An in-vitro analysis of the accuracy of different guided surgery systems - They are not all the same.

OBJECTIVES: Different static computer-assisted implant surgery (sCAIS) systems are available that are based on different design concepts. The objective was to assess seven different systems in a controlled environment. MATERIALS AND METHODS: Each n = 20 implants were placed in identical mandible replicas (total n = 140). The systems utilized either drill-handles (group S and B), drill-body guidance (group Z and C), had the key attached to the drill (group D and V), or combined different design concepts (group N). The achieved final implant position was digitized utilizing cone-beam tomography and compared with the planned position. The angular deviation was defined as the primary outcome parameter. The means, standard deviation, and 95%-confidence intervals were analyzed statistically with 1-way ANOVA. A linear regression model was applied with the angle deviation as predictor and the sleeve height as response. RESULTS: The overall angular deviation was 1.94 ± 1.51°, the 3D-deviation at the crest 0.54 ± 0.28 mm, and at the implant tip 0.67 ± 0.40 mm, respectively. Significant differences were found between the tested sCAIS systems. The angular deviation ranged between 0.88 ± 0.41° (S) and 3.97 ± 2.01° (C) (p < .01). Sleeve heights ≤4 mm are correlated with higher angle deviations, sleeve heights ≥5 mm with lower deviations from the planned implant position. CONCLUSIONS: Significant differences were found among the seven tested sCAIS systems. Systems that use drill-handles achieved the highest accuracy, followed by the systems that attach the key to the drill. The sleeve height appears to impact the accuracy.

Precision and trueness of computer-assisted implant placement using static surgical guides with open and closed sleeves: An in vitro analysis.

OBJECTIVES: The aim of this in vitro study was to determine accuracy defined by trueness and precision of computer-assisted implant surgery comparing two guided surgery kits designed for either closed sleeves or open sleeves with a lateral window. MATERIAL AND METHODS: Each n=20 implants were placed fully guided (sleeve-bone distance of 2 or 4 mm) in identical replicas using a surgical guide with both closed sleeve or an open sleeve, partially guided, or free hand. The achieved implant position was digitized and compared with the planned position. Trueness and precision were determined. The angular deviation was defined as the primary outcome parameter. The means, standard deviation, and 95%-confidence intervals were analyzed statistically with 1-way ANOVA and the Scheffé procedure. RESULTS: The accuracy of guided implant placement using closed and open sleeves was comparable when the sleeve-bone distance was 2 mm. Accuracy decreased when the sleeve-bone distance increased in both fully guided groups, more so in the open than in the closed sleeve group. The least accurate method was the free-hand group. Partially guided implant surgery was more accurate than free-hand placement, but less accurate than the fully guided groups with 2-mm sleeve-bone distance. CONCLUSIONS: The closer the sleeve to the bone, the more accurate and precise is computer-assisted implant surgery using a closed system and a system using open sleeves. Partially guided implant surgery using only the static guide for the pilot drill is less accurate than both fully guided approaches, but more accurate than free-hand surgery.

Patient-reported outcomes following guided bone regeneration: Correlation with clinical parameters.

OBJECTIVES: Postoperative oral health-related quality of life is procedure-dependent and may vary during early healing. There is scarce evidence on patient-reported outcome measures (PROMs) after extraction and guided bone regeneration (GBR) or on the clinical parameters influencing PROMs. This prospective observational study aimed to evaluate PROMs during the first 2 weeks following extraction and GBR and correlate them with clinical parameters. METHODS: Patients undergoing extraction and GBR (bone graft and resorbable membrane) at a single tooth-bound site were recruited. PROMs (pain, swelling, difficulty of mouth opening, and OHIP-14) were recorded immediately preoperatively, and at 2, 7, and 14 days postoperatively. Flap advancement, gingival and mucosal thickness, duration of surgery, and wound opening were the clinical parameters assessed. RESULTS: Twenty-seven patients were included. All PROMs peaked on postoperative day 2, decreased subsequently and were significantly correlated with each other. Although 41-56% of patients reported moderate to severe pain, swelling, or mouth opening difficulty on day 2, most patients experienced mild or no symptoms throughout the postoperative period. Pain, swelling and difficulty of mouth opening were determinants of OHIP-14 and were correlated with all OHIP-14 domains during different time points. Wound opening peaked on day 7. Flap advancement, soft tissue thickness, wound opening, duration of surgery and preoperative PROMs affected postoperative PROMs. CONCLUSIONS: Within the limitations of the present study, postoperative symptoms after guided bone regeneration are worst on day 2 and oral health-related quality of life is significantly impacted by pain, swelling, difficulty of mouth opening, surgery duration and flap advancement. CLINICAL SIGNIFICANCE: This is the first study to report PROMs following extraction and GBR with particulate bone graft and resorbable membrane in preparation for implant placement. It will help guide both practitioners and patients on what should be the anticipated experiences following such a routinely performed surgery.

Post-surgical emergency after-hours calls: Prevalence, concerns, and management.

OBJECTIVE: The purpose of this study was to investigate the prevalence, nature, and management of post-surgical emergency after-hours calls in a dental school setting with predoctoral students, graduate students/residents, and faculty providers. METHODS: A patient chart review (March 2018-February 2020) for post-surgical calls through the emergency after-hours pager system was conducted at the Marquette University School of Dentistry. The total number of surgical procedures, procedure type, the timing of call, operator experience, concern, and recommendation given during the call were documented. RESULTS: During the review period, 83 calls (from 75 patients) were recorded after 8,487 surgical procedures (1% of procedures). Patients called 5.4 ± 0.8 days postoperatively. Procedure type affected call prevalence (p = 0.04), with most calls made after extractions (69.9% of all calls; 1% of extractions; 58/5,725), implant placement (6%; 0.9% of implant placements; 5/530) and periodontal plastic surgery (6%; 3.1% of all plastic surgeries; 5/161). The most common concern was pain (72.3%), then swelling (36.1%), bleeding (12%), and infection (9.6%). Operator experience did not affect call prevalence. Recommendations given were next business day follow-up (79.5%), reinforcement of already given postoperative instructions (51.8%), prescription (15.7%), and hospital emergency department (ED) visit (7.2%). CONCLUSIONS: Post-surgical emergency after-hours calls in a dental school setting occur within the first postoperative week and are rare, unrelated to operator experience, typically prompted by pain, and rarely resulting in referral to hospital ED. The use of a pager system is adequate for the management of after-hours emergencies and may reduce self-referrals to the hospital ED.

Inhibition of Candida albicans and Mixed Salivary Bacterial Biofilms on Antimicrobial Loaded Phosphated Poly(methyl methacrylate).

Biofilms play a crucial role in the development of Candida-associated denture stomatitis. Inhibition of microbial adhesion to poly(methyl methacrylate) (PMMA) and phosphate containing PMMA has been examined in this work. C. albicans and mixed salivary microbial biofilms were compared on naked and salivary pre-conditioned PMMA surfaces in the presence or absence of antimicrobials (Cetylpyridinium chloride [CPC], KSL-W, Histatin 5 [His 5]). Polymers with varying amounts of phosphate (0-25%) were tested using four C. albicans oral isolates as well as mixed salivary bacteria and 24 h biofilms were assessed for metabolic activity and confirmed using Live/Dead staining and confocal microscopy. Biofilm metabolism was reduced as phosphate density increased (15%: p = 0.004; 25%: p = 0.001). Loading of CPC on 15% phosphated disks showed a substantial decrease (p = 0.001) in biofilm metabolism in the presence or absence of a salivary pellicle. Salivary pellicle on uncharged PMMA enhanced the antimicrobial activity of CPC only. CPC also demonstrated remarkable antimicrobial activity on mixed salivary bacterial biofilms under different conditions displaying the potent efficacy of CPC (350 µg/mL) when combined with an artificial protein pellicle (Biotene half strength).

Novel molecules for intra-oral delivery of antimicrobials to prevent and treat oral infectious diseases.

New molecules were designed for efficient intra-oral delivery of antimicrobials to prevent and treat oral infection. The salivary statherin fragment, which has high affinity for the tooth enamel, was used as a carrier peptide. This was linked through the side chain of the N-terminal residue to the C-terminus of a defensin-like 12-residue peptide to generate two bifunctional hybrid molecules, one with an ester linkage and the other with an anhydride bond between the carrier and the antimicrobial components. They were examined for their affinity to a HAP (hydroxyapatite) surface. The extent of the antimicrobial release in human whole saliva was determined using 13C-NMR spectroscopy. The candidacidal activity of the molecules was determined as a function of the antimicrobial release from the carrier peptide in human saliva. The hybrid-adsorbed HAP surface was examined against Candida albicans and Aggregatibacter actinomycetemcomitans using the fluorescence technique. The bifunctional molecules were tested on human erythrocytes, GECs (gingival epithelial cells) and GFCs (gingival fibroblast cells) for cytotoxicity. They were found to possess high affinity for the HAP mineral. In human whole saliva, a sustained antimicrobial release over a period of more than 40-60 h, and candidacidal activity consistent with the extent of hybrid dissociation were observed. Moreover, the bifunctional peptide-bound HAP surface was found to exhibit antimicrobial activity when suspended in clarified human saliva. The hybrid peptides did not show any toxic influence on human erythrocytes, GECs and GFCs. These novel hybrids could be safely used to deliver therapeutic agents intra-orally for the treatment and prevention of oral infectious diseases.

Effect of phosphate group addition on the properties of denture base resins.

STATEMENT OF PROBLEM: Acrylic resins are prone to microbial adherence, especially by Candida albicans. Surface-charged resins alter the ionic interaction between the denture resin and Candida hyphae, and these resins are being developed as a means to reduce microbial colonization on the denture surface. PURPOSE: The purpose of this study was to investigate the physical and mechanical properties of phosphate-containing polymethyl methacrylate resins for their suitability as a denture material. MATERIAL AND METHODS: Using PMMA with cross-linker (Lucitone 199) as a control, 4 experimental groups containing various levels of phosphate with and without cross-linker were generated. The properties examined were impact strength, fracture toughness, wettability (contact angle), and resin bonding ability to denture teeth. Impact strength was tested in the Izod configuration (n=16), and fracture toughness (n=13) was measured using the single-edge notched bend test. Wettability was determined by calculating the contact angle of water on the material surface (n=12), while ISO 1567 was used for bonding ability (n=12). The data were analyzed by 1- and 2-way ANOVA (alpha=.05). RESULTS: A trend of increased hydrophilicity, as indicated by lower contact angle, was observed with increased concentrations of phosphate. With regard to the other properties, no significant differences were found when compared with the control acrylic resin. CONCLUSIONS: No adverse physical effect due to the addition of a phosphate-containing monomer was found in the acrylic denture resins. Additional mechanical and physical properties, biocompatibility, and clinical efficacy studies are needed to confirm the in vivo anti-Candida activity of these novel resins.

The effect of EDTA in attachment gain and root coverage.

Root surface biomodification using low pH agents such as citric acid and tetracycline has been proposed to enhance root coverage following connective tissue grafting. The authors hypothesized that root conditioning with neutral pH edetic acid would improve vertical recession depth, root surface coverage, pocket depth, and clinical attachment levels. Twenty teeth in 10 patients with Miller class I and II recession were treated with connective tissue grafting. The experimental sites received 24% edetic acid in sterile distilled water applied to the root surface for 2 minutes before grafting. Controls were pretreated with only sterile distilled water. Measurements were evaluated before surgery and 6 months after surgery. Analysis of variance was used to determine differences between experimental and control groups. We found significant postoperative improvements in vertical recession depth, root surface coverage, and clinical attachment levels in test and control groups, compared to postoperative data. Pocket depth differences were not significant (P<.01).

Intraoral delivery of antimicrobials.

Antimicrobial therapies for oral diseases have been in use for centuries, but have undergone rapid changes in the last decade. In the coming years, antimicrobial strategies will become more sophisticated and efficacy will be greatly improved as new therapeutic technologies emerge. New delivery systems for common antimicrobials and novel agents to modulate the immune system, as well as biofilm formation and maturation, may be on the horizon. This review describes the development and the application of intraoral antimicrobial drug delivery in the oral environment. Current clinical uses of antimicrobials as well as future approaches to the treatment and prevention of oral infectious diseases are discussed.

Prevention of periodontal diseases.

The ultimate goal of periodontal disease prevention is to maintain the dentition over a lifetime in a state of health, comfort, and function in an aesthetically pleasing presentation. This article focuses on primary and secondary periodontal disease prevention as they relate to gingivitis and periodontitis. Risk assessment, mechanical plaque control, chemical plaque control, current clinical recommendations for optimal prevention, and future preventive strategies are discussed.

Current status of defensins and their role in innate and adaptive immunity.

Naturally occurring antimicrobial cationic polypeptides play a major role in innate and adaptive immunity. These polypeptides are found to be either linear and unstructured or structured through disulfide bonds. Among the structured antimicrobial polypeptides, defensins comprise a family of cysteine-rich cationic polypeptides that contribute significantly to host defense against the invasion of microorganisms in animals, humans, insects and plants. Their wide-spread occurrence in various tissues of these diverse organisms, and their importance in innate and adaptive immunity have led to their identification, isolation and characterization. A large volume of literature is available on defensins' occurrence, structural characterization, gene expression and regulation under normal and pathological conditions. Much has also been published regarding their antimicrobial, antiviral and chemoattractive properties, and their molecular and cellular interactions. In this review, we describe the current status of our knowledge of defensins with respect to their molecular, cellular and structural biology, their role in host defense, future research paradigms and the possibility of their utilization as a new class of non-toxic antimicrobial agents and immuno-modulators.

Six-month comparison of powered versus manual toothbrushing for safety and efficacy in the absence of professional instruction in mechanical plaque control.

BACKGROUND: Reports suggest powered toothbrushing may provide some clinical benefit over manual tooth-brushing, but most studies have been of short duration with subjects trained in toothbrush use. The aim was to determine if the oscillating-rotating powered brush (PB) could safely provide clinical benefits over and above a manual brush (M) in subjects with no formal instruction or experience in powered brush use. METHODS: This 6-month, single-masked, parallel design, randomized clinical trial compared the PB with an American Dental Association (ADA)-accepted soft-bristle manual brush in a non-flossing gingivitis population (n = 157). Subjects were given written instructions but no demonstration on toothbrush use at baseline. Efficacy was assessed by changes in gingival inflammation, plaque, calculus, and stain, while changes in clinical attachment levels and recession measurements provided safety data. A prophylaxis was provided after baseline assessment. The 6-month plaque index (PI) was recorded immediately post-brushing after covert timing of the subjects, and correlation analyses were run to assess the relationship of brushing time to PI. Paired t tests, analysis of variance (ANOVA), and analysis of covariance (ANCOVA) were used to assess within and between treatment group differences for PB (n = 76) versus M groups (n = 81). RESULTS: Measures of inflammation showed a statistically significant drop for both brushes at 3 and 6 months. Mean overnight full-mouth PI scores were significantly lower at 3 months for the PB (1.57) compared to the M group (1.80), P = 0.0013. Immediate post-brushing PI at 6 months was also significantly lower for the PB (1.10) versus M (1.39) (P= 0.0025). There was an overall negative correlation for PI and brushing time (r = -0.377, P= 0.0001). Mean calculus index (CI) scores were lower for the PB at 3 (P= 0.0304) and 6 months (P = 0.0078), while no significant differences in stain were observable. Clinical attachment level and recession measurements showed no significant between-group changes from baseline for either brush on canine teeth or on teeth with recession at baseline. CONCLUSION: The oscillating-rotating toothbrush safely provides clinical benefits in plaque and calculus reduction over a manual brush even in subjects with no formal oral hygiene instruction.

Exposure to the dental environment and prevalence of respiratory illness in dental student populations.

OBJECTIVE: To determine if the prevalence of respiratory disease among dental students and dental residents varies with their exposure to the clinical dental environment. METHODS: A detailed questionnaire was administered to 817 students at 3 dental schools. The questionnaire sought information concerning demographic characteristics, school year, exposure to the dental environment and dental procedures, and history of respiratory disease. The data obtained were subjected to bivariate and multiple logistic regression analysis. RESULTS: Respondents reported experiencing the following respiratory conditions during the previous year: asthma (26 cases), bronchitis (11 cases), chronic lung disease (6 cases), pneumonia (5 cases) and streptococcal pharyngitis (50 cases). Bivariate statistical analyses indicated no significant associations between the prevalence of any of the respiratory conditions and year in dental school, except for asthma, for which there was a significantly higher prevalence at 1 school compared to the other 2 schools. When all cases of respiratory disease were combined as a composite variable and subjected to multivariate logistic regression analysis controlling for age, sex, race, dental school, smoking history and alcohol consumption, no statistically significant association was observed between respiratory condition and year in dental school or exposure to the dental environment as a dental patient. CONCLUSION: No association was found between the prevalence of respiratory disease and a student's year in dental school or previous exposure to the dental environment as a patient. These results suggest that exposure to the dental environment does not increase the risk for respiratory infection in healthy dental health care workers.

Denture polymers with antimicrobial properties: a review of the development and current status of anionic poly(methyl methacrylate) polymers.

The denture base polymer poly(methyl methacrylate) (PMMA) is highly susceptible for microbial colonization resulting in denture-associated infections. Over the years research has focused on ways to modify the PMMA properties via surface and chemical modification. These studies led to the development of new denture polymers that include anionic PMMA polymers. The new anionic polymers presented the possibility of compromising the physical and mechanical properties required for denture fabrication. These obstacles were overcome by generating anionic PMMA polymers with physical and mechanical properties suitable for denture fabrication. A large body of literature is available on the anionic PMMA polymers, their antimicrobial properties and their potential for the commercial and clinical application as dental biomaterials. This article describes a review and evaluation of the anionic PMMA polymers for their suitability to serve as denture base polymers, their antimicrobial properties, their efficacy to prevent denture-induced infection and their safety in the oral environment.

New phosphated poly(methyl methacrylate) polymers for the prevention of denture-induced microbial infection: an in vitro study.

PURPOSE: Poly(methyl methacrylate) (PMMA) has been widely used as a denture-base acrylic resin due to its excellent physical and mechanical properties. However, the material is highly prone to microbial fouling that often leads to Candida-associated denture stomatitis. Incorporation of phosphate groups into PMMA could facilitate adsorption of salivary antimicrobials and inhibit microbial adherence on the polymer surface. An in vitro study evaluated PMMA polymers containing varying amounts of phosphate group for their efficacy to inhibit Candida albicans adhesion, adsorb salivary histatin 5, and exhibit candidacidal activity. METHODS: Six PMMA polymers containing 0%, 5%, 15%, 10%, 20%, and 25% of phosphate group were synthesized by bead (suspension) polymerization technique using mixtures of methyl methacrylate and methallyl phosphate as monomers. The efficacy of the polymers to inhibit the adherence of C. albicans was examined by using human saliva-coated polymer beads and radio-labeled C. albicans cells, as compared with that of PMMA. The potency of the phosphated PMMA polymers to adsorb histatin 5 was determined by measuring the radioactivity of the adsorbed labeled-peptide on the polymer surface. The candidacidal activity of the histatin 5-adsorbed polymers was assessed by using the fluorescence technique. The percent release of the fluorescent probe calcein from the C. albicans membrane caused by the disruption of the cell membrane was determined. The data were analyzed statistically by one-way ANOVA followed by Scheffé's test (α = 0.05 and n = 6). RESULTS: The presence of ≥15% phosphate content in PMMA significantly reduced the saliva-mediated adhesion of C. albicans. Phosphated PMMA polymers showed significantly enhanced adsorption of histatin 5 in a phosphate density-dependent manner. The candidacidal activity of the histatin 5-bound polymers increased significantly with the increase in the phosphate content of the polymer. CONCLUSION: Phosphated PMMA polymers have the potential to serve as novel denture-base resins, which may reduce C. albicans colonization and prevent denture stomatitis.

Treatment of gingival recession.

Gingival recession is an intriguing and complex phenomenon. Recession frequently disturbs patients because of sensitivity and esthetics. Many surgical techniques have been introduced to treat gingival recession, including those involving autogenous tissue grafting, various flap designs, orthodontics, and guided tissue regeneration. This article describes different clinical approaches to treat gingival recession with emphasis on techniques that show promising results and root coverage.