Background Povidone-iodine (PV-I) is known to be active in vitro against periodontal bacterial pathogens, but previous studies most often used ≥5-minute contact times for PV-I testing and/or evaluated laboratory reference strains of bacterial species. This study further examined the antimicrobial effects of PV-I by using a 60-second in vitro treatment time for 10% and 5% PV-I on freshly recovered clinical isolates of subgingival biofilm bacteria from severe human periodontitis lesions. Methods Subgingival biofilm samples from 22 adults with severe periodontitis were mixed in vitro with 10% PV-I, 5% PV-I, or no PV-I (n = 22 samples per group), with residual PV-I neutralized after 60 seconds with sodium thiosulfate. The samples were then inoculated onto enriched Brucella blood agar (EBBA), with samples not treated with PV-I additionally plated onto EBBA supplemented with breakpoint concentrations of either amoxicillin, clindamycin, doxycycline, or metronidazole to detect antibiotic-resistant test species. After 7 days of anaerobic incubation, total viable microbial counts and selected red/orange complex periodontal pathogens (Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia/nigrescens, Parvimonas micra, Campylobacter rectus, Fusobacterium nucleatum, and Streptococcus constellatus) were phenotypically identified and quantitated on the EBBA plates, with additional cultivable isolates from PV-I-treated samples identified using matrix-assisted laser desorption-ionization time-of-flight (MALDI-TOF) mass spectrometry. Results Subgingival biofilm samples treated in vitro for 60 seconds with 10% or 5% PV-I yielded significantly lower mean total viable microbial counts (60-68% less) and significantly lower mean total cultivable proportions of red/orange complex periodontal pathogens (0.5%-0.7%) than samples not exposed to PV-I (14.8%) (P < 0.001), with no statistically significant differences between 10% and 5% PV-I in vitro treatments. All evaluated red/orange complex periodontal pathogens were culture-negative in 21 (95.5%) and 19 (86.4%) of the 22 subgingival biofilm samples after 10% and 5% PV-I in vitro treatment, respectively. Antibiotic-resistant and antibiotic-susceptible red/orange complex periodontal pathogens were similarly sensitive in vitro to 10% and 5% PV-I. Streptococcus species, particularly Streptococcus oralis, were the most prevalent cultivable isolates in subgingival samples treated in vitro with 10% or 5% PV-I for 60 seconds. Conclusions Both 10% and 5% PV-I significantly suppressed total viable microbial counts and red/orange complex periodontal pathogens, but not periodontal health-associated Streptococcus species, during 60 seconds of in vitro treatment on subgingival biofilm samples from patients with severe periodontitis, with no statistically significant differences in the antimicrobial activity of the two PV-I concentrations. These in vitro PV-I susceptibility findings with freshly isolated subgingival biofilm bacteria further support the clinical use of PV-I in periodontal therapy as an adjunct to mechanical root debridement in altering a pathogenic subgingival microbiome toward one compatible with periodontal health.

Aggregatibacter actinomycetemcomitans (Aa) is an important pathogen in human periodontitis, peri-implantitis and some non-oral infections. Simultaneous application of amoxicillin-metronidazole is synergistic against many Aa strains, including one resistant to both antibiotics individually. The present study evaluated the in vitro activity of amoxicillin-metronidazole in combination, as well as ciprofloxacin, on additional Aa clinical isolates resistant to both amoxicillin and metronidazole individually. A total of 26 Aa strains resistant to amoxicillin and metronidazole individually were recovered by selective culture from subgingival biofilm samples in United States patients with severe periodontitis. The clinical isolates were plated onto enriched Brucella blood agar supplemented with 8 mg/L of amoxicillin plus 16 mg/L of metronidazole to test for enhanced antimicrobial activity by the two antibiotics together, and onto Haemophilus test medium for ciprofloxacin (5 μg) disk diffusion testing. Among the 26 Aa study strains, 14 (53.9 %) were fully inhibited in vitro by the combination of amoxicillin-metronidazole, despite their resistance to both antibiotics individually. Partial inhibition by amoxicillin-metronidazole was found with 7 (26.9 %) Aa strains, whereas 5 (19.2 %) strains were unaffected by the drug combination. All 26 Aa study isolates were susceptible to ciprofloxacin. In conclusion, amoxicillin-metronidazole in combination exerted enhanced antimicrobial activity with total growth inhibition in vitro of approximately one-half of 26 Aa clinical isolates resistant to amoxicillin and metronidazole individually. All of the Aa study strains were susceptible in vitro to ciprofloxacin. These findings further support amoxicillin-metronidazole and ciprofloxacin drug therapies against susceptible Aa in oral and non-oral infections.

Background The potential synergism of spiramycin-metronidazole in combination against Aggregatibacter actinomycetemcomitans, a major pathogen in human periodontitis, peri-implantitis, and some non-oral infections, was studied in vitro in comparison to combinations of amoxicillin-metronidazole and ciprofloxacin-metronidazole.  Methods Minimal inhibitory concentrations (MICs) for spiramycin, amoxicillin, ciprofloxacin, and metronidazole were determined individually against four periodontal A. actinomycetemcomitans clinical isolates. Synergism testing for the combinations of spiramycin-metronidazole, amoxicillin-metronidazole, and ciprofloxacin-metronidazole was performed with gradient diffusion strips for each antibiotic pair placed onto A. actinomycetemcomitans-inoculated Haemophilus test medium in a cross formation at the intersection of each of their individual MICs against A. actinomycetemcomitans .Fractional inhibitory concentration index values assessed the antibiotic interactions.  Results Spiramycin and metronidazole individually had poor antimicrobial activity against A. actinomycetemcomitans. However, lower MIC values and less A. actinomycetemcomitans resistance were found for both antibiotics when tested in combination. Spiramycin-metronidazole synergism was additionally detected against one A. actinomycetemcomitans clinical isolate. In comparison, combinations of amoxicillin-metronidazole and ciprofloxacin-metronidazole exhibited antimicrobial synergism against all four A. actinomycetemcomitans strains.  Conclusions Spiramycin and metronidazole exerted greater in vitro antimicrobial activity in combination than individually against A. actinomycetemcomitans. Antimicrobial synergism between spiramycin and metronidazole was also found with one A. actinomycetemcomitans clinical isolate, representing the first detection of spiramycin-metronidazole synergism against A. actinomycetemcomitans. However, antimicrobial synergism against A. actinomycetemcomitans was less frequently detected with spiramycin-metronidazole as compared to combinations of amoxicillin-metronidazole or ciprofloxacin-metronidazole. These findings may help clinicians in the selection of effective antimicrobial therapies against oral and non-oral infections involving A. actinomycetemcomitans.

Background Selenomonas noxia is a putative periodontal pathogen in subgingival biofilm communities. This study compared the subgingival prevalence and levels of S. noxia in those with severe periodontitis and those with periodontal health and assessed the in vitro antibiotic susceptibility of the species. Methods Subgingival biofilm samples from 206 adults with stage III (severe) periodontitis and 48 adults with periodontal health were examined with an S. noxia-specific whole chromosomal nucleic acid probe. Minimum inhibitory concentration (MIC) values of six antibiotics against S. noxia were determined in vitro with antibiotic gradient strips. Results Selenomonas noxia was more frequently detected in patients with severe periodontitis (53.4%) than persons with periodontal health (20.8%) (2.6-fold more frequent, p = 0.0001, Fisher's exact test). Heavy subgingival colonization by S. noxia (≥106 cells/subject subgingival specimen) was also more frequent in persons with severe periodontitis (16.0%) than those with periodontal health (2.1%) (7.6-fold more frequent, p = 0.008, Fisher's exact test). Selenomonas noxia was susceptible in vitro to amoxicillin, azithromycin, clindamycin, doxycycline, and metronidazole (all MIC values ≤ 0.75 mg/L) but resistant to spiramycin (MIC > 32 mg/L). Conclusions Selenomonas noxia was significantly more prevalent at significantly higher subgingival levels in patients with severe periodontitis than adults with periodontal health. However, heavy S. noxia subgingival colonization was present in only a subset of severe periodontitis patients and rarely in those with periodontal health. Selenomonas noxia was susceptible in vitro to several antibiotics of potential therapeutic use in periodontitis therapy, with the exception of spiramycin. Selenomonas noxia may contribute to periodontitis in patients harboring high subgingival numbers of the organism.

Ramus frame dental implants were retrospectively studied in 360 adults with severely atrophic edentulous mandibles. Patient records up to 12 years post-treatment were independently reviewed after a single clinician surgically placed titanium long-arm ("Tatum") ramus frame implants and immediately loaded them with a mandibular overdenture. A total of 11 ramus frames were removed at 19 to 109 months post-treatment, mostly due to supramucosal bar fracture (N = 6) or mobility (N = 3). Kaplan-Meier product-limit analysis revealed the post-treatment survival probability for functional ramus frame implants to be 99.3% at 2 years (266 patients), 98.9% at 3 years (223 patients), 97.9% at 4 years (198 patients), 96.9% at 5 years (160 patients), 96.9% at 6 years (123 patients), 95.0% at 7 years (86 patients), 95.0% at 8 years (67 patients), 93.3% at 9 years (43 patients), and 91.1% at 10 years (25 patients). No statistically significant differences in functional ramus frame implant survival were found relative to patient gender, smoking, presence of natural maxillary teeth, or compliance with semi-annual maintenance care. Fracture of endosseous anterior feet/posterior arms was the most frequent implant-related complication on 29 implants, which were left in place, repaired, or replaced in situ without implant removal. At 5 years, the ramus frame implant functional survival probability without any implant-related biological or mechanical complication was 88.9%. Ramus frame dental implants, immediately loaded with a fully implant-borne mandibular overdenture, exhibited a high degree of long-term functional survival and safety in severely atrophic edentulous human mandibles.

AbstractObjectivesPeriodontal inflammation may be assessed by bleeding on probing and subgingival temperature. This pilot study evaluated the intrapatient relationship between subgingival temperature and selected bacterial groups/species in deep periodontal pockets with bleeding on probing.Materials and MethodsIn each of eight adults, an electronic temperature probe identified three “hot” pockets with elevated subgingival temperature and three “cool” pockets with normal subgingival temperature among premolars/molars with 6‒10 mm probing depths and bleeding on probing. Microbial samples collected separately from the hot and cool periodontal pockets were cultured for selected periodontal pathogens.ResultsHot compared to cool periodontal pockets revealed significantly higher absolute and normalized subgingival temperatures and yielded higher mean proportions of Porphyromonas gingivalis (10.2% for hot vs. 2.5% for cool, p = 0.030) and total red/orange complex periodontal pathogens (48.0% for hot vs. 24.6% for cool, p = 0.012).ConclusionsHot versus cool deep periodontal pockets harbored significantly higher levels of major periodontal pathogens. Subgingival temperature measurements may potentially be useful to assess risk of periodontitis progression and the efficacy of periodontal therapy.

AIM This study compared two molecular iodine mouthrinses for their in vitro bactericidal effects against subgingival biofilm bacteria from severe periodontitis patients. MATERIALS AND METHODS In a subgingival biofilm eradication assay, dilution aliquots of subgingival microbial specimens from 32 adults with severe periodontitis were mixed in vitro with either a mouthrinse containing 100 parts per million (ppm) molecular iodine (Iorinse®) or one containing 150 ppm molecular iodine (iClean®), followed by mouthrinse neutralization after 60 seconds with 3% sodium thiosulfate. The mixtures, along with unexposed subgingival biofilm aliquots, were inoculated onto enriched Brucella blood agar and incubated anaerobically for 7 days to quantitate total viable bacterial counts and selected red/orange complex periodontal pathogens (Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia/nigrescens, Parvimonas micra, Campylobacter rectus, and Fusobacterium nucleatum). RESULTS Both molecular iodine mouthrinses significantly reduced total viable bacterial counts in the subgingival biofilm samples, with iClean® providing significantly greater in vitro suppression than Iorinse®. Both molecular iodine mouthrinses also significantly reduced total red/orange complex periodontal pathogens, with significantly greater suppression also exhibited by iClean®. CONCLUSION The molecular iodine mouthrinses exerted marked bactericidal activity in vitro against human subgingival biofilm microbial species, including red/orange complex periodontal pathogens associated with severe periodontitis, with iClean® providing significantly better antimicrobial activity than Iorinse®. CLINICAL SIGNIFICANCE These findings suggest potential value of molecular iodine mouthrinses in the treatment and prevention of periodontal diseases.

Antibiotic resistance patterns of the major human periodontal pathogen Porphyromonas gingivalis were assessed over a 20-year period in the United States. Subgingival P. gingivalis was cultured pre-treatment from 2193 severe periodontitis patients during three time periods: 1999–2000 (936 patients), 2009–2010 (685 patients), and 2019–2020 (572 patients). The clinical isolates were tested for in vitro resistance to 4 mg/L for clindamycin and doxycycline, 8 mg/L for amoxicillin, and 16 mg/L for metronidazole, with a post hoc combination of data for metronidazole plus amoxicillin. Clindamycin-resistant P. gingivalis was significantly more prevalent in 2009–2010 (9.1% of patients) and 2019–2020 (9.3%; 15-fold increase) as compared to 1999–2000 (0.6%). P. gingivalis resistance to amoxicillin also significantly increased from 0.1% of patients in 1999–2000 to 1.3% in 2009–2010 and 2.8% (28-fold increase) in 2019–2020. P. gingivalis resistance to metronidazole, metronidazole plus amoxicillin, and doxycycline was low (≤0.5% prevalence), and statistically unchanged, over the 20-year period. These findings are the first to reveal marked increases over 20 years in clindamycin-resistant and amoxicillin-resistant P. gingivalis in United States periodontitis patients. Increased antibiotic resistance of P. gingivalis and other periodontitis-associated bacteria threatens the efficacy of periodontal antimicrobial chemotherapy.

Background:Supragingival air polishing of teeth effectively removes dental plaque and extrinsic stain on coronal tooth surfaces, but its impact on specific periodontal pathogens in adjacent subgingival biofilms is not known. This study assessed the microbiological effect of supragingival air polishing on the subgingival microbiota of individuals with severe periodontitis.Methods:Supragingival air polishing with a sodium bicarbonatebased powder was performed on 15 adult test subjects, with the nozzle of the air polishing device aimed apically at a 45° angle onto tooth surfaces immediately coronal to the entrance of periodontal pockets. Supragingival prophylaxis paste polishing, using a slow-speed handpiece, was carried out on 13 adult control subjects. Subgingival specimens were collected from a single 5 mm to 7 mm periodontal pocket with bleeding on probing in each of the study participants before and immediately after supragingival polishing procedures. Viable bacterial counts and selected putative periodontal pathogens (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia/nigrescens, Fusobacterium nucleatum, Parvimonas micra, Campylobacter species) were quantified by microbial culture, and motile morphotypes (spirochetes and motile rods) by phase-contrast microscopy.Results:Statistically significant decreases were detected after supragingival air polishing in total viable counts (84.9% decrease), in P. intermedia/nigrescens, F. nucleatum, Campylobacter species, total proportions of red/orange complex periodontal pathogens (82.3% decrease), and in motile morphotypes (85.3% decrease). No statistically significant subgingival microbiological changes occurred with supragingival prophylaxis paste polishing.Conclusion:Supragingival air polishing of teeth, but not supragingival prophylaxis paste polishing, may serve as a useful therapeutic adjunct to disrupt and help remove pathogenic biofilms in deep periodontal pockets.

This study evaluated a combined systemic and topical anti-infective periodontal treatment of 35 adults who had experienced ongoing periodontal breakdown following conventional surgical periodontics. The prescribed anti-infective therapy, based on microbiological testing, consisted of a single course of metronidazole plus ciprofloxacin (23 patients), metronidazole plus amoxicillin/clavulanic acid (10 patients), and metronidazole plus ciprofloxacin followed by metronidazole plus amoxicillin/clavulanic acid (2 patients). In addition, the study patients received 0.1% povidone-iodine subgingival disinfection during non-surgical root debridement and daily patient administered oral irrigation with 0.1% sodium hypochlorite. At 1 and 5 years post-treatment, all study patients showed gains in clinical periodontal attachment with no further attachment loss, and significant decreases in pocket probing depth, bleeding on probing, and subgingival temperature. The greatest disease resolution occurred in patients who at baseline harbored predominantly major periodontal pathogens which post-antibiotics became non-detectable and substituted by non-periodontopathic viridans streptococci. The personalized and minimally invasive anti-infective treatment regimen described here controlled periodontitis disease activity and markedly improved the clinical and microbiological status of the refractory periodontitis patients.

Dr. Benjamin Franklin Hammond, Professor Emeritus of Microbiology, School of Dental Medicine, University of Pennsylvania; Professor of Medicine and Oral Microbiology (retired), Medical College of Pennsylvania (now Drexel College of Medicine); Research Professor of Periodontology, Kornberg School of Dentistry, Temple University (retired); and seventh president of the American Association for Dental Research (AADR 1978–1979), died on May 14, 2022, at the age of 88. For all who knew Benjamin Franklin Hammond, the word cultured would be recognized as a description that neatly fit the man. Cultured described both what he did and what he was: as a preeminent microbiologist of the oral cavity, Ben grew (cultured) and studied numerous microbial life forms inhabiting that ecological niche. His work added to our understanding of the complex microbial milieu inhabiting the oral cavity and how different members of this population might contribute to the development and progression of oral diseases. His contribution to the field of oral microbiology included an extensive publication of articles in professional, peer-reviewed publications. As much as he was an accomplished scientist and teacher, Ben also equally had an extensive knowledge and appreciation of the arts and humanities. His cultural interests and expertise were wide and eclectic, ranging from an expert knowledge of early American painting to a thorough appreciation of classical opera. In fact, Ben often took advantage of the proximity of his home in Philadelphia to New York to attend the Metropolitan Opera, which he adored. A visit to his office in the Department of Microbiology of the University of Pennsylvania’s School of Dental Medicine would disclose a bust of the soprano, Joan Sutherland, ensconced on his desk. He once remarked something to the effect that, “As long as you see Joan here, you know that I am still around!” From the piano that he loved playing, to the French that he enjoyed speaking (fluently), Ben was indeed a multifaceted renaissance man of culture. As a patron of the arts, Ben supported several regional cultural institutions, including the Philadelphia Museum of Art and the Brandywine Conservancy and Museum of Art, where he was a trustee. Ben Hammond’s story is one of accomplishment and prevailing over obstacles. It begins just outside of Austin, Texas, on February 28, 1934, when he was born to Dr. Virgil Thomas Hammond and Helen Marguerite Smith. From his mother, an accomplished pianist, Ben inherited a love and appreciation of music and art that would remain with him throughout his life. There is an anecdote that later in life, when undertaking a 1-year sabbatical at the Forsyth Dental Institute in Boston, he insisted on taking his beloved piano with him from his home in Philadelphia. This necessitated hauling it up, through a secondfloor window, in order to install it into his Boston apartment. As the son of a successful dentist and a cousin to a number of physicians, Ben’s lifelong love of learning and interest in science and oral health care was kindled from an early age. This led him to a Bachelor of Arts at the University of Kansas in 1954 and a DDS from Meharry Medical College in 1958. After graduating with his dental degree in 1958 and discovering that clinical dental practice was not for him, Ben accepted a faculty position in the Department of Microbiology of the University of Pennsylvania’s School of Dental Medicine, which was 1149964 JDRXXX10.1177/00220345221149964Journal of Dental ResearchBen Hammond research-article2023

An adult periodontitis patient treated with mechanical/surgical therapy experienced gingival necrosis and granulomas post-treatment. Aggregatibacter actinomycetemcomitans, a tissue-invasive pathogen, was recovered and multidrug-resistant but susceptible to ciprofloxacin. Systemic ciprofloxacin eliminated A. actinomycetemcomitans with marked clinical improvement. Ciprofloxacin may be prescribed for A. actinomycetemcomitans periodontal infection unresponsive to the common amoxicillin-metronidazole treatment.

Localized juvenile (aggressive) periodontitis starts at puberty in otherwise healthy individuals and involves the proximal surfaces of permanent incisors and first molars. The disease destroys a sizeable amount of periodontal bone within a few months despite minimal dental plaque and gingival tissue inflammation. Cytomegalovirus and Epstein-Barr virus, as well as the two main periodontopathic bacteria Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis, are linked to juvenile periodontitis. Juvenile periodontitis-affected teeth show cementum hypoplasia. We hypothesize that an active herpesvirus infection, at the time of root formation, hampers cementum formation and, at puberty, herpesvirus reactivation triggers an upgrowth of bacterial pathogens which produce rapid periodontal destruction on teeth with a defective periodontium. A pathogenic interaction between active herpesviruses and bacterial pathogens can potentially explain the etiology and incisor-first molar destructive pattern of juvenile periodontitis. Effective treatment of juvenile periodontitis may target the herpesvirus-bacteria co-infection.

BACKGROUND This study determined the prevalence of aggressive (molar-incisor pattern) (Ag/MI) periodontitis and assessed the associated subgingival bacterial-herpesvirus microbiota in Pueblo Indian adolescents in the southwestern United States. METHODS The study included 240 Pueblo Indian adolescents, aged 13-20 years old, residing in three Rio Grande River villages in New Mexico and the Hopi Pueblo reservation in Arizona. Adolescents with Ag/MI periodontitis or periodontal health provided subgingival samples for culture of bacterial pathogens and for polymerase chain reaction detection of periodontal herpesviruses. RESULTS Ag/MI periodontitis was detected in 22 (9.2%) Pueblo Indian adolescents, with 21 exhibiting a localized molar-incisor breakdown pattern. Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and other red/orange complex bacterial pathogens predominated in Ag/MI periodontitis, whereas periodontal health yielded mainly viridans streptococci and Actinomyces species. Periodontal herpesviruses demonstrated a 3.5 odds ratio relationship with Ag/MI periodontitis. The only adolescent with generalized Ag/MI periodontitis harbored viral co-infection by cytomegalovirus plus Epstein-Barr virus Type 1, in addition to A. actinomycetemcomitans, P. gingivalis, and several other periodontopathic bacteria. CONCLUSIONS Pueblo Indian adolescents showed an unusually high prevalence of early-age Ag/MI periodontitis predominated by periodontopathic bacteria and herpesviruses suspected to be major etiologic agents of the disease.

Background:Clinical standardization and calibration training is recommended to increase the reproducibility of periodontal probing, but its impact on manual periodontal probing outcomes has received little attention. This study examined the reproducibility of manual periodontal probing performed by a periodontist after completion of a comprehensive standardization and calibration training program.Methods:A newly-educated periodontist was subjected to an individualized periodontal probing standardization and calibration training program involving approximately 24 total hours of lecture, bench-top, and clinical instruction/evaluation. Satisfactory completion of each portion of the training program required ≥ 95% intra-examiner agreement within 1 mm between initial and repeat measurements, and a ≥ 90% level of exact agreement with measurements by a "gold standard" examiner. The periodontist then evaluated bleeding on probing (BOP) and performed duplicate measurements of probing depth (PD) and the distance between the cementoenamel junction and gingival margin (CEJ-GM) with a manual periodontal probe on 567 periodontal sites exhibiting ≥ 5 mm PD with BOP in 39 adults. Clinical periodontal attachment level (CAL) was calculated for each site as (PD) - (CEJ-GM).Results:Intra-examiner measurement error (the standard deviation for a single measurement) was found to be 0.21 mm for PD, 0.15 mm for CEJ-GM, and 0.26 mm for CAL. Replicate assessments of PD and CAL yielded excellent exact agreement kappa scores of 0.86 and 0.87, respectively. Greater intra-examiner measurement error was found at periodontal sites with more gingival inflammation as measured by higher BOP index scores.Conclusion:These findings demonstrate that a rigorous periodontal probing standardization and calibration training program facilitates acquisition of highly reproducible PD and CAL assessments in moderate to deep inflamed periodontal pockets with a manual periodontal probe. Similar formal hands-on training should be incorporated into dental education programs and clinical research studies to improve the diagnostic performance of manual periodontal probing of the periodontium.

PURPOSE:This pilot study assessed the immediate in vivo effect of high peak pulse power neodymium-doped yttrium aluminum garnet (Nd:YAG) laser monotherapy on selected red/orange complex periodontal pathogens in deep human periodontal pockets. METHODS:Twelve adults with severe periodontitis were treated with the Laser-Assisted New Attachment Procedure (LANAP®) surgical protocol, wherein a free-running, digitally pulsed, Nd:YAG dental laser was used as the initial therapeutic step before mechanical root debridement. Using a flexible optical fiber in a handpiece, Nd:YAG laser energy, at a density of 196 J/cm² and a high peak pulse power of 1,333 W/pulse, was directed parallel to untreated tooth root surfaces in sequential coronal-apical passes to clinical periodontal probing depths, for a total applied energy dose of approximately 8-12 joules per millimeter of periodontal probing depth at each periodontal site. Subgingival biofilm specimens were collected from each patient before and immediately after Nd:YAG laser monotherapy from periodontal pockets exhibiting ≥6 mm probing depths and bleeding on probing. Selected red/orange complex periodontal pathogens (Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia/nigrescens, Fusobacterium nucleatum, Parvimonas micra, and Campylobacter species) were quantified in the subgingival samples using established anaerobic culture techniques. RESULTS:All immediate post-treatment subgingival biofilm specimens continued to yield microbial growth after Nd:YAG laser monotherapy. The mean levels of total cultivable red/orange complex periodontal pathogens per patient significantly decreased from 12.0% pre-treatment to 4.9% (a 59.2% decrease) immediately after Nd:YAG laser monotherapy, with 3 (25%) patients rendered culture-negative for all evaluated red/orange complex periodontal pathogens. CONCLUSIONS:High peak pulse power Nd:YAG laser monotherapy, used as the initial step in the LANAP® surgical protocol on mature subgingival biofilms, immediately induced significant reductions of nearly 60% in the mean total cultivable red/orange complex periodontal pathogen proportions per patient prior to mechanical root instrumentation and the rest of the LANAP® surgical protocol.

AIM:This study evaluated the reliability of a new rapid biological spore test (BST) for determining the sterilization efficacy of dental steam autoclaves within 20 minutes, as compared to a conventional BST requiring 2 days of incubation after autoclave exposure.MATERIALS AND METHODS:A total of 177 pairs of BST, each composed of a rapid test (Celerity™ 20 Steam Biologic Indicator, Steris) and a conventional BST (Attest™ 1262 Biological Indicator, 3M), both containing Geobacillus stearothermophilus spores, were placed into steam autoclaves loaded with instruments, and subjected to either sterilizing (157 pairs) or non-sterilizing conditions (20 pairs). Celerity™ BST was then incubated for 20 minutes at 57°C, with the growth medium evaluated spectrophotometrically for fluorescent α-glucosidase signal changes (no change with successful sterilization; increased fluorescence after failed sterilization). Attest™ BST was incubated for 48 hours at 57°C, after which a pH-based color change in the culture broth was visually assessed (no change in purple color with successful sterilization; change to yellow color with failed sterilization).RESULTS:Celerity™ and Attest™ BST both accurately identified successful sterilization, with no G. stearothermophilus spore growth from either BST after exposure to sterilizing steam autoclave conditions (100% agreement between 157 pairs of each BST). Both BST also accurately detected unsuccessful sterilization, with all tested ampoules positive for G. stearothermophilus spore germination after non-sterilizing steam autoclave time periods. Both BST exhibited 100% sensitivity, specificity, and accuracy for detection of sterilizing steam autoclave conditions.CONCLUSION:Celerity™ BST, after only 20 minutes incubation, performed equally as well as a BST requiring 48 hours incubation in determining the sterilization efficacy of dental steam autoclaves.CLINICAL SIGNIFICANCE:Rapid BST offer earlier detection of sterilization failure before potentially contaminated dental instruments are used in clinical patient care.

AIM The World Health Organization (WHO) periodontal probe is recommended for epidemiologic surveys and periodontal screening, but its ability to identify subgingival dental calculus (DC) relative to a #11/12 explorer is not known. This study compared in vitro the ability of the WHO probe and a #11/12 explorer to detect subgingival DC. MATERIALS AND METHODS Three typodont models with randomly distributed artificial DC on mandibular molar and premolar root surfaces were assessed with a WHO periodontal probe and a #11/12 explorer by two periodontists. The diagnostic performance of the two instruments for subgingival DC detection was compared using 2 × 2 contingency table analysis. RESULTS A #11/12 explorer provided better reproducibility, a higher level of sensitivity, higher positive predictive values, higher negative predictive values, and greater overall accuracy (diagnostic effectiveness) (76.9% vs. 68.5% for the first periodontist; 87.0% vs. 75.0% for the second periodontist) for detection of subgingival DC than the WHO probe. CONCLUSION The in vitro diagnostic performance of a #11/12 explorer was superior to the WHO periodontal probe for identification of subgingival DC. CLINICAL SIGNIFICANCE A #11/12 explorer, rather than the WHO probe, is recommended for identification of subgingival DC.

Changes were evaluated over 10 years in the in vitro resistance of human periodontopathic strains of Parvimonas micra to four antibiotics. Subgingival biofilms culture positive for P. micra from 300 United States adults with severe periodontitis in 2006, and from a similar group of 300 patients in 2016, were plated onto anaerobically incubated enriched Brucella blood agar alone, or supplemented with either doxycycline (4 mg/L), clindamycin (4 mg/L), amoxicillin (8 mg/L), or metronidazole (16 mg/L). P. micra growth on antibiotic-supplemented media indicated in vitro resistance to the evaluated antibiotic concentration. P. micra resistance was significantly more frequent among patients in 2016, as compared to 2006, for doxycycline (11.3% vs. 0.3% patients; 37.7-fold increase), and clindamycin (47.3% vs. 2.0% patients; 23.7-fold increase) (both p < 0.001), whereas resistance to amoxicillin (2.3% vs. 1.0% patients) and metronidazole (0% vs. 0.3% patients) remained low and statistically unchanged between the two patient groups (p-values > 0.05). No P. micra isolates in 2006 or 2016 were jointly resistant in vitro to both amoxicillin and metronidazole. The alarming increases in subgingival P. micra resistance to doxycycline and clindamycin raise serious questions about the empiric use of these antibiotics, either locally or systemically, in the treatment of United States periodontitis patients harboring subgingival P. micra.

Silver diamine fluoride (SDF) has been used in management of dentinal hypersensitivity and dental caries. This in vitro study evaluated the antimicrobial effects of SDF on subgingival microorganisms from severe human periodontitis lesions. Subgingival biofilm specimens from 24 adults with severe periodontitis were mixed in vitro with 19% or 38% SDF or left untreated (n = 24 per group) and then inoculated on enriched Brucella blood agar with anaerobic incubation. Selected red- and orange-complex periodontal pathogens were phenotypically identified in the subgingival specimens, including Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia/nigrescens, Parvimonas micra, Campylobacter rectus, Fusobacterium nucleatum, and Streptococcus constellatus. Other microbial species recovered from SDF-treated specimens were identified using matrix-assisted laser desorption- ionization time-of-flight mass spectrometry. The SDF-treated specimens yielded significantly lower mean total viable counts and significantly lower mean total cultivable proportional levels of red- and orange-complex periodontal pathogens (0.5%-0.6%) than did untreated specimens (25.9%) (P < 0.001). The only red- and orange-complex species recovered from SDF-treated specimens were P micra (3 patients) and S constellatus (1 patient). The predominant cultivable isolates from SDF-treated specimens were Streptococcus oralis and other streptococci of relatively low periodontopathic and cariogenic potential. No statistically significant in vitro antimicrobial differences were found between 19% and 38% SDF against subgingival biofilm specimens. In this experiment, SDF exhibited substantial in vitro antimicrobial activity against putative periodontal pathogens from severe periodontitis lesions. The suppression of red- and orange-complex periodontal pathogens in subgingival biofilms by SDF treatment, along with the selection of SDF-resistant Streptococcus species that are associated with periodontal health, suggests a potential new therapeutic use for SDF in the management of human periodontal infections.