Lasers and the treatment of periodontitis: the essence and the noise.

The dental literature contains 25 years of accumulated reports and clinical studies addressing the utility of lasers in the treatment of periodontitis, both as a monotherapy or as an adjunct to surgical and nonsurgical therapy. Yet, the evidence from the 118 human clinical studies cited in this narrative review remains conflicted and insufficient to suggest that integration of a laser in a periodontal treatment protocol will provide antimicrobial and healing outcomes superior to those achieved by traditional therapy. When viewed as a collective body of evidence, it becomes apparent that a majority of the studies are underpowered and exhibit significant heterogeneity in design. Furthermore, the collected studies report a varied choice of parameters, even within the same wavelength of laser. There is little uniformity between studies in the reporting of measured clinical parameters. Most studies reported 3- and/or 6-month post-treatment results; however, the range of time intervals includes studies reporting results from 1 week to up to 1-12 months or longer. Lastly, many studies were considered at risk for bias as a result of a lack of examiner masking and/or calibration. There is great need for well-designed, highly controlled multicenter clinical trials that are adequately powered in terms of subject enrollment, that use similar protocols in terms of laser parameters and that report measureable outcomes in a uniform manner. Without such studies, the questions surrounding the use of lasers in the treatment of periodontal disease will persist.

Structural arrangement of the intracellular Ca2+ binding domains of the cardiac Na+/Ca2+ exchanger (NCX1.1): effects of Ca2+ binding.

The cardiac Na(+)/Ca(2+) exchanger (NCX1.1) serves as the primary means of Ca(2+) extrusion across the plasma membrane of cardiomyocytes after the rise in intracellular Ca(2+) during contraction. The exchanger is regulated by binding of Ca(2+) to its intracellular domain, which contains two structurally homologous Ca(2+) binding domains denoted as CBD1 and CBD2. NMR and x-ray crystallographic studies have provided structures for the isolated CBD1 and CBD2 domains and have shown how Ca(2+) binding affects their structures and motional dynamics. However, structural information on the entire Ca(2+) binding domain, denoted CBD12, and how binding of Ca(2+) alters its structure and dynamics is more limited. Site-directed spin labeling has been employed in this work to address these questions. Electron paramagnetic resonance measurements on singly labeled constructs of CBD12 have identified the regions that undergo changes in dynamics as a result of Ca(2+) binding. Double electron-electron resonance (DEER) measurements on doubly labeled constructs of CBD12 have shown that the ß-sandwich regions of the CBD1 and CBD2 domains are largely insensitive to Ca(2+) binding and that these two domains are widely separated at their N and C termini. Interdomain distances measured by DEER have been employed to construct structural models for CBD12 in the presence and absence of Ca(2+). These models show that there is not a major change in the relative orientation of the two Ca(2+) binding domains as a result of Ca(2+) binding in the NCX1.1 isoform. Additional measurements have shown that there are significant changes in the dynamics of the F-G loop region of CBD2 that merit further characterization with regard to their possible involvement in regulation of NCX1.1 activity.

The effect of the thermal diode laser (wavelength 808-980 nm) in non-surgical periodontal therapy: a systematic review and meta-analysis.

FOCUSED QUESTION: What is the adjunctive effect of a diode laser (DL) following non-surgical periodontal debridement (SRP) during the initial phase of periodontal therapy on the clinical parameters of periodontal inflammation. MATERIAL AND METHODS: The MEDLINE-PubMed, Cochrane-Central Register of Controlled Trials and EMBASE databases were searched up to September 2013. Probing pocket depth (PPD) and clinical attachment loss (CAL) were selected as outcome variables. Also plaque scores (PS), bleeding scores (BS) and the Gingival Index (GI) were considered outcome measures. Data were extracted and a meta-analysis (MA) was performed where appropriate. RESULTS: Independent screening of 416 unique papers resulted in nine eligible publications. The MA evaluating PPD, CAL and PS showed no significant effect. The only significance favouring adjunctive use of the DL was observed for the outcome parameters GI and BS. CONCLUSION: The collective evidence regarding adjunctive use of the DL with SRP indicates that the combined treatment provides an effect comparable to that of SRP alone. That is for PPD and CAL. The body of evidence considering the adjunctive use of the DL is judged to be "moderate" for changes in PPD and CAL. With respect to BS, the results showed a small but significant effect favouring the DL, however, the clinical relevance of this difference remains a question. This systematic review questions the adjunctive use of DL with traditional mechanical modalities of periodontal therapy in patients with periodontitis.

Academic dentistry in the 21st century: professional dental education or development of a trade guild.

Over the last decade, 10 new dental schools have been established and several more are on the drawing board for the near future. The overlying philosophy for this new generation of dental school is driven by a combination of societal and financial issues. As with many profound changes in educational philosophy, sooner or later there are always the unintended consequences that must be confronted. This article addresses several of the potential consequences.

Laser and scanning electron microscopy evaluation of residual microislands of calculus.

BACKGROUND: Recent studies suggest a role for microscopic crystalline particles of residual dental calculus in the pathogenesis of periodontitis. The purpose of this ex vivo study was to compare the effectiveness of scaling and root planing (SRP) alone versus SRP combined with 24% ethylenediamine-tetra acetic acid (EDTA) gel in removing calculus from extracted teeth and to determine the optimal length of time for application of the EDTA. METHODS: Specimens consisted of 32 extracted teeth with heavy root calculus. A 4-mm diameter site was prepared on the root surface of each tooth which then underwent SRP. EDTA was applied to four timed groups: 30 s; 60 s; 120 s; and 180 s. Photomicrographs were taken at 40× magnification using white light (WL) and laser fluorescence (LF). Photomicrographs were analyzed using ImageJ. Specimens were also evaluated with scanning electron microscopy (SEM). RESULTS: The mean area of residual calculus after SRP was 45%-53% (45.6% ± 19.6% WL, 53.8% ± 19.7% LF). Burnishing with EDTA for one minute following SRP reduced calculus to only 14%-18% (13.9% ± 12.5% LF, 18.2% ± 11.1% WL). Use of EDTA for greater than 1 min showed no further calculus removal. SEM revealed the surface of remaining calculus was altered by burnishing with EDTA. CONCLUSION: SRP alone or SRP + 24% EDTA gel failed to remove all calculus. SRP alone removed >60% of calculus from root surfaces. Adjunctive use of 24% EDTA gel burnished on the root surface removed most of the calculus residual after SRP. Calculus remaining after EDTA burnishing exhibited a significantly altered morphologic appearance.

Perigraftitis and implant therapy: A case report.

BACKGROUND: A previous case study reported periimplantitis and concomitant perigraftitis of a second implant placed at a site that had alveolar ridge preservation three decades earlier. Infection at the site persisted 4 months after implant removal by flapless implant reversal. A flap was subsequently reflected, the grafted bone was removed, and a second alveolar ridge preservation was performed with a freeze-dried bone allograft. The publication reported infection resolved, and the site healed uneventfully. However, it is unknown if placement of another implant at the site would be successful. The purpose of this paper is to report on the findings at surgical reentry and outcome of the third implant. METHODS: Eleven months after the second alveolar ridge preservation, the site was reentered. The bone graft was found to be partially soft tissue encapsulated. All encapsulated graft materials and soft tissue were removed. An implant was placed, and the alveolar defect was grafted with a demineralized bone allograft. Seventeen months after implant placement, a buccal free gingival graft was performed during which the crestal bone adjacent to the implant was found to be hard and corticated. The implant was deemed to be osseointegrated and restored after soft tissue healing. RESULTS: Twenty-five months after implant placement, the third implant remained functional and asymptomatic with the peri-implant bone exhibiting normal trabeculation. CONCLUSIONS: Implant therapy can be successful following treatment and resolution of perigraftitis. KEY POINTS: Perigraftitis may play a contributing role in the biologic complications of implants that have been placed into grafted bone. Perigraftitis may be successfully resolved by completely removing all grafted bone. Once perigraftitis has been eliminated, an implant may be successfully placed.

Effect of EDTA Gel on Residual Subgingival Calculus and Biofilm: An In Vitro Pilot Study.

BACKGROUND: Residual calculus, following scaling and root planing (SRP), is associated with persistent inflammation and the progression of periodontitis. This study examined the effects of a 24% neutral ethylenediaminetetraacetic acid (EDTA) gel on subgingival calculus and biofilms. METHODS: Eleven single-rooted teeth extracted because of severe periodontal disease were randomly assigned to the following treatment groups: (1) three teeth served as untreated controls; (2) three teeth were treated by scaling and root planing (SRP) only; and (3) three teeth were treated by SRP + EDTA. The remaining two teeth, one SRP only and the other SRP + EDTA were designated for energy-dispersive X-ray spectroscopy (EDS) analysis. EDTA gel was placed on the SRP surface for 2 min and then burnished with a sterile cotton pellet. RESULTS: SRP + EDTA treated specimens exhibited severely damaged biofilm and the disruption of the extracellular polymeric matrix. EDS scans of the smear layer and calculus featured reductions in the Weight % and Atomic % for N, F, Na, and S and increases in Mg, P, and Ca. CONCLUSIONS: A 25% neutral EDTA gel was applied after SRP severely disrupted the residual biofilm and altered the character of dental calculus and the smear layer as shown by reductions in the Weight % and Atomic % for N, F, Na, and S and increases in Mg, P, and Ca.

Ancient DNA confirms diverse origins of early post-Columbian cattle in the Americas.

Before the arrival of Europeans, domestic cattle (Bos taurus) did not exist in the Americas, and most of our knowledge about how domestic bovines first arrived in the Western Hemisphere is based on historical documents. Sixteenth-century colonial accounts suggest that the first cattle were brought in small numbers from the southern Iberian Peninsula via the Canary archipelago to the Caribbean islands where they were bred locally and imported to other circum-Caribbean regions. Modern American heritage cattle genetics and limited ancient mtDNA data from archaeological colonial cattle suggest a more complex story of mixed ancestries from Europe and Africa. So far little information exists to understand the nature and timing of the arrival of these mixed-ancestry populations. In this study we combine ancient mitochondrial and nuclear DNA from a robust sample of some of the earliest archaeological specimens from Caribbean and Mesoamerican sites to clarify the origins and the dynamics of bovine introduction into the Americas. Our analyses support first arrival of cattle from diverse locales and potentially confirm the early arrival of African-sourced cattle in the Americas, followed by waves of later introductions from various sources over several centuries.

Periodontal Therapy: Patient Outcomes-Based or Profit Center-Based?

Multiple recent articles have called for outcomes-based and patient-centered guidelines for periodontal therapy.1-6 Simply put, periodontal therapy must be in accord with evidence-based treatment and doing what is right for the patient at the clinical level. With this in mind, the present authors contend that many patients with periodontal disease are not receiving acceptable and timely treatment and disease management.

A randomized double-blind clinical trial evaluating comparative plaque and gingival health associated with commercially available stannous fluoride-containing dentifrices as compared to a sodium fluoride control dentifrice.

BACKGROUND: Gingivitis is a non-specific inflammatory lesion in response to the accumulation of oral biofilm and is a necessary precursor to periodontitis. Enhanced oral hygiene practices, including utilization of a dentifrice that could significantly improve plaque accumulation and gingival inflammation, is desirable to prevent and treat gingivitis and potentially prevent progression to periodontitis. This clinical study aimed to investigate the effect of a new stannous fluoride-containing dentifrice with 2.6% ethylenediamine tetra acetic acid (EDTA) as an anti-tartar agent to reduce plaque index and gingival index over a 3-month study period compared to other commercially-available fluoride-containing dentifrices. METHODS: This double-blind, randomized controlled clinical study evaluated plaque, gingival inflammation, and sulcular bleeding in patients using one of five commercially available fluoride-containing dentifrices The dentifrices tested contained: 0.454% stannous fluoride and 2.6% EDTA (D1), 0.24% sodium fluoride (C), and 0.454% stannous fluoride (D2-D4). One hundred fifty subjects participated over a 3-month period. Co-primary endpoints were improvements in plaque index (PI) and modified gingival index (mGI) from baseline values. No professional cleaning was performed during the study period. RESULTS: All subjects in the study demonstrated statistically significant improvements in all measures of oral hygiene over the 3-month study period. Subjects using dentifrice 1 (D1) showed statistically significantly greater reductions in PI, mGI, and modified sulcular bleeding index (mSBI) compared with all other commercially-available dentifrices tested (p < 0.00001). CONCLUSIONS: A new dentifrice with 0.454% stannous fluoride and 2.6% EDTA demonstrated significant improvements in clinical parameters associated with gingivitis compared to other sodium and stannous fluoride containing dentifrices.

Determination of structural models of the complex between the cytoplasmic domain of erythrocyte band 3 and ankyrin-R repeats 13-24.

The adaptor protein ankyrin-R interacts via its membrane binding domain with the cytoplasmic domain of the anion exchange protein (AE1) and via its spectrin binding domain with the spectrin-based membrane skeleton in human erythrocytes. This set of interactions provides a bridge between the lipid bilayer and the membrane skeleton, thereby stabilizing the membrane. Crystal structures for the dimeric cytoplasmic domain of AE1 (cdb3) and for a 12-ankyrin repeat segment (repeats 13-24) from the membrane binding domain of ankyrin-R (AnkD34) have been reported. However, structural data on how these proteins assemble to form a stable complex have not been reported. In the current studies, site-directed spin labeling, in combination with electron paramagnetic resonance (EPR) and double electron-electron resonance, has been utilized to map the binding interfaces of the two proteins in the complex and to obtain inter-protein distance constraints. These data have been utilized to construct a family of structural models that are consistent with the full range of experimental data. These models indicate that an extensive area on the peripheral domain of cdb3 binds to ankyrin repeats 18-20 on the top loop surface of AnkD34 primarily through hydrophobic interactions. This is a previously uncharacterized surface for binding of cdb3 to AnkD34. Because a second dimer of cdb3 is known to bind to ankyrin repeats 7-12 of the membrane binding domain of ankyrin-R, the current models have significant implications regarding the structural nature of a tetrameric form of AE1 that is hypothesized to be involved in binding to full-length ankyrin-R in the erythrocyte membrane.

Randomized clinical trials: is periodontal research good for patients?

Randomized controlled trials, in which randomization is used to allocate patients to a treatment arm, are a relatively new concept. Randomized controlled trials are increasingly high-stakes endeavors requiring a high level of planning and considerable financial support. Randomized controlled trials are the gold standard by which effectiveness of various treatments or interventions are determined. However, the methods involved in randomized controlled trials raise the question: is clinical research good for the participants? This paper discusses patient-centered issues relating to randomized controlled trials, for example, whether the informed-consent process results in subjects who are knowledgeable and informed about their participation, which, in turn, involves patient autonomy, health literacy and treatment preferences. Other issues discussed are those of statistical vs. clinical significance, professional ethics and ethical justification for randomized controlled trials, and differences in perceptions between patients and clinicians regarding the level of care being provided by the randomized controlled trials. Because our goal, as clinicians, is to provide treatment that improves the quality of life for the patient, it would seem logical that randomized controlled trials should include variables rated as important by patients as valid outcome measures. As clinicians and researchers, we can no longer afford to view randomized controlled trials from an ivory tower. Research participants, although autonomous agents, are inherently different from the patient seeking clinical care. Researchers have an ethical responsibility to consider the informed consent process as it relates to the subject's health literacy and potential for therapeutic and procedural misperceptions.

Diode laser offers minimal benefit for periodontal therapy.

Current evidence indicates that use of diode lasers in the treatment of periodontitis--either as a monotherapy or adjunctive to traditional therapy--offers minimal benefit. Further, subgingival application of the diode laser during nonsurgical periodontal therapy can result in undesired outcomes, even when using manufacturer-recommended parameters.

Engineering peptide-polymer hybrids for targeted repair and protection of cervical lesions.

By 2060, nearly 100 million people in the U.S. will be over age 65 years. One-third of these older adults will have root caries, and nearly 80% will have dental erosion. These conditions can cause pain and loss of tooth structure that interfere with eating, speaking, sleeping, and quality of life. Current treatments for root caries and dental erosion have produced unreliable results. For example, the glass-ionomer-cement or composite-resin restorations used to treat these lesions have annual failure rates of 44% and 17%, respectively. These limitations and the pressing need to treat these conditions in the aging population are driving a focus on microinvasive strategies, such as sealants and varnishes. Sealants can inhibit caries on coronal surfaces, but they are ineffective for root caries. For healthy, functionally independent elders, chlorhexidine varnish applied every 3 months inhibits root caries, but this bitter-tasting varnish stains the teeth. Fluoride gel inhibits root caries, but requires prescriptions and daily use, which may not be feasible for some older patients. Silver diamine fluoride can both arrest and inhibit root caries but stains the treated tooth surface black. The limitations of current approaches and high prevalence of root caries and dental erosion in the aging population create an urgent need for microinvasive therapies that can: (a) remineralize damaged dentin; (b) inhibit bacterial activity; and (c) provide durable protection for the root surface. Since cavitated and non-cavitated root lesions are difficult to distinguish, optimal approaches will treat both. This review will explore the multi-factorial elements that contribute to root surface lesions and discuss a multi-pronged strategy to both repair and protect root surfaces. The strategy integrates engineered peptides, novel polymer chemistry, multi-scale structure/property characterization and predictive modeling to develop a durable, microinvasive treatment for root surface lesions.

Clinical Decisions Based on the 2018 Classification of Periodontal Diseases.

The absence of widely accepted treatment decision points for the management of periodontitis can be problematic for the dental profession and patients. After conducting a thorough review of published peer-reviewed studies, the authors developed basic therapeutic decision points for the management of periodontitis based on the 2018 classification of periodontal diseases. These decision points were utilized to outline appropriate treatments, which include: patient commitment to a thorough daily self-care regimen, the definitive elimination of etiological factors, professional treatment that includes the complete removal of residual bacterial biofilm (plaque), the definitive removal of both supragingival and subgingival calculus, and, in advanced disease, possible tissue augmentation and regenerative surgery. Advanced therapies to accomplish an acceptable therapeutic end point are indicated in stage III and stage IV periodontitis. The presented decision points for the treatment of periodontitis offer a basis for the ethical care and management of patients in all stages of periodontitis.

Calculus as a Risk Factor for Periodontal Disease: Narrative Review on Treatment Indications When the Response to Scaling and Root Planing Is Inadequate.

BACKGROUND: Based on the 2018 classification of periodontal disease, a series of articles have been published describing the decision points of periodontal therapy and how the findings collected at those decision points can be used as guidelines for periodontal therapy. The articles are reviewed with a focus on the finding of inadequate calculus removal at the decision points and how that finding impacts treatment outcomes. METHODS: A narrative review of the literature discussing the influence of calculus on inflammation was performed and the effects of inadequate removal of calculus during periodontal therapy were analyzed in light of the 2018 classification of periodontal disease, the decision points of periodontal therapy, and the guidelines of periodontal therapy. RESULTS: The published literature supports that calculus is a major risk factor for periodontal inflammation. Recent studies indicate that the pathologic risk of calculus goes beyond the retention of biofilm and may represent a different pathophysiologic pathway for periodontal disease separate from the direct action of biofilm. The inadequate removal of calculus is a factor in the failure of periodontal therapy. CONCLUSIONS: The inadequate removal of calculus plays an important role in the frequent failure of non-surgical periodontal therapy to eliminate inflammation.

Local connectivity and synaptic dynamics in mouse and human neocortex.

We present a unique, extensive, and open synaptic physiology analysis platform and dataset. Through its application, we reveal principles that relate cell type to synaptic properties and intralaminar circuit organization in the mouse and human cortex. The dynamics of excitatory synapses align with the postsynaptic cell subclass, whereas inhibitory synapse dynamics partly align with presynaptic cell subclass but with considerable overlap. Synaptic properties are heterogeneous in most subclass-to-subclass connections. The two main axes of heterogeneity are strength and variability. Cell subclasses divide along the variability axis, whereas the strength axis accounts for substantial heterogeneity within the subclass. In the human cortex, excitatory-to-excitatory synaptic dynamics are distinct from those in the mouse cortex and vary with depth across layers 2 and 3.

The CEJ: a biofilm and calculus trap.

There is a direct correlation between increasing periodontal probing depth and increasing presence of residual biofilms and calculus. One of the more common areas to find postscaling and root-planing residual biofilm and calculus is the cemento-enamel junction (CEJ)--an area that in most cases is easily accessible. Yet few studies have addressed the question of why the CEJ is a potential biofilm and calculus trap. This article discusses the various anatomical relationships of enamel, dentin, and cementum at the CEJ, the role of CEJ anatomy in the retention of biofilm (with SEM photographs as supporting evidence), and the biological and clinical implications of subgingival residual biofilm and calculus.

A re-evaluation of scaling and root planing.

BACKGROUND: Extensive reviews on the role of scaling and root planing (SRP) in the treatment of periodontitis have been previously published. This commentary will address the importance of subgingival calculus in the progression and treatment of periodontitis and addresses factors that make the execution of a "definitive" SRP a critical part of therapy. METHODS: A search for articles, using keywords relevant to the subject , (e.g., periodontitis, dental scaling, root planing, dental calculus, biofilm, inflammation) was conducted using PubMed, Ovid Medline, Cochrane Reviews and the ADA Center for Evidence Based Dentistry data bases. Additionally, references cited in relevant articles were also considered. RESULTS: Surfaces of subgingival calculus are covered with a biofilm of metabolically active bacteria. Periodontal inflammation is clearly related to the presence of calculus and biofilm. The primary goal of SRP is removal of subgingival calculus and biofilm deposits to create a biologically compatible root surface and reduce the inflammatory burden. Current evidence suggests that inflammation associated with periodontal infections affects both the immediate oral environment and the patient's systemic health. CONCLUSION: SRP is still critical to the treatment of periodontitis. SRP involving deep probing depths (≥ 5 mm) and root surfaces with anatomical and surface irregularities, regardless of the type of instrumentation, requires time, exceptional skill and perseverance, and patient compliance with periodontal maintenance. Sites with persistent nonresponding probing depths and signs of inflammation following a definitive SRP, should be considered for surgical intervention.

SEM Evaluation of the Effects of Laser-Mediated Implant Surface Decontamination: An In Situ Human Pilot Study.

Successful treatment of peri-implantitis requires decontamination of implant surfaces exposed to biofilms and byproducts of tissue inflammation. In this regard, dental lasers may provide a clinical benefit. While the inherent characteristics of specific laser wavelengths may damage titanium implant surfaces, in vitro and animal studies have shown that damage to the target surface can be avoided with the selection of appropriate laser parameters. In this in situ human study, five hopeless implants were irradiated, each by one of the following lasers: Nd:YAG (1,064 nm), Er,Cr:YSGG (2,780 nm), Er:YAG (2,940 nm), CO2 (9,300 nm), and CO2 (10,600 nm) at their recommended settings. All implants were then removed and examined under scanning electron microscopy for the presence of residual bacteria and to assess the extent of damage to the implant surface. An additional implant (implant no. six) was irradiated and evaluated by the Limulus Amebocyte Lysate test for the presence of residual lipopolysaccharide endotoxin. The results showed that while there were localized areas of heat-related damage to an implant surface following laser irradiation, residual bacteria were rarely noted. Additionally, the Limulus Amebocyte Lysate test indicated a nearly complete removal of endotoxin. With the use of appropriate settings, all current dental lasers can be utilized for implant surface decontamination in a human.