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.

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.

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.

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.

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.

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.

Efficacy of Removal of Residual Dental Cement by Laser, Ultrasonic Scalers, and Titanium Curette: An In Vitro Study.

The purpose of this study was to conduct an in vitro evaluation of the efficacy of six dental lasers, two ultrasonic scalers, and a titanium curette in the removal of dental cement from the surface of an implant. The study used a total of 39 dental implants, representing three different surface textures. The implants were divided into 13 groups with one of each of the three surface textures in a group. A standardized amount of modified resin dental cement was applied to the implant surface. Each test instrument was used as a monotherapy. Additionally, three of the lasers were used as part of a dual therapy in conjunction with the piezo ultrasonic scaler. Laser irradiation was limited to 2 minutes. Following treatment, implants were graded visually and by scanning electron microscopy (SEM) for the presence of unremoved cement and concomitant damage, if any, to the implant surface. The results showed that no treatment removed all residual cement from any of the three implant surfaces, although specific protocols appeared more effective than others. Implant surface damage was frequently observed, both visually and by SEM, and appeared to result from laser irradiation and the use of ultrasonic scaling instruments.

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.

Evaluating efficacy of a novel dentifrice in reducing probing depths in Stage I and II periodontitis maintenance patients: A randomized, double-blind, positive controlled clinical trial.

BACKGROUND: Compliance to periodontal maintenance therapy (PMT) is essential for long-term periodontal health. Between PMT visits, patients must maintain good oral hygiene. A dentifrice with demonstrable clinical benefits for use between PMT visits would be highly desirable. The aim of this clinical study was to investigate the effect of a novel dental gel on probing depths (PD) and inflammation when used as a home care dentifrice in Stage I and II periodontitis patients. METHODS: This double-blind clinical study randomized 65 subjects with Stage I and II periodontitis to the novel dental gel containing 2.6% EDTA, and a commercially available anti-gingivitis dentifrice with 0.454% stannous fluoride. Primary endpoint was PD at 6 months for those sites with baseline PD ≥ 4 mm and secondary endpoints included whole mouth mean scores of modified gingival index (MGI), modified sulcus bleeding index (mSBI) and plaque index (PI). No SRP was performed at baseline. RESULTS: Subjects using the novel dentifrice showed significant PD reductions of 1.18 mm (from 4.27 mm at baseline to 3.09 mm at 6 months) compared to 0.93 mm (from 4.23 mm at baseline to 3.30 mm at 6 months) shown for those using the positive control dentifrice. Difference between treatments at 6 months was 0.21 mm with P-value = 0.0126. Significant improvements in MGI (P = 0.0000), mSBI (P = 0.0000), and PI (P = 0.0102) were also observed in 6 months. CONCLUSION: The novel dentifrice showed significant reductions in PD and gingival inflammation over 6 months solely as a home care dentifrice without baseline SRP in Stage I and II periodontitis maintenance patients.

Periodontal Risk Assessment Based on Dental and Gingival Morphology: A Comparative Analysis of African Versus Asian American Cohorts.

FOCUSED CLINICAL QUESTION: With the 2018 AAP/EFP disease classification with the staging and grading systems, does risk assessment for different ethnic group result in a different focus for clinical needs? This comparative analysis aimed to assess two previously reported cohort studies in African-American (Af-A) and Asian-American (As-A) as to the risk for these two populations for clinical attachment loss (CAL) and gingival phenotype. SUMMARY: In comparison of As-A and Af-A cohorts, As-A had higher frequency of thin tissue phenotype, less width of keratinized gingiva (KGW), and more gingival recession (GR). On other hands, Af-A showed higher prevalence of thick phenotype, longer total tooth length and root length (RL). These gingival and dental anatomical patterns suggest there are differential risk for GR, patterns for CAL, and periodontal prognosis between two cohorts. CONCLUSION(S): Because of nature of dental and gingival anatomy between these two cohorts, As-A are more susceptible in GR and the short RL affords this population less ability to withstand the clinical presentation of periodontal disease. From a therapeutic perspective, clinicians should evaluate patients with different risk assessment based on their dental and gingival characterization. Af-A may have clinical characteristics that makes this population less at risk for mucogingival defects. Conversely, phenotype modification therapy should be considered when treating As-A because of the high prevalence of thin tissue phenotype, inadequate KGW, and GR. Clinicians should also diligently monitor periodontal CAL around the teeth with shorter RL in periodontal or orthodontic therapy for better teeth prognosis.