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Tropical river deltas, and the social-ecological systems they sustain, are changing rapidly due to anthropogenic activity and climatic change. Baseline data to inform sustainable management options for resilient deltas is urgently needed and palaeolimnology (reconstructing past conditions from lake or wetland deposits) can provide crucial long-term perspectives needed to identify drivers and rates of change. We review how palaeolimnology can be a valuable tool for resource managers using three current issues facing tropical delta regions: hydrology and sediment supply, salinisation and nutrient pollution. The unique ability of palaeolimnological methods to untangle multiple stressors is also discussed. We demonstrate how palaeolimnology has been used to understand each of these issues, in other aquatic environments, to be incorporated into policy. Palaeolimnology is a key tool to understanding how anthropogenic influences interact with other environmental stressors, providing policymakers and resource managers with a 'big picture' view and possible holistic solutions that can be implemented., Competing Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2023.)

Cuspal fractures are relatively common. Fortunately for esthetics, when a cuspal fracture occurs in a maxillary premolar, it most commonly involves the palatal cusp. Fractures with a favorable prognosis may be approached with a minimally invasive treatment to successfully retain the natural tooth. This report describes 3 cases of "cuspidization" to treat maxillary premolars with cuspal fractures. After identifying a palatal cusp fracture, the fractured segment was removed, resulting in a tooth that closely resembles a cuspid. Depending on the extent and location of the fracture, root canal treatment was indicated. Subsequently, conservative restorations sealed the access and covered exposed dentin. Full coverage restorations were neither required nor indicated. The resulting treatment provided practical and functional treatment with a good esthetic outcome. When indicated, the described cuspidization technique can conservatively manage patients with subgingival cuspal fractures. The procedure is minimally invasive and cost-effective and can be done conveniently in routine practice., (Copyright © 2023 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Dramatic declines in diurnal pollinators have created great scientific interest in plant-pollinator relationships and associated pollination services. Existing literature, however, is generally focused on diurnal pollinating insect taxa, especially on Apidae (Hymenoptera) and Syrphidae (Diptera) pollinators, while nocturnal macro-moths that comprise extremely species-rich flower-visiting families have been largely neglected. Here, we report that in agricultural landscapes, macro-moths can provide unique, highly complex pollen transport links, making them vital components of overall wild plant-pollinator networks in agro-ecosystems. Pollen transport occurred more frequently on the moths' ventral thorax rather than on their mouthparts that have been traditionally targeted for pollen swabbing. Pollen transport loads suggest that nocturnal moths contribute key pollination services for several wild plant families in agricultural landscapes, in addition to providing functional resilience to diurnal networks. Severe declines in richness and abundance of settling moth populations highlight the urgent need to include them in future management and conservation strategies within agricultural landscapes.

Background: Vertical root fracture (VRF) requires root removal. Diagnostics for proper identification are critical. The author conducted a study to relate subjective, objective, and radiographic findings for VRF identification. They noted visual changes of root and overlying bone patterns after flap reflection., Methods: The author examined a case series of roots with suspected VRF after flap reflection and root or root-end removal; 42 roots were identified with a fracture. Before reflection, the author obtained diagnostic and periapical radiographic data that included symptoms, soft-tissue changes, percussion, mobility, probing patterns, and radiographic findings. After flap reflection, the author evaluated bony changes and root surfaces. VRF was visually confirmed after tooth or root removal., Results: Signs and symptoms diagnostic of VRF were inconsistent. All patients had endodontic therapy, many with posts, and for all patients, the pain was none to mild. In addition, the author found a history or presence of swelling (77%) or sinus tract (31%), that probing patterns differed (narrow-rectangular 66%), and that there was no defect in some patients (21%). Radiographic patterns varied from no change to extensive bone loss, and mobility ranged from none (55%) to slight or moderate (45%). Flap reflection revealed a "punched-out" bony lesion with granulomatous tissue (100%), and patterns were fenestration (21%) or dehiscence (79%). A fracture was visible on roots or resected root ends., Conclusions: The author found no consistent signs, symptoms, or radiographic changes of VRF. Flap reflection was found to be predictably useful; fractured roots had bony defects filled with granulomatous tissue., Practical Implications: VRF may be suspected from clinical findings; however, flap reflection is usually required for identification. Characteristic bony pattern and root visualization reveals the fracture, although root-end resection and examination is occasionally required., (Copyright © 2017 American Dental Association. Published by Elsevier Inc. All rights reserved.)

Objectives: Condensing osteitis is a radiographic finding, but with no reported histologic investigations in humans. The objectives of this study were to evaluate and describe histologically condensing osteitis in human cadaver jaws. Patterns of bone formation and presence/absence and nature of inflammation were examined., Methods: Specimens of mandibles and maxillas were obtained from cadavers and examined radiographically. Those periapical areas with characteristics of condensing osteitis were removed en bloc, decalcified, and processed for light microscopy. For comparison, specimens that showed normal apical radiographic anatomy were also removed for examination., Results: Normal apical regions showed an intact periodontal ligament and a thin layer of alveolar bone proper surrounded by cancellous bone with fatty marrow. In contrast, areas of condensing osteitis exhibited areas of inflammation or no inflammation, occupied by connective tissue. This area was bordered by a rim of varying widths of dense lamellar-type bone replacing the cancellous bone and marrow., Conclusions: The histologic changes of condensing osteitis consisted of the replacement of cancellous bone with compact bone. Areas of fibrosis and an inflammatory infiltrate were seen in some but not all specimens. All teeth exhibiting condensing osteitis had an identifiable etiology that likely resulted in degenerative pulp disease., (Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Outcomes encompass multiple factors, not just success and failure. They include other considerations such as being workable and profitable to the dentist and safe and acceptable to the patient. The more biological outcomes are most frequently measured. These measurements are on a scale from least to most predictable outcomes of treatment by the dentist, as shown on the evidence pyramid. Impact trauma is an example of a general scarcity of high-level evidence with treatment because of the nature and individuality of the injuries and the difficulty (or impossibility) of designing controlled clinical trials in humans. Much of the evidence is cohort (retrospective or observational studies), case reports, animal studies, and "expert" opinion. Thus, guidelines are largely based on lower levels of evidence. Nonetheless, the current guidelines provide the clinician with the best evidence that is available. The best opportunity for randomized controlled trials is in prevention. Specifically, mouthguard design and usage can be subjected to higher levels of controlled research. Revitalization and regeneration are relatively new procedures. To date, there is a lack of high levels of evidence to be able to substantiate whether these are clinically feasible to become a routine in practice., (Copyright © 2013. Published by Elsevier Inc.)

Introduction: Patient preferences should be taken into account by clinicians when treatment planning. The purposes of this study were to describe the number of visits patients preferred when undergoing root canal therapy (RCT) and to assess whether their preferences were related to hypothetical treatment success rates., Methods: Self-administered questionnaires were mailed to 351 consecutive patients scheduled for initial RCT appointments in the University of Iowa College of Dentistry's graduate or faculty endodontic clinic. The questionnaires ascertained demographic information; preferences for 1-visit versus 2-visit RCT given different hypothetical success rate scenarios for the 2 approaches, as well as patient dental history. Univariate frequency distributions were generated, and relationships between hypothetical success rates and patient preferences were evaluated., Results: Questionnaires were returned by 124 patients (35% response). Given equal success rates, 78% of respondents preferred 1-visit RCT, compared with 7% who preferred 2-visit RCT and 16% who would follow their dentist's recommendation. As success rates for 2-visit RCT went from equal to 5% better to 10% better to 20% better compared with 1-visit RCT, the proportion of respondents who preferred 2-visit RCT increased from 7% to 34% to 46% to 65%, respectively. Regardless of success rates, approximately 5% of respondents said they would prefer 2-visit RCT, and 20% would do whatever their dentist recommended., Conclusions: Although most respondents preferred 1-visit RCT regardless of success rates, many would prefer 2-visit RCT if its success rate were greater than that of 1-visit RCT. This finding confirms the importance of discussing success rates and considering patients' wishes when treatment planning., (Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Since the "greatest generation" is rapidly passing from the scene, this article maintains that the time is ripe for the oral history community to engage in a serious examination of the strengths and weaknesses of World War II veteran interviews. Using a small case study about the battle of Okinawa (April-June 1945), the essay examines some aspects of the memory quality of World War II veterans interviewed late in life. It presents three arguments. First, American veterans of World War II were frequently reticent about recounting their memories. They often waited until late in life to do so. Second, the American World War II veterans' interviews were generally reliable and accurate even when given late in life. Nonetheless, some problems were encountered in interviewing veterans long after a battle. Third, the veterans could provide greater detail about their initial experiences during a campaign. Recollections about their later experiences during the same campaign were foggier. The author concedes, however, that the small size of his case study means that the conclusions can only have validity if confirmed by the experience of other oral history interviewers. Hence the author's goal is to initiate this important conversation rather than to conclude it.

Introduction: The purpose of this in-depth investigation was to identify, clarify, and substantiate clinical terminology relative to apical/periapical/periradicular diagnostic states, which is used routinely in the provision of endodontic care. Furthermore, the information gleaned from this investigation was used to link diagnostic categories to symptoms, pathogenesis, treatment, and prognosis wherever possible, along with establishing the basis for the metrics used in this diagnostic process., Materials and Methods: Diagnostic terminologies and their relevance to clinical situations were procured from extensive historic and electronic searches and correlated with contemporary concepts in disease processes, clinical assessments, histologic findings (if appropriate), and standardized definitions that have been promulgated and promoted for use in the last 25 years in educational programs and test constructions and for third-party concerns., Results: In general, clinical terminology that is used routinely in the practice of endodontics is not based on the findings of scientific investigations. The diagnostic terms are based on assumptions by correlating certain signs, symptoms, and radiographic findings with what is presumed (not proven) to be the underlying disease process of a given clinical state. There were no studies that specifically tried to assess the accuracy of the metrics used contemporarily for the classification of clinical disease states., Conclusion: A succinct diagnostic scheme that could be described thoroughly, agreed on unanimously, coded succinctly for easy electronic input, and ultimately used for follow-up analysis would not only drive treatment modalities more accurately, but would also allow for future outcomes assessment and validation.

Objective: This study evaluated the ability of a resin-based system (Resilon/Epiphany) and gutta-percha/sealer with warm vertical or cold lateral compaction to prevent coronal leakage., Study Design: A polymicrobial suspension in a dual-chamber model was used. Seventy extracted maxillary incisors were prepared, divided into 4 groups, and obturated: Group 1, lateral compaction/gutta-percha/AH Plus; Group 2, lateral compaction/Resilon; Group 3, continuous wave compaction/gutta-percha/AH Plus; Group 4, continuous wave compaction/Resilon. Upper chambers held a mixed suspension of endodontic pathogens. Apices were suspended in the lower chambers. Leakage was determined daily for 40 days and evaluated for turbidity. Data were analyzed using survival analysis; log-rank test was used to analyze differences in time to leakage., Results: Median time to leakage: 16, 15, 11, and 25 days for Groups 1 to 4 respectively (P = .93, log-rank test)., Conclusion: No difference in time to leakage among the 4 treatment groups existed.

Vital signs aid in assessing patient health and the disease severity. The objectives of this study were to determine changes in vital signs of patients with pulpal necrosis (PN) and acute apical abscess (AAA). The vital signs measured at the emergency visit were blood pressure, heart rate, temperature, and lymphadenopathy. Visual analogue scales (VASs) were used to assess (1) pain and (2) malaise. Emergency treatment was rendered. At a subsequent (baseline) visit and with clinical symptoms resolved, systemic vital sign measurements and VASs were repeated. The presence or absence of swelling with vital signs and VASs of pain and swelling were compared. Compared with baseline, data showed no marked elevation in temperature, blood pressure, or lymphadenopathy, regardless of presence or absence of swelling. VAS measurements of pain and malaise did show statistically significant higher numbers at the emergency appointment, indicating a difference from baseline. Swelling versus no swelling did not differ. Vital signs were not impacted by localized AAA, although pain and malaise were greater. Vital signs might not be useful determinants of treatment or pharmacotherapeutic measures with localized AAA.

Objective: The aim of this study was to determine the distribution patterns of sealer relative to the gutta-percha and the canal wall following the use of different obturation techniques: vertical condensation, Obtura II, System B, SimpliFill, and Thermafil Plus; lateral condensation was used as a comparison., Methods and Materials: One hundred five extracted single-rooted teeth were divided into 5 groups of 20 according to obturation technique, with 5 in the lateral condensation group. Instrumentation technique and sealer selection were based on the manufacturer's recommendations. Following obturation, teeth were stored for 4 months at 37 degrees C in 100% humidity. Roots were split longitudinally and halves were examined under a stereomicroscope (x 10) to determine the amount of sealer coverage between the gutta-percha and canal wall. Coverage was categorized as slight (0 to 1/3), low partial (1/3 to 2/3), high partial (2/3 to 9/10), and complete (9/10 to 10/10)., Results: Different techniques showed different patterns, but no obturation technique had sealer forming a continuous layer between the gutta-percha and canal wall. The vertical condensation group generally had low partial coverage. Obtura II was the only group to have slight coverage, which occurred in the coronal half. Coronal and apical halves in both the System B and Thermafil Plus groups had the most samples with high partial coverage. SimpliFill had the most samples with complete coverage in both the coronal and the apical portions. All lateral condensation samples showed low partial coverage., Conclusion: Sealer distribution patterns were incomplete and inconsistent, regardless of the obturation technique. No technique had sealer forming a continuous layer between the gutta-percha and canal wall.

Endotoxin, elaborated by gram-negative organisms, is an important factor in apical periodontitis. The objective of this study was to evaluate the magnitude of endotoxin penetration through root canal treated teeth using a dual chamber model system. Forty-four maxillary anterior teeth were prepared endodontically and canals filled either by lateral condensation or a warm thermoplasticized technique in combination with either Roth's 801 or AH 26 sealer. Teeth were suspended in the model system with a mixed anaerobic bacterial suspension in the upper chamber and HBSS in the lower chamber. The QCL-1000 LAL assay was used to measure endotoxin at 0, 1, 7, 14, and 21 days. Response feature analysis using trapezoidal area under the curve was performed; the four treatment groups were compared using nonparametric methods. Groups differed (p = 0.028), with thermoplasticized root canal filling/Roth's 801 sealer permitting the least apical endotoxin penetration. Results suggest that Roth's 801 sealer may have a role in inhibiting endotoxin penetration.

The purpose was to aid in determining termination of instrumentation and obturation. A meta-analysis was conducted as to success/failure of different obturation lengths. Inclusion criteria were (a) minimum follow-up of 2 yr, (b) data on obturation length, (c) definition of success/failure, (d) available data on success/failure, (e) radiographic evaluation. Correlations were made as to success/failure as related to length of obturation from the apex. When comparing group A (obturated 0-1 mm from apex) versus group C (obturated past apex) using the DerSimonian and Laird estimates, group A showed a marginally better (p < 0.10) success rate than group C by 28.8%. Group A had better success than group B (obturated >1 mm short); the difference was insignificant. The results were similar after controlling for study quality using a single random effects regression model. In conclusion, the meta-analysis indicated that a better success rate is achieved when treatment includes obturation short of the apex.

The objective of this study was to describe the incidence, type, risk factors, and sequelae of fractures experienced by community-dwelling elderly Canadians. Data are from the Canadian Study of Health and Aging (CSHA), a longitudinal cohort study, collected in three waves: baseline (1991), wave 2 (1996), and wave 3 (2001). In CSHA-2 (1996), fractures were reported by 3.7 per cent of men and 7.5 per cent of women; in CSHA-3 (2001), by 2.9 per cent of men and 7.3 per cent of women. The distribution of fracture types was similar for men and women. Risk factors for women were increased age, history of fracture, and regular alcohol use; for men, stroke, arthritis, and lack of independent bathing. Walkers or wheelchairs were needed by over 30 per cent of those with any lower body fracture. One third of subjects with any fracture and over 50 per cent with femur fractures reported moderate or severe pain. It is concluded that elderly Canadians are at high risk for fractures, and older women are at most risk. Pain and mobility problems were common sequelae. The need for primary and secondary prevention of these age-related events is paramount.

The purpose of this study was to examine coverage patterns of sealer on canal walls and between gutta-percha cones after lateral condensation. Ninety extracted teeth with single canals were evenly and randomly divided into three sealer groups (Roth's, Sealapex, AH 26). Canals were cleaned and shaped, then coated with one of the three sealers followed by lateral condensation of gutta-percha. The teeth were placed into 100% humidity at 37 degrees C. After 4 months the roots were notched and fractured longitudinally and the dentin lifted to expose the gutta-percha sealer and dentin walls. Qualitative assessment was in the apical and coronal as to the amount and the pattern of sealer coverage. Coverage was categorized by the amount and location as follows: (a) no sealer; (b) slight-partial; (c) moderate-partial; or (d) complete coverage. Sealer was frequently absent between gutta-percha cones and the canal wall and at times absent between cones, with a general moderate-partial coverage. No sealer group demonstrated complete coverage; however, AH 26 showed more consistent moderate-partial distribution. Coverage was better in the coronal. In conclusion, none of the three sealers showed a continuous layer between the primary gutta-percha obturant and the canal wall or in spaces between cones.

Calcium hydroxide is advocated as an intracanal medication for various purposes, including prevention of posttreatment symptoms. This study assessed whether calcium hydroxide had a pain-controlling effect at different times when compared with no intracanal medication. One hundred forty patients participated. Conditions diagnosed were pulp/periapical pathosis with or without symptoms. At least partial cleaning and shaping was completed. At random, either Ca(OH)2 plus H2O paste or a dry cotton pellet was placed in the canals of half the teeth, respectively. All teeth were temporized with Intermediate Restorative Material. Patients assessed posttreatment pain up to 48 h as none, mild, moderate, or severe. The pain levels in each test group [Ca(OH)2 versus cotton pellet] at each time period were compared statistically with a multiple-regression analysis. There was no significant difference in posttreatment pain between the two groups at any time period or with any diagnosis or symptom. The use of calcium hydroxide as an intracanal medication was unrelated to the incidence and/or severity of posttreatment pain.

There is little evidence for which cold delivery method is most accurate in determining pulp responsiveness. This study compared carbon dioxide dry ice sticks (CO2) versus refrigerant spray (RS) to generate a patient response from different types of teeth restored to varying degrees. Fifteen human patients were selected. In each quadrant, three teeth were identified and the restoration type recorded. Blindfolded patients were randomly tested with either CO2 or RS in a crossover design at two different sessions. Responsiveness was recorded as yes/no and the interval (in seconds) from application to response was determined. Results showed that (a) CO2 and RS were equivalent in producing a pulpal response regardless of tooth and presence of restoration, and (b) CO2 took significantly (p < 0.05) longer to evoke a response than RS using paired t tests. In conclusion, RS and CO2 were equivalent in determining pulpal responsiveness, but the elicited response from RS was faster.

The object of this study was to determine if canal length is altered as a result of straight-line access (SLA) and coronal flaring (CF). Selected were 86 canals of extracted molars and premolars from two groups: straight or severely curved (Schneider curvature <5 degrees and >20 degrees). The reference cusp tip and root-end were flattened to produce reproducible measurements. A #10 file was placed such that the tip extended slightly beyond the apex, with the handle on the referenced cusp. The amount of file protrusion was measured with a stereomicroscope. Then, SLA and CF were performed and the corresponding file replaced to the same coronal reference position. Apical file protrusion was measured again. The change in canal length was determined by the difference in the pre- and post-SLA/CF measurements. A Wilcoxon signed rank test statistically verified that there was a measurable, significant (p < 0.001) change in canal length after SLA and CF. The mean change overall was slight, with a decrease of 0.17 mm. Severe curvature had a slightly greater, significant effect on the amount of change. Tooth type had no significant effect. Changes in working length from SLA and CF, although statistically significant, were very small and clinically unimportant.

A major cause of tooth discoloration is sealer remnants in the pulp chamber after root canal treatment. The purpose of this study was to assess coronal distribution and color changes of four commonly used sealers placed in the pulp chamber after 2 yr. Fifty extracted premolars were cross-sectioned in the coronal third of the root. The chamber contents were removed, and instrumentation was via the canal; then freshly mixed sealer was placed in each chamber. Sealers evaluated were: AH 26, Kerr Pulp Canal Sealer, Roth 801, and Sealapex. The apical access was sealed with white sticky wax, and the tooth was maintained in a moist environment at 37 degrees C for 2 yr. Teeth were split longitudinally, and digital images of the exposed dentin were made, scrambled, and evaluated blindly by trained evaluators for color changes and for presence of sealer in dentin. There was no measurable penetration of sealer into dentin for all groups and no dentin discoloration occurred. The sealers displayed marked discoloration. At 2 yr, the sealers discolored and remained confined primarily to the pulp chamber.

Aim: The present study tested the hypothesis that having two proximal contacts (PCs) at access is associated with improved survival of root canal treated (RCT) teeth, controlling for important presenting conditions, endodontic variables and restorative factors., Methodology: A treatment database at the University of Iowa College of Dentistry was used to identify permanent teeth undergoing obturation between 1 July 1985 and 31 December 1987. The list was restricted to teeth of patients with at least one dental visit in each two-year interval from 1985 to 1996, and a simple random sample of 280 patients (n = 400 teeth) was selected. Dental charts, radiographs, and computerized databases were examined to ascertain variables of interest and to verify study inclusion criteria. Kaplan-Meier survival estimates were generated for the 221 teeth satisfying study inclusion criteria. Multivariate Cox models were developed, with standard errors adjusted to account for clustering of teeth within patients., Results: The final Cox model showed that teeth with < or =1 PC at access were lost at a rate three times that of teeth with 2 PCs (hazard ratio = 3.1; 95% confidence interval = 1.9-5.1), controlling for tooth type, presence of radiographic caries at access, and presence of a crown before or after obturation., Conclusions: Because RCT teeth with two PCs at access experienced substantially better survival than teeth with fewer than two PCs, the influence of PCs on prognosis should be recognized during treatment planning. Future research should employ prospective study designs, capture additional variables, and provide data to support endodontic treatment decisions.

A major cause of tooth discoloration may be sealer remnants in the chamber. The objective of this study was to evaluate, longitudinally, coronal discoloration from four sealers. Extracted premolars were sectioned in the coronal third of the root. The chamber contents were removed and instrumentation was via the canal. The following sealers were bulk introduced into the chamber: AH26, Kerr Pulp Canal Sealer, Roths 801 (nonstaining), and Sealapex. The apical access was sealed with white sticky wax. Teeth were maintained in a moist environment at 37 degrees C. Initial (immediate pretreatment) digital images of the teeth were made for base line comparison. Subsequent images were at 1-, 3-, 9-, and 12-month intervals. Then images were mixed and descriptively evaluated blindly by trained evaluators. Discoloration was induced by the four sealers, with slight to moderate visible changes that increased through 12 months. There was slightly more discoloration with AH26 and Kerr Pulp Canal Sealer. In conclusion discoloration induced by the endodontic sealers produced slight to moderate and generally progressive discoloration over 12 months.

The apical termination of root canal treatment is considered an important factor in treatment success. The exact impact of termination is somewhat uncertain; most publications on outcomes are based on retrospective findings. After vital pulpectomy, the best success rate has been reported when the procedures terminated 2 to 3 mm short of the radiographic apex. With pulpal necrosis, bacteria and their byproducts, as well as infected dentinal debris may remain in the most apical portion of the canal; these irritants may jeopardize apical healing. In these cases, better success was achieved when the procedures terminated at or within 2 mm of the radiographic apex (0 to 2 mm). When the therapeutic procedures were shorter than 2 mm from or past the radiographic apex, the success rate for infected canals was approximately 20% lower than that when the procedures terminated at 0 to 2 mm. Clinical determination of apical canal anatomy is difficult. An apical constriction is often absent. Based on biologic and clinical principles, instrumentation and obturation should not extend beyond the apical foramen.

A maxillary permanent central incisor with a history of trauma, apexification, and internal thermocatalytic bleaching sustained a horizontal fracture at the cementoenamel junction, which necessitated extraction of the tooth. After removal, the root apex was examined histologically and by scanning electron microscopy. An apexification "cap" with unusual anatomic character and structure was observed.

Endodontic needs of today's and tomorrow's growing older adult population present increasing challenges for dental care providers. Biologic and anatomic differences in the dental tissues between older and younger patients must be understood and considered in treatment planning and performance for appropriate endodontic procedures. These differences generally do not contraindicate treatment, which, when performed correctly, will be successful in the elderly patient.

Various instrumentation techniques have been proposed and examined with conflicting results. They include hand and ultrasonic techniques and combinations of the two. In the present study we assessed the effectiveness of four preparation methods for cleaning small, curved root canals, using backscattered-imaging scanning electron microscopy (SEM). The methods were: (i) step-back without initial coronal flaring; (ii) step-back with coronal flaring; (iii) step-back with initial coronal flaring and finished by ultrasonic irrigation; and (iv) ultrasonics only. Eighty freshly extracted maxillary and mandibular molars were randomly placed into four treatment groups of 20 teeth each. After preparation, roots were sectioned longitudinally and examined wet by SEM. Each canal was qualitatively evaluated and the groups compared for removal of debris and smear layer, both overall and at each level (apical, middle and coronal). There were no statistically significant differences between the techniques, either overall or within any of the regions. When comparing regions (regardless of technique) the middle level was cleaner than the apical or coronal levels. In conclusion, efficacy differed little among the techniques; none of them completely removed smear layer and all left debris.

Objectives: The purpose of this study was to assess bacterial leakage of a mixed anaerobic community of organisms in obturated canals after post space preparation., Study Design: A mixed microbial community of strict anaerobic organisms (F. nucleatum, P. micros and C. rectus) was developed. With the use of an in vitro model system, coronal leakage was assessed in 40 anterior teeth after obturation and post space preparation. The specific leakage time in days for each organism to penetrate through the obturating material was determined. In addition, colonization of the apical canal space was assessed by scanning electron microscope after longitudinal splitting of randomly selected specimens., Results: Eighty percent of the teeth demonstrated coronal leakage of F. nucleatum and C. rectus by the 90 day interval. Bacterial penetration occurred from 48 days to 84 days. Scanning electron microscope examination showed a heterogeneous biofilm of coccal and bacillary species colonizing the apical portion of the canal wall., Conclusions: This study demonstrated that coronal leakage phenomena do occur after loss of coronal seals. The model system developed using mixed, anaerobic bacterial cultures is more clinically relevant and may be used to assess bacterial penetration through gutta percha obturation.

Objective: To determine the prevalence of neonatal circumcision immediately following delisting of the procedure in Ontario and to examine parents' knowledge, attitudes, and behaviours regarding circumcision., Design: Cross-sectional survey., Setting: Perinatal tertiary care centre in southwestern Ontario., Participants: Of the 151 mothers approached, three were excluded because they did not speak English and two declined participation; 112 of 146 mothers of healthy male newborns responded for a response rate of 77%., Main Outcome Measures: Circumcision status of infant and parents' knowledge, attitudes, and behaviour., Results: The circumcision rate before delisting had been 56.2%; in the months immediately after, the rate was 59.8% (95% confidence interval was 51%, 69%). Mothers of infants in the outcome groups did not differ significantly in any demographic feature other than education, where the group deciding against circumcision reported higher education levels (Wilcoxon nonparametic two-sample test: zeta = 2.29, P = 0.02). Mothers who chose circumcision listed medical (59%) and sociocultural considerations (40%) a most important to their decision. Father's circumcision status was strongly associated with the infant's (chi 2[df 1] = 25.13, P = 0.0001). Although 74% discussed circumcision with their family physicians, many parents were not well informed about risks or benefits. Anesthetic use during circumcision was reported by 29%, but 48% did not know whether any had been used., Conclusions: The prevalence of neonatal circumcision did not change after delisting. Informed consent was often lacking. Sociocultural issues are important to some parents and need to be addressed in the consultation process.

Nickel-titanium instruments purportedly resist deformation and loss of sharpness better than do stainless steel instruments but may be more susceptible to breakage. The processes of wear and breakage of nickel-titanium and stainless steel instruments were examined. Sixty files of five types (12 each) and three manufacturers were used. All were used repeatedly in curved canals until failure or for a maximum of 22 minutes. Each instrument was examined with scanning electron microscopy both new (control) and at spaced intervals for evidence of wear and fatigue. All new instruments were of good quality. Stainless steel instrument tended to wear the most rapidly, and next were nickel-titanium rotary instruments; the most resistant to wear were nickel-titanium hand instruments. There were few instrument separations. In general, nickel-titanium (particularly hand) instruments resisted deterioration better than did stainless steel. Nickel-titanium rotary instruments (2 of 12) had the most breakage.

Unlabelled: The success of root canal treatment can be subjectively evaluated both clinically and radiographically. Normally, the recall radiograph is the main factor in evaluating success or failure., Objectives: This study evaluated periapical areas of root canal treated teeth by correlating radiographic and histologic findings., Study Design: Jaws were resected from cadavers and radiographed. Those teeth that had received root canal treatment were evaluated for success or failure based on radiographic criteria. Teeth and surrounding bone were then removed en bloc and prepared for light microscopy. Untreated teeth without periapical pathosis were examined as controls., Results: Root canal treated teeth classified as failures were found to consistently have inflammatory resorptive lesions at the periapices. In contrast, those treated teeth classified as radiographically successful showed varying reactions ranging from normal uninflamed to mildly inflamed., Conclusions: Those classified as failure showed consistent inflammation. However, the majority of our examined treated teeth were radiographically normal and exhibited no periapical inflammation.

Cellular hypoxia may be a useful indication of tissue distress in the dental pulp that could be used to investigate the early stages of pulpal responses. Tritiated misonidazole (3H-MISO) is a marker which preferentially labels cells with decreased oxygen tension (hypoxia). The experiments reported here were carried out to determine whether this agent could distinguish between hypoxic and normoxic pulp and periapical tissues. Rats were injected intra-peritoneally with either 3H-MISO, unlabeled MISO, or saline, then divided into normoxic, hypoxic, and control groups. Normoxic animals were maintained at ambient pressure. We induced hypoxia by maintaining animals in a hypobaric chamber at 0.5 atm for 24 hrs. 3H-MISO retention was assessed by quantitative analysis of tissue autoradiographs. 3H-MISO retention rates in normoxic animals showed little variation except for increased retention in mature ameloblasts and immature odontoblasts in the continually erupting incisor. In both incisor and molar pulps, hypobaric hypoxia significantly increased 3H-MISO retention when compared with normoxic controls. Hypobaric hypoxia also resulted in intense 3H-MISO retention in cellular cementum, periodontal ligament, osteocytes, and, occasionally, in molar pulp horn odontoblasts. This study demonstrated that, with standard autoradiographic techniques, 3H-MISO can label induced hypoxic disturbances in the pulp and surrounding periodontium.

The action of chemicals such as calcium hydroxide (Ca(OH)2) and sodium hypochlorite (NaOCl) that are used as tissue solvents may be enhanced by prolonged contact. The objective of this study was to determine if sealing Ca(OH)2 and NaOCl into the canal space would improve debridement of both the main canal and areas inaccessible to files. Mesial root canals of 75 freshly extracted mandibular molars were step-back hand-instrumented. Another six molars were controls. Either Ca(OH)2, NaOCl, or no medication was sealed in the canals for 1 or 7 days. Canals were finally irrigated with H2O and prepared for histological evaluation. The cleanliness of main canals and inaccessible areas (isthmi and fins) at the apical, middle, and coronal thirds was examined, scored, and compared by nonparametric statistical analysis. Results showed no significant differences among different groups in either the 1-day or 7-day time intervals in either the main canal or inaccessible areas. Instrumentation combined with NaOCl irrigation alone accounted for the removal of tissue in the main canal. In conclusion, in this system, prolonged contact with Ca(OH)2 and NaOCl was similarly ineffective; neither contributed significantly to canal debridement.