alloy nanoparticles with homogenous elemental distribution were synthesized by laser ablation in liquids and analyzed for their antibacterial activity on different stages of S. aureus biofilm formation as well as for different viability parameters. First, the effect of nanoparticles against planktonic bacteria was tested with metabolic activity measurements. Next, nanoparticles were incubated with differently matured S. aureus biofilms, which were then analyzed by metabolic activity measurements and three dimensional live/dead fluorescent staining to determine biofilm volume and membrane integrity. It could be shown that AgAu NPs exhibit antibacterial properties against planktonic bacteria but also against early-stage and even mature biofilms, with a complete diffusion through the biofilm matrix. Furthermore, AgAu NPs primarily targeted metabolic activity, to a smaller extend membrane integrity, but not the biofilm volume. Additional molecular analyses using qRT-PCR confirmed the influence on different metabolic pathways, like glycolysis, stress response and biofilm formation. As this shows clear similarities to the mechanism of pure silver ions, the results strengthen silver ions to be the major antibacterial agent of the synthesized nanoparticles. In summary, the results of this study provide initial evidence of promising anti-biofilm characteristics of silver-gold-alloy nanoparticles and support the importance of further translation-oriented analyses in the future.

Predictive factors for the treatment success of peri-implantitis: a protocol for a prospective cohort study

INTRODUCTION

Peri-implantitis, a common biological complication of dental implant, has attracted considerable attention due to its increasing prevalence and limited treatment efficacy. Previous studies have reported several risk factors associated with the onset of peri-implantitis (eg, history of periodontitis, poor plaque control and smoking). However, inadequate data are available on the association between these risk factors and successful outcome after peri-implantitis therapy. This prospective cohort study aims to identify the local and systemic predictive factors for the treatment success of peri-implantitis.

METHODS AND ANALYSIS

A single-centre cohort study will be conducted by recruiting 275 patients diagnosed with peri-implantitis. Sociodemographic variables, healthy lifestyles and systemic disorders will be obtained using questionnaires. In addition, clinical and radiographic examinations will be conducted at baseline and follow-up visits. Treatment success is defined as no bleeding on probing on more than one point, no suppuration, no further marginal bone loss (≥0.5 mm) and probing pocket depth ≤5 mm at the 12-month follow-up interval. After adjustment for age, sex and socioeconomic status, potential prognostic factors related to treatment success will be identified using multivariable logistic regression models.

ETHICS AND DISSEMINATION

This cohort study in its current version (2.0, 15 July 2022) is in accordance with the Declaration of Helsinki and was approved by the Ethics Committee of Stomatological Hospital, Southern Medical University (EC-CT-(2022)34). The publication will be on behalf of the study site.

TRIAL REGISTRATION NUMBER

ChiCTR2200066262.

Short-term influence of antimicrobial photodynamic therapy as an adjuvant to mechanical debridement in reducing soft-tissue inflammation and subgingival yeasts colonization in patients with peri-implant mucositis

OBJECTIVE

The objective of this short-term follow-up study was to evaluate the influence of antimicrobial photodynamic therapy (aPDT) as an adjuvant to mechanical debridement (MD) in reducing soft-tissue inflammation and subgingival yeasts colonization (SYC) in patients with peri‑implant mucositis (PiM).

METHODS

Individuals diagnosed with PiM were included. Demographic data was collected using a questionnaire. Peri-implant plaque index (PI), bleeding index (BI), probing depth (PD), crestal bone levels and SYC were measured at baseline. Therapeutically, these individuals were divided into test and control groups. In the control-group patients underwent MD and in the test-group patients underwent MD with adjunct single session of aPDT. Clinical peri‑implant parameters and SYC were reassessed after 12-weeks. Correlation between age, gender and duration of implants with SYC and clinical peri‑implant status was assessed using logistic regression models. P < 0.05 was selected as an indicator of statistical significance.

RESULTS

The test and control-groups comprised of 24 and 23 individuals, respectively. In the test and control groups, toothbrushing twice daily was reported by 7 (29.2%) and 5 (21.7%) individuals, respectively. None of the individuals had ever used a dental floss. At baseline, there was no difference in peri‑implant PI, BI, PD and CBL in the test and control groups. At follow-up, peri‑implant PI (P < 0.01), BI (P < 0.01) and PD (P < 0.01) were significantly higher in the control compared with the test-group. At baseline, SYC in the test and control groups were 1865.3 ± 403.4 CFU/ml and 1963.7 ± 512.4 CFU/ml, respectively. At 90 days' follow-up, SYC in the test and control groups were 1472 ± 202.7 and 1538.4 ± 331.7 CFU/ml, respectively. There was no significant difference in SYC in both groups when baseline values were compared with 90 days' follow-up.

CONCLUSION

One session of aPDT after MC with adjunct aPDT is effective in reducing soft tissue inflammation but not SYC in patients with PiM.

Strength of titanium-zirconium alloy implants with a conical connection after implantoplasty

STATEMENT OF PROBLEM

Peri-implantitis occurs around dental implants, and implantoplasty has been used to address this ongoing disease; however, the changes to the physical properties of an implant after implantoplasty have not been well documented.

PURPOSE

The purpose of this in vitro study was to determine the effect of implantoplasty on fracture strength and the load required for plastic deformation after cyclic fatigue on dental implants.

MATERIAL AND METHODS

Twenty-six titanium/zirconium (TiZr) alloy implants (Roxolid Bone Level Implant; 4.1×10 mm) were embedded with 50% thread exposure and divided into 4 groups based on whether they had implantoplasty treatment by using different diamond rotary instruments and/or cyclic loading at 250 N for 2 million cycles: C0 (control, no cyclic loading), T0 (test, no cyclic loading), CM (control, cyclic loading), and TM (test, cyclic loading). After implantoplasty and/or cyclic loading, all implants underwent a load-to-failure test. The maximum fracture strength (FS) and load required for the onset of plastic deformation (PD) were recorded in Newtons. One-way ANOVA and nonparametric comparisons with control by using the Dunn and Wilcoxon method for joint ranking were used for statistical analysis.

RESULTS

The mean ±standard deviation FS for C0, CM, T0, and TM was 1465.2 ±86.4 N, 1480.7 ±64.1 N, 1299.3 ±123.8 N, and 1252.1 ±85.7 N, respectively. The mean ±standard deviation load for onset of PD for C0, CM, T0, and TM was 860.2 ±88.1 N, 797.0 ±130.5 N, 776.5 ±181.8 N, and 631.3 ±84.5 N, respectively. The TM group had a significantly lower FS and PD than the C0, CM, and T0 groups (P<.05) CONCLUSIONS: Both fracture strength (FS) and the onset of plastic deformation (PD) were significantly reduced after a TiZr alloy implant received implantoplasty and cyclic loading.

Influence of the Available Surface Area and Cell Elasticity on Bacterial Adhesion Forces on Highly Ordered Silicon Nanopillars

Initial bacterial adhesion to solid surfaces is influenced by a multitude of different factors, e.g., roughness and stiffness, topography on the micro- and nanolevel, as well as chemical composition and wettability. Understanding the specific influences and possible interactive effects of all of these factors individually could lead to guidance on bacterial adhesion and prevention of unfavorable consequences like medically relevant biofilm formation. On this way, the aim of the present study was to identify the specific influence of the available surface area on the adhesion of clinically relevant bacterial strains with different membrane properties: Gram-positive Staphylococcus aureus and Gram-negative Aggregatibacter actinomycetemcomitans. As model surfaces, silicon nanopillar specimens with different spacings were fabricated using electron beam lithography and cryo-based reactive ion etching techniques. Characterization by scanning electron microscopy and contact angle measurement revealed almost defect-free highly ordered nanotopographies only varying in the available surface area. Bacterial adhesion forces to these specimens were quantified by means of single-cell force spectroscopy exploiting an atomic force microscope connected to a microfluidic setup (FluidFM). The nanotopographical features reduced bacterial adhesion strength by reducing the available surface area. In addition, the strain-specific interaction in detail depended on the bacterial cell's elasticity and deformability as well. Analyzed by confocal laser scanning microscopy, the obtained results on bacterial adhesion forces could be linked to the subsequent biofilm formation on the different topographies. By combining two cutting-edge technologies, it could be demonstrated that the overall bacterial adhesion strength is influenced by both the simple physical interaction with the underlying nanotopography and its available surface area as well as the deformability of the cell.

Laser Treatment of Peri-Implantitis: A Systematic Review of Radiographic Outcomes

(1) Background: This systematic review aimed to evaluate the effects of laser therapy on radiographic bone level (RBL) changes in peri-implantitis defects. (2) Methods: A literature search with defined inclusion criteria was performed. PubMed, Web of Science, Cochrane Library, and Google Scholar were searched through September 2020. The evaluated primary outcomes were RBL changes. In studies that reported RBL data, corresponding secondary clinical outcomes were probing depth (PD), bleeding on probing (BOP), and clinical attachment level (CAL). (3) Results: Thirteen articles were selected for data extraction and risk of bias assessment. Eight studies showed evidence of RBL gain in the laser groups compared to baseline, but did not report the statistical significance. Eight of these 13 studies reported comparisons to control. Five of the eight studies did not show RBL gain in the laser groups compared to control. In the laser groups compared to baseline, 11 of 13 reported reduced PD, and 6 of 13 reported significantly reduced BOP. Compared to the control, eight of the eight reported reduction of PD, and three of six reported significantly reduced BOP. Statistical significance was not consistently reported. (4) Conclusions: Within the limits of this systematic review, laser treatment may promote bone gain in peri-implantitis defects, may reduce BOP and PDs, and may be comparable to mechanical therapy. However, definitive conclusions can only be made with statistically significant data, which were found lacking in the currently available studies. This systematic review was registered with the National Institute for Health Research, international prospective register of systematic reviews (PROSPERO): CRD42020207972.

Peri-implant health after supportive mucositis therapy is associated with increased levels of FGF-2

This study aimed to analyze Fibroblast Growth Factor-2 (FGF-2) levels in the peri-implant crevicular fluid throughout supportive mucositis therapy. Twenty-six participants with Branemark protocol prosthesis were divided into two groups: the control group, characterized by healthy peri-implants, and the mucositis group, presenting a diagnosis of peri-implant mucositis. All participants underwent clinical examination, radiographic analysis, prosthesis removal, and non-invasive peri-implant therapy (mechanical debridement associated with chlorhexidine 0.12%) during a period of 36 days divided into three intervals. Peri-implant crevicular fluid samples were collected at each interval in order to analyze FGF-2 levels by immuno-enzymatic assay. The control and mucositis groups showed difference in keratinized mucosa. The smaller the range of keratinized mucosa the higher susceptibility of peri-implant mucositis. Throughout the treatment intervals, participants were diagnosed in different groups indicating whether or not the non-invasive therapy was able to treat peri-implant mucositis. There was a significant difference of FGF-2 levels between groups, with the higher FGF-2 levels in the control group (p=0.01). After supportive therapy, the mucositis group showed significantly increased FGF-2 levels (p<0.01) compared to initial levels. After 36 days of supportive therapy, there was a reduction of peri-implant mucositis from 70% to 23%. Clinical and laboratory outcomes showed a clear correlation since FGF-2 levels increased after 36 days. It was concluded that the therapy protocol was effective and promoted a regenerative reaction and FGF-2 can be considered a future target for peri-implant mucositis understanding.

Effectiveness of antimicrobial photodynamic therapy as an adjunct to mechanical instrumentation in reducing counts of Enterococcus faecalis and Candida albicans from C-shaped root canals

BACKGROUND/PURPOSE

The aim was to assess the effectiveness of antimicrobial photodynamic therapy (aPDT) as an adjunct to mechanical instrumentation (MI) in reducing Enterococcus faecalis (E faecalis) and Candida albicans (C albicans) counts from C-shaped root-canals.

METHODS

Teeth with C-shaped canals as identified on cone beam computed tomographic images were included. Following incubation with E faecalis and C albicans, samples were divided into 4 groups a four follows: Group-1: MI with adjunct aPDT; Group-2: aPDT alone; Group-3: MI alone; and Group-4: no treatment. The pulp chambers of these teeth were exposed and coronal pulp was mechanically derided using sterile endodontic excavators. Using flexible files, all canals were debrided up to size #30 K-files with intermittent irrigation with 2.5% sodium hypochlorite irrigation. In Groups 1 and 3, methylene-blue was injected in all canals and aPDT was performed using a 600 nm diode laser. Sample-size estimation was done on data from a pilot investigation and group-comparisons were done using one way analysis of variance and Bonferroni post-hoc adjustment tests. P < .05 was considered statistically significant.

RESULTS

Sixty periodontally hopeless mandibular second molars with C-shaped canals were included. There was a statistically significant reduction CFU/mL of E faecalis (P < .001) and C albicans (P < .001). At post-operative microbial assessments in Group-1. There was no difference CFU/mL of E faecalis and C albicans at post-operative microbial assessments in Groups 2-4.

CONCLUSION

MI with adjunct aPDT is more effective in reducing count of E faecalis and C albicans from C-shaped root canals.

Effect of multiple sessions of photodynamic therapy on bone regeneration around dental implants among patients with peri-implantitis

OBJECTIVE

The aim of the present study was to assess the effect of multiple sessions of antimicrobial photodynamic therapy (aPDT) on bone regeneration around dental implants among patients with peri-implantitis.

METHODS

Patients with peri-implantitis were included. Therapeutically, patients were randomly divided into 4 groups: (a) Group-I: Mechanical debridement (MD) alone; (b) Group-II: MD at baseline followed by a single session of adjunct a PDT; (c) Group-III: MD at baseline followed by aPDT at baseline and at 3-months of follow-up; and Group-IV: MD at baseline followed by aPDT at baseline and at 3- and 6-months of follow-up. Demographic data was collected and peri-implant clinical (plaque index [PI], gingival index [GI], and probing depth [PD]) and radiographic (crestal bone loss [CBL]) parameters were assessed at baseline and after 9 months. Sample-size estimation was done on data from a pilot investigation and group comparisons were done using one-way analysis of variance and Bonferroni post-hoc adjustment tests. Level of significance was set at P<0.01.

RESULTS

Twenty-two, 22, 22 and 22 patients with peri-implantitis were enrolled in groups -I, -II, -III and -IV. The mean age of individuals in groups -I, -II, -III and -IV were 59.2 ± 5.3, 60.5 ± 2.8, 59.6 ± 3.1 and 58.7 ± 0.8 years, respectively. Compared with Group-I, there was a statistically significant reduction in PI (P<0.01), GI (P<0.01) and PD (P<0.01) in all groups at 9-months follow-up. There was no significant difference in PI, GI and PD in groups -II, -III and -IV at 9-months follow-up. There was no statistically significant difference in CBL in all groups at baseline and at 9-months-follow-up.

CONCLUSION

The use of aPDT as an adjunct to MD reduces the severity of peri-implant mucositis but does not contribute towards bone regeneration in peri-implant osseous defects.

The effect of conventional versus electronic cigarette use on treatment outcomes of peri-implant disease

Aim

To compare changes in clinical periodontal parameters (gingival consistency, colour, BOP, PI, PD) and changes of salivary inflammatory biomarkers (IL-1 β, IL-6, MMP-8, TNF- α and TIMP-1 between conventional, electronic cigarette smokers and non-smokers after peri-implant treatment.

Methods

Study participants were grouped into three groups (i) Conventional cigarette smokers (ii) Electronic cigarette smokers and (iii) non-smokers respectively. A total of 60 adult patients aged (40–56 years) with 60 implants with active per-impantitis was included.Clinical and Biological parameters were evaluated before surgical treatment at baseline, one, six and twelve month post treatment. Pearson’s chi-square test was used to compare the distribution of the categorical while Two-way repeated analysis of variance was used to compare the mean values of quantitative outcome variables among all study groups across the 4 time points.

Results

A total of 60 subjects (60 implants) were selected and classified into three groups as per their smoking method 20 participants in each group with one single targeted implant diagnosis with active peri-implantitis. The gingival colour, the change was statistically significant at one year of post treatment.The gingival consistency distribution across the three groups is not statistically significant at baseline, but it is statistically significant at one-month (p = 0.001), six months (p = 0.029) and at the completion of one-year (p = 0.018) post treatment. The plaque index of 100% of non-smokers had changed to ‘0’ and 35% change in cigarettes and 30% change in electronic smokers which is statistically significant (p = 0.016).The prevalence of BOP was observed in the three groups as 72%, 76.5% and 88.9% at baseline. The mean values of PD have shown statistically significant change across the three groups over the four-time intervals of observation (p = 0.024). The comparison of mean values of IL-1 β, IL-6 and TIMP-1 has shown statistically significant change across the three groups over the four intervals of observation (p < 0.0001).

Conclusions

Electronic cigarette smoking was found to be most prevalent risk indicator for peri-implantitis. Compromised response of peri-implantitis treatment both clinically and biologically was found more among electronic cigarette smokers when compared to conventional cigarette smokers and non-smokers.

Trial registration: This case-control study was conducted at King Saud University’s Dental College, Riyadh, Saudi Arabia, in accordance with “Helsinki Declaration of Human Studies” and approved by the Institutional Review Board (Reference no: 87563).

Comparison of photobiomodulation and photodynamic therapy as adjuncts to mechanical debridement for the treatment of peri-implantitis

BACKGROUND AND OBJECTIVE

The aim of this study was to compare the efficacy of photobiomodulation therapy (PBMT) and photodynamic therapy (PDT) as adjuncts to mechanical debridement (MD) for the treatment of peri-implantitis. The present study is based on the null hypothesis that there is no difference in the peri-implant inflammatory parameters (modified plaque index [mPI], modified gingival index [mGI], probing depth [PD]) and crestal bone loss (CBL) following MD either with PBMT or PDT in patients with peri-implantitis.

METHODS

Forty-nine patients with peri-implantitis were randomly categorized into three groups. In Groups 1 and 2, patients underwent MD with adjunct PBMT and PDT, respectively. In Group 3, patients underwent MD alone (controls). Peri-implant inflammatory parameters were measured at baseline and 3-months follow-up. P-values < 0.01 were considered statistically significant.

RESULTS

At baseline, peri-implant clinicoradiographic parameters were comparable in all groups. Compared with baseline, there was a significant reduction in mPI (P< 0.001), mGI (P< 0.001) and PD (P< 0.001) in Groups 1 and 2 at 3-months follow-up. In Group 3, there was no difference in the scores of mPI, mGI and PD at follow-up. At 3-months follow-up, there was no difference in mPI, mGI and PD among patients in Groups 1 and 2. The mPI (P< 0.001), mGI (P< 0.001) and PD (P< 0.001) were significantly higher in Group 3 than Groups 1 and 2. The CBL was comparable in all groups at follow-up.

CONCLUSION

PBMT and PDT seem to be useful adjuncts to MD for the treatment of peri-implant soft-tissue inflammation among patients with peri-implantitis.

Effect of tongue piercing on periodontal and peri-implant health: A cross-sectional case-control study in adults

OBJECTIVES

The authors hypothesize that periodontal and peri-implant inflammatory parameters are poorer in adult patients with tongue piercing compared with controls. The aim was to assess the influence of tongue piercing on periodontal and peri-implant health status in adults.

METHODS

Test and control groups comprised of individuals with and without tongue piercing, respectively. A questionnaire was used to collect information about gender, age, duration of tongue piercing and implants in function, jaw location of the implant, reasoning for wearing the tongue ornament, and oral hygiene and ornament cleaning habits. Full-mouth and peri-implant plaque index (PI), gingival index (GI), clinical attachment loss (CAL), probing depth (PD) and marginal/crestal bone loss (MBL and CBL, respectively) on mesial and distal surfaces of teeth/implants were recorded. The material (plastic or metal) from which, the bar and ball-ends of the ornament were fabricated was also recorded. A p < 0.01 was considered statistically significant.

RESULTS

Forty-eight and 49 individuals were included in the test and control groups, respectively. There was no difference in PI, GI, PD, CAL and MBL (mesial and distal) among individuals in the test and control groups. In the test group, peri-implant PI (p < 0.01), GI (p < 0.01), PD (p < 0.01) and mesial (p < 0.01) and distal (p < 0.01) CBL were significantly higher in the anterior mandible compared with implants in other jaw locations. In the control group, there was no difference in peri-implant PI, GI, PD and CBL around implants placed in both jaws.

CONCLUSION

Wearing tongue piercings could increase the risks of periodontal and peri-implant diseases particularly in the mandibular anterior segment.

Dentists' preferences in implant maintenance and hygiene instruction

BACKGROUND

This study investigated the preferences of dentists in Australia in providing professional implant maintenance and implant-specific oral hygiene instructions (OHI).

METHODS

General dentists were surveyed online about their preferences in peri-implant diagnostics, maintenance provision, armamentarium used, and implant OHI techniques and frequency.

RESULTS

Most of the 303 respondents (96%) provided maintenance services; 87.6% reviewed implants regularly while 10.7% only performed diagnostics after detecting clinical signs/symptoms. Supragingival prosthesis cleaning was performed by 77.9% of respondents, 35.0% performed subgingival debridement, 41.9% treated peri-implant mucositis and 18.2% treated peri-implantitis. About 15% did not treat nor refer peri-implant disease, including significantly more non-implant providers and dentists without implant training. Maintenance armamentarium commonly included floss (76.3%), prophylaxis (73.9%), plastic curettes (43.3%) and stainless-steel ultrasonics (38.0%). Brushing (86.5%), flossing (73.9%) and interdental brush use (68.3%) were most commonly recommended. Implant OHI was repeated routinely by 57.4% of dentists who provided it. Dentists with greater implant training and experience were more likely to perform reviews and complex maintenance procedures.

CONCLUSIONS

Peri-implant diagnostics performed, treatments provided and armamentarium varied among dentists. Implant providers and those with higher levels of training had more preventative approaches to implant OHI. Possible shortcomings in disease management and OHI reinforcement were identified.

Efficacy of antibiotic versus probiotics as adjuncts to mechanical debridement for managing peri-implant mucositis

The objective was to compare the efficiency of probiotic (PT) versus antibiotic therapy (AT) as adjuvants to non-surgical-mechanical debridement (NSMD) in the treatment of peri-implant mucositis (Pi-M). Volunteers with Pi-M were encompassed. Therapeutically, patients were randomly divided into 3-groups: (a) Group-1: NSMD + PT; (b) Group-2: NSMD + AT; and (c) Group-3: NSMD alone. Peri-implant plaque index (P.I), bleeding on probing (B.O.P), probing depth (P.D) and crestal-bone-loss (C.B.L) were recorded at baseline and at 3-and 6-months follow-up. P<0.05 was selected as the indicator of statistical significance. Forty-two male individuals (14, 14 and 14 in groups 1, 2 and 3, respectively) were included. At 3- and 6-months of follow-up, P.I (P<0.01), B.O.P (P<0.01) and P.D (P<0.01) were higher in Group-2 than Group-1. At 3-months of follow-up, P.I (P<0.01), B.O.P (P<0.01) and P.D (P<0.01) were higher in Group-3 than Group-2. At 6-months of follow-up, P.I, B.O.P and P.D were comparable in groups 2 and 3. In Group-3, P.I, B.O.P and P.D were comparable with the respective baseline values at 6-months of follow-up. The C.B.L in all groups remained unchanged up to 6-months of follow-up. The NSMD with adjuvant PT is more effective than adjunct AT in the treatment of Pi-M for up to 3-months.

Role of antimicrobial photodynamic therapy in reducing whole salivary oral yeasts colonization in type-2 diabetic and non-diabetic patients with and without dental implants

OBJECTIVE

The aim was to assess the impact of antimicrobial photodynamic therapy (aPDT) in reducing whole salivary oral yeasts colonization in type-2 diabetic and non-diabetic patients with dental implants.

METHODS

Type-2 diabetic and self-reported non-diabetic patients were included. Participants were divided into the following groups: Group-1: Type-2 diabetic patients with dental implants; Group-2: Non-diabetic patients with dental implants; Group-3: Type-2 diabetic patients without dental prostheses; Group-4: Non-diabetic patients without dental prostheses. In each group, participants were subdivided into 2-sub-groups. In the test-subgroup, participants received routine oral hygiene maintenance instructions (OHMI) and underwent full mouth disinfection using aPDT; and in the control-group, participants received OHMI alone. Unstimulated whole saliva samples were collected, hemoglobin A1c levels were measured and yeast colonization was assessed at baseline and at 3-months' follow-up in all groups. Sample-size estimation was done and group-comparisons were done. P-values <0.01 were considered statistically significant.

RESULTS

At baseline, the mean oral yeasts colonization was significantly higher among patients in Group-1 (P < 0.001) and 3 (P < 0.001) compared with individuals in groups 2 (P < 0.001) and 4 (P < 0.001). At baseline and at 3-months of follow-up, the mean HbA1c levels and oral yeasts colonization were significantly higher among patients in Group-1 (P < 0.001) and 3 (P < 0.001) compared with individuals in groups 2 (P < 0.001) and 4 (P < 0.001).

CONCLUSION

In the short-term, routine OHMI with adjunct aPDT is more effective in reducing whole salivary oral yeasts counts than OHMI alone in patients with and without dental implants.

Antibacterial effectiveness of scaling and root planing with and without photodynamic therapy against Campylobacter rectus counts in the oral biofilm of patients with periodontitis

BACKGROUND

It is hypothesized that scaling and root planning (SRP) with adjunct photodynamic therapy (PDT) is more effective in reducing Campylobacter rectus (C. rectus) from the oral biofilm (OB) among patients with periodontitis, than SRP alone. The objective was to compare the effectiveness of SRP with and without adjunct PDT in reducing OB C. rectus counts of patients with periodontitis.

METHODS

Chronic gastritis patients diagnosed with periodontitis were included. Therapeutically, the patients were divided into 2-groups. Patients in the test- and control-groups underwent SRP with and without adjunct PDT, respectively. In both groups, full-mouth plaque index (PI), bleeding on probing (BOP), probing depth (PD) and marginal bone loss (MBL) were measured and subgingival OB counts of C. rectus were measured at baseline and 12-weeks after treatment. Data normality was assessed and group-comparisons were done using the paired t-test and Man-Whitney U tests. A type-1 error rate of 5 % was used.

RESULTS

Thirty patients with periodontitis were included. All patients had Grade-B/Stage-II periodontitis. All participants were male with no significant difference in age. At baseline PI, BOP, PD and MBL were comparable in both groups. Counts of C. rectus in the subgingival OB samples were similar in both groups at baseline. At 12-weeks of follow-up, PI (P < 0.01), GI (P < 0.01) and PD (P < 0.01) were significantly higher in the control- compared with the test-group compared with baseline. The percentages of C. rectus -positive individuals were higher in the control- than the test-group at 12-weeks' (P < 0.01). At 12-weeks' follow-up the percentages of C. rectus -positive patients were comparable with their respective baseline percentages in the control-group.

CONCLUSION

Compared with SRP alone, adjuvant use of PDT is more efficient in eliminating C. rectus in the OB and reducing clinical parameters in patients with grade-B/Stage-II periodontitis.

Prosthodontic Principles in Dental Implantology: Adjustments in a Coronavirus Disease-19 Pandemic-Battered Economy

More patients are requesting fixed prosthesis to replace missing teeth. More than 5 million dental implants are placed annually in the United States. This number will decrease in 2020 owing to the coronavirus disease-19 pandemic. The edentulous patient has a decreased quality of life. Prosthodontic rehabilitation/reconstruction of edentulism improves overall quality of life. Patient-reported outcome measures are subjective reports of patients' perceptions of their oral health status and the impact that it has on their quality of life. This chapter contains a variety of prosthodontic principles for the reader to help satisfy the needs and expectations of the patient.

Role of probiotics for the treatment of peri-implant mucositis in patients with and without type-2 diabetes mellitus

The hypothesis was that probiotic therapy (PT) does not offer additional benefits to mechanical debridement (MD) for treatment of diabetic subjects with peri-implant mucositis (PM). This study compared the influence of PT as an adjunct to MD for the treatment of PM in type2 diabetic and non-diabetic patients over a 12-month follow-up period. Patients with and without type-2 diabetes were encompassed. Based upon treatment-procedure, PM patients were categorized into 2 groups: (a) Non-surgical + PT; and (b) Group-2: Non-surgical MD alone. Demographics and education statuses were recorded. Gingival (GI) and plaque (PI) indices, crestal bone loss (CBL) and probing depth (PD were measured at baseline and after 6- and 12-months. Significant differences were detected with P<0.01. The HbA1c was significantly higher in diabetic patients at all time durations than patients without type-2 diabetes (P<0.001). Baseline GI, PI, PD and CBL) were comparable in all groups. In patients with type-2-diabetes, there was no difference in PI, GI, PD and CBL at 6- and 12-months' follow-up. In patients without type-2 diabetes, there was a significant reduction in PI (P<0.01), GI (P<0.01), and PD (P<0.01) at 6-months and 1-year follow-up than their values at baseline. In patients without type-2 diabetes, MD with or without adjunct PT reduces soft tissue inflammatory parameters in patients with PM.

Peri-Implant Diseases: Diagnosis, Clinical, Histological, Microbiological Characteristics and Treatment Strategies. A Narrative Review

Since the use of dental implants is continuously increasing, it is imperative for dental practitioners to understand the nature and treatment of peri-implant diseases. The purpose of this manuscript is to comprehensively review peri-implant diseases, their characteristics, as well as their non-surgical and surgical treatment. To that end, the current literature was searched and a narrative review was conducted. It is essential that the case definitions described in the 2017 World Workshop on the Classification of Periodontal and Peri-implant Diseases and Conditions are used to diagnose and classify peri-implant health, peri-implant mucositis and peri-implantitis. While recent epidemiologic studies on peri-implant diseases exist, there is great heterogeneity in the definition of these conditions. Several risk factors and indicators are reported in the literature, with smoking and diabetes being the most universally accepted. In peri-implant mucositis, non-surgical treatment seems to be sufficient. However, for the treatment of peri-implantitis, a surgical approach, which includes open-flap debridement, apically positioned flap and guided bone regeneration, is considered more appropriate. A great variety of adjuncts to mechanical treatment have been reported with controversial results. Finally, studies comparing results from different peri-implantitis treatments are warranted in randomized controlled clinical trials in order to provide stronger evidence-based approaches.

Glow Discharge Plasma Treatment on Zirconia Surface to Enhance Osteoblastic-Like Cell Differentiation and Antimicrobial Effects

Peri-implantitis is the pathological condition of connective tissue inflammation and the progressive loss of supporting bone around dental implants. One of the primary causes of peri mucositis evolving into peri-implantitis is bacterial infection, including infection from Porphyromonas gingivalis. Enhancing the surface smoothness of implants helps to prevent P. gingivalis adhesion to the implant’s surface. Interaction analyses between bacteria and the surface roughness of zirconia (Zr) discs subjected to a glow discharge plasma (GDP) treatment compared with non-plasma-treated autoclaved control Zr discs were done. Examinations of the material prosperities revealed that the GDP-treated Zr group had a smoother surface for a better wettability. The GDP-treated Zr discs improved the proliferation of the osteoblast-like cells MG-63, and the osteoblastic differentiation was assessed through alkaline phosphatase detection and marker gene bone sialoprotein (Bsp) and osteocalcin (OC) induction. Scanning electron microscopy demonstrated a relatively low P. gingivalis adhesion on GDP-treated Zr disks, as well as lower colonization of P. gingivalis compared with the control. Our findings confirmed that the GDP treatment of Zr discs resulted in a significant reduction of P. gingivalis adhesion and growth, demonstrating a positive correlation between surface roughness and bacteria adhesion. Therefore, the GDP treatment of Zr dental implants can provide a method for reducing the risk of peri-implantitis.

Expandable Titanium Cages in the Emergent Treatment of Severe Spinal Deformity Secondary to Osteomyelitis: A Series of Three Complex Cases

The literature lacks robust evidence on the benefits versus risks of instrumenting and fusing the spinal column in the setting of active osteomyelitis. We report three patients with vertebral osteomyelitis and subsequent severe and complex kyphotic deformities. Patients 1 and 2 had previous instrumentation that required revision because of hardware failure in the thoracic and thoracolumbar regions, respectively. Patient 3 developed a severe cervical kyphotic deformity at 2 months after being diagnosed and treated with antibiotics for osteomyelitis, necessitating emergent instrumentation and fusion. All the three patients are doing very well so far. Spinal instrumentation and fusion for correction of kyphotic deformity is sometimes necessary in the context of active osteomyelitis and should be done emergently and without hesitation when spinal cord injury from spinal instability is of concern.

Niche Specific Microbiota-Dependent and Independent Bone Loss around Dental Implants and Teeth

Oral mucosal homeostasis is achieved by complex immunologic mechanisms, orchestrating host immunity to adapt to the physiologic functions of the various specialized niches in the oral cavity. Dental implants introduce a novel mucosal niche to the immune system to deal with. Nevertheless, the immune mechanisms engaged toward implants and whether they have broader effects are not well defined. Using a murine model, we found an accumulation of neutrophils and RANKL-expressing T and B lymphocytes in the implant-surrounding mucosa, accompanied by local bone loss. Surprisingly, the presence of implants had an impact on remote periodontal sites, as elevated inflammation and accelerated bone loss were detected in intact distant teeth. This was due to microbial dysbiosis induced by the implants, since antibiotic treatment prevented bone loss around teeth. However, antibiotic treatment failed to prevent the loss of implant-supporting bone, highlighting the distinct mechanisms mediating bone loss at each site. Further analysis revealed that implants induced chronic lymphocyte activation and increased mRNA expression of IFN-α and accumulation of IFN-α–producing plasmacytoid dendritic cells, which we previously reported as bone-destructive immune responses. Collectively, this study demonstrates that implants have a strong and broad impact on oral mucosal homeostasis, inducing periodontal bone loss in a niche-specific manner that is both microbiota dependent and independent.

Dental implant maintenance teaching in Australia-A survey of education providers

INTRODUCTION

Implant treatments and peri-implant maintenance continue apace, while the evidence for implant maintenance and home hygiene continues to be developed. Information sources for dental practitioners and patients in peri-implant health maintenance and disease management are generally not known. This study investigated the implant maintenance topics taught, the discipline backgrounds of convenors and presenters and information delivery methods within implant dentistry teaching in Australia.

MATERIALS AND METHODS

An online survey was distributed to 56 convenors of implant dentistry and maintenance education programmes in Australia, garnering responses from 24 individuals which outlined 43 different education programmes.

RESULTS

Lectures were the main delivery method for implant maintenance information across the different course types. Peri-implant diagnostics were generally taught according to current literature recommendations, but coverage varied in topics where the evidence is yet to be established (eg home hygiene, professional maintenance and implant review). Some educators reported awareness of limitations in their programmes.

CONCLUSION

Implant dentistry education programmes in Australia vary widely in teaching implant maintenance, coverage of which should be current and evidence-based at all education levels. The structure of implant dentistry teaching at the continuing professional development level requires further development.

Emerging Applications of Drug Delivery Systems in Oral Infectious Diseases Prevention and Treatment

The oral cavity is a unique complex ecosystem colonized with huge numbers of microorganism species. Oral cavities are closely associated with oral health and sequentially with systemic health. Many factors might cause the shift of composition of oral microbiota, thus leading to the dysbiosis of oral micro-environment and oral infectious diseases. Local therapies and dental hygiene procedures are the main kinds of treatment. Currently, oral drug delivery systems (DDS) have drawn great attention, and are considered as important adjuvant therapy for oral infectious diseases. DDS are devices that could transport and release the therapeutic drugs or bioactive agents to a certain site and a certain rate in vivo. They could significantly increase the therapeutic effect and reduce the side effect compared with traditional medicine. In the review, emerging recent applications of DDS in the treatment for oral infectious diseases have been summarized, including dental caries, periodontitis, peri-implantitis and oral candidiasis. Furthermore, oral stimuli-responsive DDS, also known as "smart" DDS, have been reported recently, which could react to oral environment and provide more accurate drug delivery or release. In this article, oral smart DDS have also been reviewed. The limits have been discussed, and the research potential demonstrates good prospects.

Regrowth of Microcosm Biofilms on Titanium Surfaces After Various Antimicrobial Treatments

Objectives: Our aim of this work was to investigate the regrowth of implant-related biofilms after various antimicrobial treatments in vitro. Methods: Saliva-derived microcosm biofilms were grown on titanium discs in an active attachment model. Treatments including hydrogen peroxide (HP), citric acid (CA), chlorhexidine (CHX), and distilled water (control), at different concentrations, were applied to 2-day biofilms for 1 or 5 min. The viability, lactic acid production, and composition of the biofilms were followed for 3 days. The biofilm composition was analyzed by 16S rDNA amplicon sequencing. Results: The short treatments of CA, CHX, and HP resulted in a 2-3 log reduction in biofilm viability and lactic acid production immediately. However, both parameters returned to the pre-treatment level within 2 days due to biofilm regrowth. The alpha diversity of the regrown biofilms in antimicrobial-treated groups tended to decrease, whereas the diversity of those in water-treated group increased. The composition of the regrown biofilms altered compared to those before treatments. Streptococcus and Enterobacteriaceae were enriched in the regrown biofilms. Conclusions: Although the antimicrobial treatments were efficient, the multi-species biofilms were indeed able to regrow within 2 days. The regrown biofilms display an altered microbial diversity and composition, which in the oral cavity may lead to an aggressive infection.

Tobacco-product usage as a risk factor for dental implants

The oral cavities of tobacco smokers and users of smokeless tobacco products are exposed to high concentrations of nicotine. A limited number of animal studies have assessed the effect of nicotine on osseointegration. Results from experimental studies have reported a statistically significant decrease, at 4 weeks of follow-up, in bone-to-implant contact among rats exposed to nicotine compared with unexposed rats. Nicotine increases the production of inflammatory cytokines (such as interleukin-6 and tumor necrosis factor-alpha) by osteoblasts. Waterpipe, pipe, and cigarette smokers are at increased risk of developing oral cancer, periodontal disease, and alveolar bone loss. One explanation for this is that smokers (regardless of the type of tobacco product) are exposed to similar chemicals, such as nicotine, tar, oxidants, polyaromatic hydrocarbons, and carbon monoxide. Moreover, raised levels of proinflammatory cytokines have been identified in the gingival crevicular fluid of cigarette smokers with peri-implant diseases. Therefore, it is hypothesized that nicotine and chemicals in tobacco smoke induce a state of oxidative stress in peri-implant tissues (gingiva and alveolar bone), thereby increasing the likelihood of peri-implant disease development via an inflammatory response, which if left uncontrolled, will result in implant failure/loss. In this regard, tobacco smoking (including cigarettes, waterpipe, and pipe) is a significant risk factor for peri-implant diseases. The impact of vaping electronic cigarettes using nicotine-containing e-juices remains unknown. Habitual use of smokeless tobacco products is associated with oral inflammatory conditions, such as oral precancer, cancer, and periodontal disease. However, the effect of habitual use of smokeless tobacco products on the success and survival of dental implants remains undocumented.

Strontium Effects on Human Gingival Fibroblasts

Strontium is a naturally occurring alkaline earth metal that has been shown to be useful not only in the treatment and prevention of osteoporosis but also in the treatment of dentinal hypersensitivity in the oral cavity; strontium is also an effective cariostatic, antiplaque, antigingivitis agent. Relatively little is known, however, about the effects of strontium on gingival fibroblasts. The purpose of the present investigation was to conduct in vitro studies on the potential for strontium to positively affect the activity of these cells such that it might be effective in the enhancement of gingival attachment to surfaces, such as healing abutments in implants in the oral cavity. The results indicate that strontium added as strontium citrate (0.5–1.0 mM), both in the absence and presence of a healing abutment, increases human gingival cell activity and decreases apoptosis in these cells. Scanning electron microscopy studies also reveal that the addition of strontium increases attachment of gingival fibroblasts to the surfaces of healing abutments. These studies provide the basis for further investigations on the use of strontium in the prevention and treatment of peri-implantitis by maximizing the formation of a peri-implant soft-tissue barrier.

Antimicrobial Efficacy of Materials Used for Sealing the Implant Abutment Screw Hole: An In Vitro Evaluation

AIM

The aim of this in vitro study was to assess the antimicrobial efficacy of materials (gutta percha [GP], polytetrafluoroethylene [PTFE] tape, and vinyl polysiloxane [VP]) used for sealing the implant abutment screw hole (IASH).

METHODS

Sixty implants with a Morse cone connection were used. The implants were randomly divided into 3 groups (20 implants/group). In groups 1, 2, and 3, the IASH was sealed with GP, PTFE, and VP, respectively. Unstimulated whole saliva (UWS) was used as a contaminant medium for the incubation of the specimens. After 7 days of incubation, the specimens were opened under aseptic conditions, and the contents of the inner parts of the IASH were collected using sterile microbrushes. The occurrence of microbial leakage through the screw access channel interface was assessed with the checkerboard DNA-DNA hybridization method. P < 0.05 was considered statistically significant.

RESULTS

Among samples in groups 1, 2, and 3, the UWS collected before incubation showed no statistically significant differences in relation to the prevalence of species investigated. Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, and Candida albicans were isolated from group 1 than groups 2 and 3.

CONCLUSION

The choice of material for sealing the IASH is entirely dependent on the operators' choice and experience.

Antibacterial effect of hydrogen peroxide-titanium dioxide suspensions in the decontamination of rough titanium surfaces

The chemical decontamination of infected dental implants is essential for the successful treatment of peri-implantitis. The aim of this study was to assess the antibacterial effect of a hydrogen peroxide-titanium dioxide (H₂O₂-TiO₂) suspension against Staphylococcus epidermidis biofilms. Titanium (Ti) coins were inoculated with a bioluminescent S. epidermidis strain for 8 h and subsequently exposed to H₂O₂ with and without TiO₂ nanoparticles or chlorhexidine (CHX). Bacterial regrowth, bacterial load and viability after decontamination were analyzed by continuous luminescence monitoring, live/dead staining and scanning electron microscopy. Bacterial regrowth was delayed on surfaces treated with H₂O₂-TiO₂ compared to H₂O₂. H₂O₂-based treatments resulted in a lower bacterial load compared to CHX. Few viable bacteria were found on surfaces treated with H₂O₂ and H₂O₂-TiO₂, which contrasted with a uniform layer of dead bacteria for surfaces treated with CHX. H₂O₂-TiO₂ suspensions could therefore be considered an alternative approach in the decontamination of dental implants.

Role of mechanical curettage with and without adjunct antimicrobial photodynamic therapy in the treatment of peri-implant mucositis in cigarette smokers: A randomized controlled clinical trial

OBJECTIVE

The aim of the present 12-weeks follow-up randomized clinical trial was to investigate the outcome of mechanical curettage (MC) with or without adjunct antimicrobial photodynamic therapy (aPDT) in the treatment of peri-implant mucositis in cigarette smokers.

METHODS

Therapeutically, subjects with peri-implant mucositis were divided into 2 groups: (a) Group-A: MC+aPDT; and (b) Group-B: MC alone (control group). In both groups, peri-implant plaque index (PI), bleeding on probing (BOP) and probing pocket depth (PPD) were gauged at baseline and after 12-weeks follow-up. Group comparisons were performed using the Kruskall-Wallis test. P-values less than 0.05 were considered statistically significant.

RESULTS

Fifty-four male patients (28 in Group-A and 26 in Group-B) were included. The mean age of individuals in groups A and B were 50.6±0.8 and 52.2±0.5years, respectively. In groups A and B the participants were smoking 16.5±2.7 and 14.2±1.7 cigarettes daily since 25.2±6.5 and 24.6±4.3years, respectively. Periimplant PI, BOP and PPD were comparable among individuals in both groups at baseline. At 12-weeks follow-up, there was a significant reduction in PI (P<0.001) and PPD (P<0.001) among patients in groups A and B compared with their respective baseline values. At 12-weeks follow-up, PI (P<0.001) and PPD (P<0.001) were significantly higher among patients in Group-B compared with Group-A (P<0.001). BOP was comparable in both groups at baseline and at 12-weeks follow-up.

CONCLUSION

In cigarette smokers, MC with adjunct aPDT is more effective in the treatment of peri-implant mucositis compared with MC alone.

Efficacy of periimplant mechanical curettage with and without adjunct antimicrobial photodynamic therapy in smokeless-tobacco product users

OBJECTIVE

The aim was to investigate the effectiveness of antimicrobial photodynamic therapy (aPDT) as an adjuvant to mechanical curettage (MC) in the treatment of periimplant mucositis in smokeless tobacco (ST) product users.

METHODS

Forty-eight ST product users with periimplant mucositis were randomly divided into 2 groups. In the test-group, participants underwent periimplant MC with adjunct aPDT; and in the control-group, the patients underwent MC alone. Periimplant plaque index (PI), bleeding on probing (BOP), and probing depth (PD) were measured at baseline and after 3-months of follow-up. Statistical analysis was performed using the Kruskal-Wallis test. Level of significance was set at P<0.05.

RESULTS

At baseline, periimplant PI, BOP and PD were comparable among individuals in the test- and control groups. At 3-months follow-up, scores of periimplant PI (P<0.05), BOP (P<0.05) and PD (P<0.05) were statistically significantly higher among patients in the control-group compared with the test-group. At 3-months follow-up, the percentages of sites of PI, BOP and PD were statistically significantly higher in the control-sites as compared to the test-sites.

CONCLUSION

Among patients with periimplant mucositis, MC with adjunct aPDT is more effective in reducing periimplant inflammation in ST product users as compared to MC alone; however, the present result should be interpreted with caution as they were based on a short-term follow-up. Further long-term studies are needed in this regard.

Development of Laser-Structured Liquid-Infused Titanium with Strong Biofilm-Repellent Properties

Medical implants are commonly used in modern medicine but still harbor the risk of microbial infections caused by bacterial biofilms. As their retrospective treatment is difficult, there is a need for biomedical materials that inhibit bacterial colonization from the start without using antibacterial agents, as these can promote resistance development. The promising concept of slippery liquid-infused porous surfaces (SLIPS) possesses enormous potential for this purpose. In the present study, this principle was applied to titanium, a common material in implantology, and its biofilm-repellent properties were demonstrated. To simplify prospective approval of the medical device and to avoid chemical contamination, surface structuring was performed by ultrashort pulsed laser ablation. Four different structures (hierarchical micro- and nanosized spikes, microsized grooves, nanosized ripples, and unstructured surfaces) and five infusing perfluoropolyethers of different viscosities were screened; the best results were obtained with the biomimetic, hierarchical spike structure combined with lubricants of medium viscosities (20-60 cSt at 37 °C, 143 AZ, and GPL 104). The surfaces exhibited extremely low contact angle hysteresis, as is typical for liquid-infused materials and a reliable 100-fold reduction of human oral pathogen Streptococcus oralis biofilms. This characteristic was maintained after exposure to shear forces and gravity. The titanium SLIPS also inhibited adherence of human fibroblasts and osteoblasts. Toxicity tests supported the explanation that solely the surface's repellent properties are responsible for the vigorous prevention of the adhesion of bacteria and cells. This use of physically structured and liquid-infused titanium to avoid bioadhesion should support the prevention of bacterial implant-associated infections without the use of antibacterial agents.

Effect of Nd:YAG laser-assisted non-surgical mechanical debridement on clinical and radiographic peri-implant inflammatory parameters in patients with peri-implant disease

BACKGROUND AND AIM

The efficacy of neodymium-doped yttrium aluminium garnet (Nd:YAG) laser-assisted non-surgical mechanical debridement (MD) in the treatment of periimplant diseases remains uninvestigated. The aim was to assess the efficacy of Nd:YAG laser-assisted non-surgical MD on clinical and radiographic periimplant inflammatory parameters in patients with periimplant disease.

METHODS

Treatment wise, 63 male patients with periimplant diseases were divided into 2 groups: Group-1 (32 patients): treatment of periimplant disease using MD alone (control group); and Group-2 (n=31 patients): treatment of periimplant disease using MD with a single application of Nd:YAG laser. Peri-implant inflammatory parameters (plaque index [PI], bleeding on probing [BOP] and probing depth [PD]) were measured at baseline and at 3 and 6months' follow-up. Periimplant crestal bone loss (CBL) was measured at baseline and at 6months' follow-up. Statistical analysis was performed using the Kruskall-Wallis and Bonferroni Post hoc tests. P-values<0.05 were considered statistically significant.

RESULTS

In both groups, mean age of patients and baseline scores of periimplant PI, BOP and PD were comparable. At 3-month follow-up, scores of periimplant PI, BOP and PD were higher among patients in Group-1 compared with Group-2. At 6-month follow-up, scores of periimplant PI, BOP and PD were comparable among patients in groups 1 and 2. There was no statistically significant difference in periimplant CBL in both groups at all time intervals.

CONCLUSION

Nd:YAG laser-assisted non-surgical MD is more effective in reducing periimplant soft tissue inflammatory parameters than MD alone in short-term but not in long-term.

Quantifying implant-associated biofilms: Comparison of microscopic, microbiologic and biochemical methods

Biofilm-associated infections pose severe problems in modern implant medicine. Screening for new implant materials with antibacterial properties requires reliable quantification of colonizing bacteria. There are many different methods to quantify biofilms on solid surfaces in vitro, employing different (bio-)chemical/microbiological reference parameters. It is therefore difficult to compare studies with different quantification techniques. Here, we have evaluated commonly used microscopic, microbiologic and biochemical methods to quantify bacterial biofilms, in order to clarify their comparability and applicability. Two bacterial species frequently involved in biofilm-associated infections, Staphylococcus aureus and Aggregatibacter actinomycetemcomitans, were used as model organisms; their initial adhesion and biofilm formation on titanium and on antibacterial copper were analyzed using the following methods: LIVE/DEAD fluorescence staining and confocal laser-scanning microscopy, ultrasonic or a newly developed enzymatic detachment followed by standard plate counting (CFU method), a resazurin-based assay, the BacTiter-Glo™ assay and crystal violet staining. The methods differed greatly in complexity, reliability and the applicability to initial adhesion and biofilm formation. To screen biofilm formation on a multitude of surfaces, the resazurin-based and the BacTiterGlo™ assay are well suited. LIVE/DEAD staining and confocal laser-scanning microscopy can be applied for a more detailed analysis of both, initial adhesion and biofilm formation. When using the CFU method for screening purposes, the introduced enzymatic detachment procedure is to be favored over ultrasonic detachment. There is not one single method, which is suitable for all purposes. The appropriate biofilm quantification method has to be chosen on the basis of the specific scientific question.

Evaluation of Temperature and Roughness Alteration of Diode Laser Irradiation of Zirconia and Titanium for Peri-Implantitis Treatment

OBJECTIVE

This study investigated the effects of diode laser (gallium, aluminium, arsenide [GaAlAs]) irradiation with decontamination parameters on the temperature and roughness of yttrium-stabilized tetragonal zirconia polycrystal (Y-TZP), titanium (TI), and sandblasted large grit acid-etched titanium (SLA).

MATERIALS AND METHODS

Three groups (n = 10) of standardized disks with 5 mm diameter and 2 mm thickness were produced with Y-TZP obtained from computer-aided design and computer-aided manufacturing (CAD-CAM), machined TI and SLA. The diode laser single application (808 nm, 20 sec, 1 W, 50 Hz, t on = 100 ms, t off = 100 ms, energy density = 28.29 J/cm(2)) was performed in contact mode, on each disk. The temperature was measured by a thermosensor attached to a digital thermometer fixed to the opposite irradiated surface. The temperature gradient (ΔT) was calculated (ΔT = final temperature - initial temperature) for each group. The parameters Ra (in μm) and Sa (in μm(2)) were measured by white light confocal laser microscopy to express the surface roughness. Data of ΔT was statistically analyzed by one way ANOVA at the 95% confidence level and compared by Tukey post-hoc test (α = 0.05). Roughness data was analyzed by t test.

RESULTS

The diode laser irradiation presented the following results (ΔT value): Y-TZP = 10.3°C(B); TI = 38.6°C(A), and SLA = 26.7°C(A). The ΔT values ((°)C) of the titanium groups were higher than for the Y-TZP group. For both roughness parameters (Ra and Sa), data did not show statistical significant differences to "irradiation" factor (p > 0.05) to Y-TZP and SLA. The Ra results (in μm) were: Y-TZP (control) = 0.73 (0.55); Y-TZP (irradiated) = 0.45 (0.27); SLA (control) = 0.74 (0.23); and SLA (irradiated) = 0.99 (0.33). The Sa results (in μm(2)) were: Y-TZP (control) = 1.39 (1.05); Y-TZP (irradiated) = 0.73 (0.41); SLA (control) = 0.85 (0.08); and SLA (irradiated) = 1.27 (0.44).

CONCLUSIONS

Diode laser irradiation for peri-implantitis treatment increased both zirconia and TI temperature without surface roughness alterations.

Current concepts in the use of lasers in periodontal and implant dentistry

Lasers have various periodontal applications including calculus removal (Er: YAG, Er, Cr: YSGG lasers); soft tissue excision, incision and ablation; decontamination of root and implant surfaces; biostimulation; bacteria reduction; and osseous surgery. This paper reviews some of the major opportunities for using lasers in periodontal and implant specialty practices. The literature relating to the use of lasers for removal of the pocket epithelium, root conditioning, bacterial reduction and decontamination of infected implant surfaces is discussed, and a summary of the advantages and disadvantages of using lasers for periodontal treatment is provided.