Preparation of an injectable zinc-containing hydrogel with double dynamic bond and its potential application in the treatment of periodontitis

Periodontal tissue regeneration continues to face significant clinical challenges. Periodontitis leads to alveolar bone resorption and even tooth loss due to persistent microbial infection and persistent inflammatory response. As a promising topical drug delivery system, the application of hydrogels in the controlled release of periodontal bioactive drugs has aroused great interest. Therefore, the design and preparation of an injectable hydrogel with self-repairing properties for periodontitis treatment is still in great demand. In this study, polysaccharide-based self-healing hydrogels with antimicrobial osteogenic properties were developed. Zinc ions are introduced into a dynamic cross-linking network formed by dynamic Schiff bases between carboxymethyl chitosan and oxidized hyaluronic acid via coordination bonds. The OC-Zn hydrogels exhibited good tissue adhesion, good fatigue resistance, excellent self-healing ability, low cytotoxicity, good broad-spectrum antimicrobial activity, and osteogenic activity. Therefore, the designed hydrogels allow the development of drug delivery systems as a potential treatment for periodontitis.

Impact of dental health intervention on cardiovascular metabolic risk: a pilot study of Japanese adults

This study aimed to determine whether a dental health education program would reduce cardiometabolic risk (obesity, hypertension, dyslipidemia, and hyperglycemia) in people with periodontitis. We used annual check-up data provided by the Japanese company's health insurance union. Of 182 male employees with cardiometabolic risk and periodontal pockets at baseline, 21 participants of the dental health education program and 21 non-participants matched for age, the presence of obesity, and periodontal pocket at baseline were allocated to the intervention (mean age, 53.3 ± 7.0) and the non-intervention groups (mean age, 52.9 ± 7.0), respectively. The program focused on self-removal of dental plaque with a toothbrush and interdental brush and comprised five sessions over 12 months. In the intervention group, waist circumference (cm) and diastolic blood pressure (mmHg) decreased from 88.4 ± 6.3 to 86.8 ± 6.3 and from 85.7 ± 8.2 to 82.6 ± 8.3, respectively (P < 0.05). Intergroup comparison showed significant improvement of systolic blood pressure (mmHg) in the intervention group (-3.7 ± 12.5) compared with the non-intervention group (4.0 ± 15.9) (P < 0.05) with no significant differences in the other parameters. The intervention group had a decrease in plaque accumulation and periodontitis symptoms, such as the depth of periodontal pocket and the presence of periodontal pocket and bleeding on probing, but an increase in the frequency of interdental brushing and duration of tooth brushing. Our findings show that dental self-care may improve blood pressure in people with cardiometabolic risk factors and periodontitis.

Self-determined use of provided powered oral hygiene devices leads to improved gingival health after 1 year: a longitudinal clinical trial

PURPOSE

Our study aimed to evaluate the long-term concordance and acceptance when using powered devices for everyday oral hygiene routine and gingival health in patients showing papillary bleeding.

PATIENTS AND METHODS

Thirty-one participants were recruited at the dental clinic of the University Hospital of Cologne, Germany, over a 6-week duration. At baseline, a standard dental check-up was performed, including oral hygiene indices and documentation of oral hygiene devices used. The study consisted of two consecutive phases: the first (motivational trial) was designed to prove the effectiveness and safety of a microdroplet device and a powered toothbrush compared to dental floss and a manual toothbrush over a period of 4 weeks. The second (observational) phase began with all participants receiving the powered oral homecare devices. Participants were able to use their oral hygiene measures of choice over an unsupervised period of 1 year. All participants were then rescheduled for a routine dental check-up, where oral hygiene indices and oral hygiene devices used were reevaluated.

RESULTS

After 1 year, 93.3% of participants stated they performed interdental cleaning on a regular basis (baseline 60.0%). The percentage using a powered toothbrush increased from 41.9% (baseline) to 90.0% after 1 year. Oral hygiene parameters had improved after both the motivational trial and observational phases compared to baseline (papillary bleeding index p = .000; Rustogi Modified Navy Plaque Index p < .05; Quigley-Hein Index p = .000).

CONCLUSION

In the long term, participants preferred using powered oral hygiene devices over the gold standard dental floss and manual toothbrush. Improved oral hygiene parameters after 1 year may indicate implementation of newly acquired oral-hygiene skills during the 4-week instruction phase.

Impact of manual toothbrush design on plaque removal efficacy

BACKGROUND

Effective dental plaque removal is essential for oral health. Different toothbrush parameters including head-size, filament-diameter and interdent-height and different brushing movements like horizontal, rotating and vertical may affect plaque removal efficacy. The purpose of the study was to examine plaque removal efficacy of different design parameters of manual toothbrushes.

METHODS

Eight manual toothbrushes were tested using a validated robot test to examine efficacy of toothbrush on replicated human teeth. Characteristics tested were: (i) head-size, (ii) filament-diameter, (iii) cutting-height, (iv) hardness, (v) interdental-height. Each test ran five times in horizontal, rotating, vertical movements. Simulated Plaque removal was evaluated using automated plaque planimetry: 30 fields/tooth, 13 areas representing buccal, lingual, proximal tooth sites. The Kolmogorov-Smirnov-test was applied to test tooth surface variables for normal distribution of plaque removal values. Parameters were analysed by independent two-sample t-test to assess mean differences. Where null hypothesis of normality was rejected, the Wilcoxon-Mann-Whitney-U-test was used.

RESULTS

Plaque removal was significantly better with toothbrush having smaller head-size (compact vs. full-size); smaller filament-diameter (0.12 mm vs. 0.15 mm); larger cutting-height (12 mm vs. 9 mm); softer filaments (0.15 or 0.18 mm vs. 0.23 mm) and greater interdent-height difference (8.5/11 mm vs. 10/11 mm).

CONCLUSIONS

Manual brushes allowing filaments free to flex with longer, softer and/or having a difference in filament length overall removed significantly more simulated plaque as compared to more standard flat trim, stiff brushes with shorter, harder bristles and a larger head size. While limited by the in vitro nature of the study design, this indicates that the advances in toothbrush design can further enhance plaque removal.

Plaque removal by a novel prototype power toothbrush versus a manual toothbrush: A randomized, exploratory clinical study

OBJECTIVES

This exploratory study investigated plaque removal with a prototype constant, low rotation speed Power Toothbrush (PTB) with two brushing actions: "Gumline" (head rotates in the horizontal axis) and "Interdental" (head rotates in the vertical axis). Gumline alone and "Combined" (Gumline + Interdental) modes were compared with a Reference PTB and a Reference Manual Toothbrush (MTB) after one brushing.

MATERIALS AND METHODS

Thirty-nine participants were randomized to use each toothbrush once either in the sequence (A) Prototype PTB (in Gumline then Combined mode), (B) reference MTB, and (C) reference PTB or the sequence BAC. There was a minimum 3-day washout between the use of each toothbrush. Plaque removal was measured using the Rustogi Modified Navy Dental Plaque Index (RMNPI) with change from baseline investigated using an analysis of covariance model. RMNPI scores were calculated on a "whole mouth" basis and along the gingival margin and at proximal sites only.

RESULTS

For the primary efficacy variable, a significant difference was found in favor of the prototype PTB in gumline mode versus the reference MTB for whole mouth plaque score (difference: -0.06; standard error: 0.014; 95% confidence interval [CI] -0.09 to -0.04; p < .0001). Similar significant differences were found in gingival margin and proximal areas (p < .0001). The prototype PTB in gumline mode removed significantly less plaque than the prototype PTB in combined mode and the reference PTB (p < .0001; whole mouth/gingival/proximal areas). The prototype PTB in combined mode removed significantly more plaque than the reference MTB (p < .0001; whole mouth/gingival/proximal areas) and the reference PTB for whole mouth (p = .0214) and gingival margin areas (p = .0010). The reference PTB also removed significantly more plaque than the reference MTB (p < .0001; whole mouth/gingival/proximal areas). All brushes were generally well-tolerated.

CONCLUSION

The prototype PTB design, providing two distinct cleaning modalities, can effectively remove plaque to a significantly higher degree than an MTB and a marketed PTB, depending on mode.

Are oral hygiene instructions with aid of plaque-disclosing methods effective in improving self-performed dental plaque control? A systematic review of randomized controlled trials

OBJECTIVES

To systematically evaluate the literature on whether plaque-disclosing (PD) methods, applied by dental professionals (FQ1) or at-home (FQ2), combined with verbal oral hygiene instructions and brushing demonstration (standard OHI) lead to improvements in self-performed dental plaque control in comparison to standard OHI alone.

MATERIALS AND METHODS

Seven databases were searched by two independent reviewers according to pre-specified eligibility criteria up to September 2020. No restrictions regarding language, date and type of report were imposed. The Cochrane Collaboration's Risk of Bias tool (RoB 2.0) was used for quality appraisal. Multiple comparisons referring to a single study were included if the articles evaluated different PD agents. Narrative synthesis using evidence tables were performed.

RESULTS

Seven eligible studies were retrieved, including data of 430 individuals (159 wearers of orthodontic appliances). The studies exhibited considerable heterogeneity regarding outcome assessments and follow-up. Eleven (eight corresponding to FQ1 and three to FQ2) out of 13 relevant comparisons found no significant difference between techniques for dental plaque outcomes and three (two corresponding to FQ1 and one to FQ2) out of five comparisons indicated a positive effect of standard OHI with aid of PD methods on gingival inflammation scores. With respect specifically to orthodontic patients, three out of four comparisons indicated significant improvements on gingival inflammation scores for individuals instructed with PD methods.

CONCLUSION

Clinicians should consider PD agents as adjunct to standard OHI in orthodontic patients. For those without appliances, PD methods can be used as an alternative.

Effects of Chlorine Dioxide on Oral Hygiene - A Systematic Review and Meta-analysis

Background

Effective and selective oral rinses are required in the daily medical and dental practice. Currently mouthwashes used have substantial side effects.

Objectives

Our aim was to evaluate the efficacy of chlorine dioxide-containing mouthwashes in comparison with other previously established mouth rinses in healthy adults using oral hygiene indices.

Methods

This work was registered in PROSPERO (CRD42018099059) and carried out using multiple databases and reported according to the PRISMA statement. The search terms used were “chlorine dioxide” AND “oral”, and only randomised controlled trials (RCTs) were included. The primary outcome was the alteration of the plaque index (PI), while the secondary outcomes were the gingival index (GI) and bacterial counts. For the risk of bias assessment, the Cochrane Risk of Bias Tool was used. Statistical analysis for data heterogeneity was performed by Q-value and I²-tests.

Results

364 articles were found in the databases. After the selection process, only five RCTs were eligible for meta-analysis. Data heterogeneity was low. There were no statistical differences in effectiveness between chlorine dioxide and other effective mouth rinses in PI (0.720±0.119 vs 0.745±0.131; 95%; confidence intervals (CIs): 0.487-0.952 vs 0.489-1.001, respectively) and GI (0.712±0.130 vs 0.745±0.131; 95% CIs: 0.457–0.967 vs 0.489–1.001, respectively) and also in bacterial counts.

Conclusion

Chlorine dioxide reduces both plaque and gingival indices and bacterial counts in the oral cavity similar to other routinely used oral rinses, however, the evidence supporting this outcome is very limited. Therefore, further large scale RCTs are needed to decrease the risk of bias.

Evaluating Cognitive/Emotional and Behavioral Mediators of Oral Health Outcomes in Vulnerable Older Adults

Inconsistent outcomes of oral hygiene interventions require testable theories combining cognitive and behavioral domains to guide intervention and improve results. This article evaluates the integrated model as a cognitive-behavioral approach to improve oral health clinical outcomes in ethnically diverse low-income older adults. Baseline data from a clinical trial utilizing the integrative model (IM) model evaluated predictors of gingival index (GI) and plaque score (PS). Individual logistic regression was performed for all predictors in relation to GI and PS. Multiple logistic regression was performed with significant predictors of GI and PS only. Greater locus of control and more brushing predicted lower GI; greater locus of control predicted lower PS. Both cognitive and behavioral domains impact GI, requiring more prolonged effort for improvement while locus of control, a cognitive variable, predicts PS, immediately improved by daily brushing/flossing. A streamlined IM including locus of control and tooth brushing should improve oral hygiene of low-income older adults.

Changing the Focus to the Whole Patient instead of One Oral Disease: The Concept of Individualized Prevention

Oral diseases are highly prevalent and a global burden. Accordingly, their prevention appears essential. Recently, different strategies have been developed, mainly focusing on the presence of singular oral diseases or conditions. This article aims to construct a contemporary concept of individualized preventive care in dentistry whereby the focus is switched from viewing oral health in isolation to viewing the patient as a whole. The basis for individualized prevention measures is the case-oriented profile, including the synthesis of risk- and need-oriented parameters. The risk profile comprises different risk factors within the fields of systemic diseases, medications, and lifestyle that inherently pose a potential risk of complications (e.g., infectious endocarditis) and/or oral diseases (e.g., periodontitis). The needs profile includes factors originating from the aspects of oral diseases, dental restorations/appliances, and dental results with a potential risk of pathogenesis (e.g., the de novo development of caries) and/or the potential progression of oral diseases (e.g., an existing caries lesion). Based on these parameters, the general framework and content of prevention measures, as well as the maintenance interval, should be adapted to the individual patient. The implications of this concept might increase the safety, effectiveness, and efficiency of prevention in dental care. A further area of focus is primary prevention, that is, a focus on the preservation of oral health instead of a disease-related approach. However, clinical validation is needed to prove the benefits of the model presented. Individualized prevention promotes a shift from a disease-focused model to a whole-patient-focused model and provides a potential approach for establishing a contemporary concept for preventive care in dentistry.

Adverse events associated with home use of mouthrinses: a systematic review

Background

Poor oral hygiene is strongly associated with oral and systemic diseases. Alongside mechanical tooth cleaning, the adjunctive use of mouthrinses has been widely advocated. Although research on the efficacy of various mouthrinse formulations is very active, there are a lack of conclusive data regarding their adverse effects.

Methods

We undertook a systematic review in accordance wih PRISMA guidelines of electronic databases of clinical trials of any duration with daily home use of mouthwashes, presenting clinical and subjective side effects (PROSPERO registration: CRD42016054037).

Results

After evaluating 614 titles and abstracts, 154 studies were selected for full-text analysis; 85 final papers were included. Based on the active ingredient in the test product, nine categories were created: cetyl pyridinium chloride, essential oils, chlorhexidine, triclosan, natural products, diclofenac, fluorides, delmopinol, and miscellaneous active substances. Most of the studies were of short duration (less than 6 months) with a defective 'methods' description; the reporting of adverse events often being overlooked. Both local morphological (oral mucosa and dental-crown staining, mucosal lesions) and functional (taste modifications, abnormal oral sensation) alterations were reported. Tooth staining was the most commonly listed adverse event, but it was quantitatively assessed only in a very small number of papers; most studies relied on patient reports. Staining was time associated; the longer the study, the higher its reported incidence and severity.

Conclusions

The reduced report of side effects may partly be due to a lack of an objective measure and lack of general guidelines that demand studies report their adverse events. The most frequently reported adverse effect was teeth staining. As in most studies, the effect was associated with trial duration; clinical trials should be of sufficient duration. New investigations meeting the suggested criteria of a minimal duration of 6 months should be planned.

No differences in microbiome changes between anti-adhesive and antibacterial ingredients in toothpastes during periodontal therapy

Aim

This subgroup analysis of a 12‐week randomized, double‐blind, and two‐center trial aimed to evaluate whether two different toothpaste formulations can differentially modulate the dental microbiome.

Material and Methods

Forty one mild to moderate periodontitis patients used as an adjunct to periodontal treatment either a toothpaste with anti‐adhesive zinc‐substituted carbonated hydroxyapatite (HA) or with antimicrobial and anti‐adhesive amine fluoride/stannous fluoride (AmF/SnF₂) during a 12‐week period. Plaque samples from buccal/lingual, interproximal, and subgingival sites were taken at baseline, 4 weeks after oral hygiene phase, and 8 weeks after periodontal therapy. Samples were analyzed with paired‐end Illumina Miseq 16S rDNA sequencing. The differences and changes on community level (alpha and beta diversity) and on the level of single agglomerated ribosomal sequence variants (aRSV) were calculated with analysis of covariance (ANCOVA) and likelihood ratio test (LRT).

Results

Interproximal and subgingival sites harbored predominately Fusobacterium and Prevotella species associated with periodontitis, whereas buccal/lingual sites harbored mainly Streptococcus and Veillonella species associated with periodontal health. Alpha and beta diversity did not change noticeably differently between both toothpaste groups (P > 0.05, ANCOVA). Furthermore, none of the aRSVs showed a noticeably different change between the tested toothpastes during periodontal therapy (P_adj .> 0.05, LRT).

Conclusion

The use of a toothpaste containing anti‐adhesive HA did not induce statistically noticeably different changes on microbial composition compared to an antimicrobial and anti‐adhesive AmF/SnF₂ formulation.

Evaluation of Antibacterial Effect of Propolis and its Application in Mouthwash Production

Objectives:

Our purpose was to determine the antibacterial properties of propolis and to evaluate its use as an antibacterial mouthwash with minimal complications.

Materials and Methods:

In this experimental laboratory study, an alcoholic propolis extract was prepared. The minimum inhibitory concentration (MIC) was calculated for four bacterial species including Staphylococcus aureus (S. aureus), Streptococcus mutans (S. mutans), Lactobacillus acidophilus (L. acidophilus), and Enterococcus faecalis (E. faecalis) using agar dilution. According to the MIC, a propolis antibacterial mouthwash was produced and compared to water, chlorhexidine (CHX), and Listerine using laboratory rats for clinical examination. Salivary specimens of rats were collected at 12 hours, 1 week, and 2 weeks after using the mouthwash and examined by real-time polymerase chain reaction (RT-PCR). Data were analyzed using one-way analysis of variance (ANOVA) and repeated measures ANOVA (α=0.05).

Results:

The results of agar dilution by the number of colony-forming units showed the lowest MIC for S. aureus and the highest for L. acidophilus. Our RT-PCR findings indicated that water alone had no effect on the level of oral bacteria. Propolis mouthwash showed a significant difference with CHX and Listerine (P<0.05) in terms of the number of S. mutans, E. faecalis, and L. acidophilus colonies, while CHX and Listerine were less efficient. There was no significant difference between CHX and propolis (P=0.110) regarding S. aureus colonies, but Listerine had a lower efficacy than either (P<0.05).

Conclusion:

According to the results, propolis mouthwash was more efficient against the studied oral bacteria compared to CHX and Listerine.

Evidence-Based Update on Diagnosis and Management of Gingivitis and Periodontitis

This article is an overview to update the practicing general dental practitioner about clinically relevant evidence-based topics published in the recent past in the diagnosis, etiopathogenesis, and management of gingivitis and periodontitis.

Periodontitis: facts, fallacies and the future

This volume of Periodontology 2000 represents the 25th anniversary of the Journal, and uses the occasion to assess important advancements in periodontology over the past quarter-century as well as the hurdles that remain. Periodontitis is defined by pathologic loss of the periodontal ligament and alveolar bone. The disease involves complex dynamic interactions among active herpesviruses, specific bacterial pathogens and destructive immune responses. Periodontal diagnostics is currently based on clinical rather than etiologic criteria, and provides limited therapeutic guidance. Periodontal causative treatment consists of scaling, antiseptic rinses and occasionally systemic antibiotics, and surgical intervention has been de-emphasized, except perhaps for the most advanced types of periodontitis. Plastic surgical therapy includes soft-tissue grafting to cover exposed root surfaces and bone grafting to provide support for implants. Dental implants are used to replace severely diseased or missing teeth, but implant overuse is of concern. The utility of laser treatment for periodontitis remains unresolved. Host modulation and risk-factor modification therapies may benefit select patient groups. Patient self-care is a critical part of periodontal health care, and twice-weekly oral rinsing with 0.10-0.25% sodium hypochlorite constitutes a valuable adjunct to conventional anti-plaque and anti-gingivitis treatments. A link between periodontal herpesviruses and systemic diseases is a strong biological plausibility. In summary, research during the past 25 years has significantly changed our concepts of periodontitis pathobiology and has produced more-effective and less-costly therapeutic options.

Microbiological and clinical effects of an oral hygiene regimen

Objective

This study compared the additional effect of rinsing with a fluoride-free and alcohol-free 0.075% cetylpyridinium chloride (CPC) mouthwash to brushing alone on dental plaque, gingival inflammation, and supragingival plaque bacteria.

Methods

Adult subjects [n = 68] completed a washout period prior to baseline evaluations that evaluated gingival inflammation, gingival bleeding, dental plaque, and pocket probing depths along with microbiological analysis of supragingival plaque for bacteria. Subjects were randomized to two treatment groups: brush with fluoride toothpaste and rinse with the CPC mouthwash (test) or brush with fluoride toothpaste only (control), twice daily for the next four weeks. Subjects abstained from oral hygiene for twelve-hours prior to two-week and four-week post-treatment microbiological analysis of supragingival plaque for bacteria. Clinical assessments for gingival inflammation, gingival bleeding, dental plaque, and pocket probing depths were conducted at the four-week post-treatment visit.

Results

Compared to baseline, bacteria of dental plaque in the test group were reduced by 61.1% and 83.0% at the two-week and four-week evaluations, respectively (p < 0.05). Compared to baseline, bacteria of supragingival plaque in the control group were reduced by 2.3% at either post-treatment evaluations (p < 0.05). Additionally, dental plaque bacteria in the test was 69.8% and 86.8% lower than the control at the two-week and four-week evaluations (p < 0.05), respectively. After four-weeks, the test group showed 14.3% less gingivitis, 11.2% less dental plaque, 7.5% less gingival bleeding compared to the control group (p < 0.05).

Conclusions

Oral hygiene comprising toothbrushing and rinsing with a mouthwash containing 0.075% cetylpyridinium chloride demonstrated greater reductions of dental plaque bacteria, improving gingival health, and eliminating supragingival plaque than toothbrushing alone.

Effectiveness of flossing loops in the control of the gingival health

Background

One of the key factor in the good condition of periodontal tissues is their daily hygiene. Oral hygiene techniques such brushing and a good interdental hygiene by correct flossing are very important. The aim of this study is to compare the use of dental floss in a loop vs traditional floss in the control of Loe-Silness Gingival Index (IG), Turesky´s Plaque Index (IPT), Gingival Bleeding Index (IS) and the values of interleukin 6 (IL-6) and interleukin 8 (IL-8).

Material and Methods

A comparative study of 40 patients in which each patient was his own control, using during 45 days each one of the devices (new loop floss and conventional floss) of interdental hygiene analysed. Data for Loe-Silness Gingival Index (IG), Turesky´s Plaque Index (IPT), Gingival Bleeding Index (IS) and the values of interleukin 6 (IL-6) and interleukin 8 (IL-8)were collected and measured in every visit for every type of interdental hygiene device.

Results

Our data indicates that the rate of Turesky´s Plaque Index presented statistically significant differences between groups (loop: 1.66 ± 0.8; traditional: 1.12 ± 0.8; p<0.0001). The rest of the indices studied showed no statistically significant differences.

Conclusions

The creation of new dental floss designs try to make their use easier and more sensitive, and plaque removal more effective. The loop design can facilitate interdental hygiene, reaching similar effectiveness than traditional floss, improving some indicators, such as Turesky´s Plaque Index.

Key words:Dental floss, bacterial plaque, loop floss, plaque index, periodontal diseases.

Mouthwashes in the 21st century: a narrative review about active molecules and effectiveness on the periodontal outcomes

INTRODUCTION

Poor oral hygiene is a major risk factor for oral diseases. Regular home-based care is essential to maintain good oral hygiene. In particular, mouthrinses can support conventional tooth brushing in reducing accumulation of oral plaque. Areas covered: The most common molecules contained in mouthrinses (chlorhexidine, essential oils, cetyl pyridinium chloride, triclosan, octeneidine, delmopinol, polyvinylpyrrolidone, hyaluronic acid, natural compounds) are discussed, together with relevant clinical and in vitro studies, focusing on their effects on periodontal health. Currently, chlorhexidine is the most efficacious compound, with both antiplaque and antibacterial activities. Similar results are reported for essential oils and cetyl pyridinium chloride, although with a somewhat reduced efficacy. Considering the adverse effects of chlorhexidine and its time-related characteristics, this molecule may best be indicated for acute/short-term use, while essential oils and cetyl pyridinium chloride may be appropriate for long-term, maintenance treatment. Expert opinion: The literature has not clearly demonstrated which compound is the best for mouthrinses that combine good efficacy and acceptable side effects. Research should focus on substances with progressive antibacterial activity, prompting a gradual change in the composition of oral biofilm and mouthrinses that combine two or more molecules acting synergistically in the mouth.

Minimally invasive periodontal therapy for general practitioners

There remains a high prevalence of mild-to-moderate forms of periodontal diseases in both developed and developing countries. Although many periodontal specialty practices currently place strong emphasis on implant surgery, periodontal plastic surgery and esthetics, general dentists and hygienists have often assumed more responsibility than periodontal specialty practices for the diagnosis, treatment, assessment and maintenance, and possible referral, of their patients. To address these current trends and challenges, this volume of Periodontology 2000 presents a series of topics on the basic biological principles of periodontal disease, as well as on approaches to diagnosis, treatment planning and treatment, in what is called 'conservative' or 'noninvasive' periodontal therapy. These topics include risk assessment of the periodontal condition; reduction, elimination and/or control of etiologies and risk factors, including mechanical, antimicrobial and host-modulation approaches; considerations for evaluation of clinical outcomes based on treatment approaches; and selected topics in laser therapy, halitosis and gingival recession.