0704 Association of high-risk obstructive sleep apnea with inflammatory markers in asymptomatic young and middle-aged adults in Miami Heart (MiHeart) Study at Baptist Health South Florida

Introduction

Obstructive Sleep Apnea (OSA) is associated with elevated inflammatory markers in those with cardiovascular disease (CVD). In contrast, there are limited data to support this association in asymptomatic individuals. The Miami Heart Study measured high sensitivity C-reactive protein (hs-CRP), Interleukin 6 (IL-6) and TNF- Alpha in a cohort of asymptomatic individuals from the general population. We hypothesized that there will be significant association of high OSA risk with inflammatory markers in Miami Heart Study cohort free of CVD.

Methods

We analyzed data for 2359 clinical CVD-free participants from the Miami Heart Study, age 40-65 years (May 2015-Sept 2018). High OSA risk included those with an OSA diagnosis and/or those with high risk using the Berlin questionnaire. Poisson regression analyses were utilized to examine the associations between high OSA risk (reference: low risk) and hs-CRP, IL-6 and TNF alpha levels (continuous), in univariate and multivariate models (adjusting for age, sex, race/ethnicity [model 2], and BMI, diabetes, hypertension, high cholesterol and smoking [model 3]).

Results

800 (34%) participants were categorized as high OSA risk. Those with high OSA risk tended to be Hispanic, male, and with a higher CVD risk factor burden, especially obesity (64% vs 17%, p < 0.005) when compared to those with low OSA risk. Patients with high OSA risk had higher median values of hs-CRP (2.1 vs 1.0), IL-6 (2.0 vs 1.4), and TNF-alpha (1.2 vs 1.1) when compared to those with low OSA risk (all p < 0.001). When adjusting for age, sex, and race/ethnicity, the mean difference between patients with high and low OSA risk in hs-CRP was 1.86 (95% CI 1.69, 2.02), and 0.85 (95% CI 0.71, 0.99) in IL6. When further adjusting for CVD risk factors, these differences were attenuated, but statistically significant (hs-CRP [0.32, 95% CI 0.16, 0.48]; IL6 [0.37, 95% CI 0.21, 0.53]). In adjusted analyses, TNF-alpha was not statistically different between OSA risk populations.

Conclusion

Individuals at high risk for OSA had significant higher levels of hs-CRP and IL6, signaling to potential role of OSA in mediating the increased inflammatory markers in asymptomatic CVD risk free individuals.

Support (If Any)

Baptist Health South Florida

0705 Association of high risk obstructive sleep apnea with atherosclerotic plaque, coronary stenosis and coronary artery calcium score in asymptomatic young and middle-aged adults in The Miami Heart (MiHeart) Study at Baptist Health South Florida

Introduction

Obstructive Sleep Apnea (OSA) is associated with clinical cardiovascular disease (CVD). There are limited data evaluating association with subclinical CVD measured by cardiac computed tomography (CT). We hypothesized there would be significant association between high OSA risk and atherosclerotic plaque, coronary stenosis, and coronary artery calcium (CAC) score in Miami Heart Study cohort free of CVD.

Methods

Data from CVD free 2359 participants, age 40-65 years (May 2015-Sept 2018) from greater Miami were analyzed. Cardiac CT measured CAC, coronary plaque burden and stenosis. High OSA risk was defined as either OSA diagnosis and/or a high risk from Berlin questionnaire. Logistic regression examined association between high OSA risk (reference low OSA risk) and any plaque, coronary stenosis >50%, and CAC (> 0 and > 100 vs 0) in unadjusted models, and after accounting for age, sex, race/ethnicity (model 2), and BMI, diabetes, high cholesterol, and smoking (model 3).

Results

800 (34%) participants had high OSA risk; were more likely to be male, Hispanic, with higher CVD risk factor burden compared to low OSA risk. High OSA risk had higher prevalence of any plaque (60% vs 44%), coronary stenosis ≥ 50% (8.3% vs 4.8%), CAC scores >0-99 (34% vs 26%), and CAC score ≥ 100 (16% vs 12%), compared to low OSA risk (all p < 0.05). High OSA risk was associated with higher odds of any plaque, coronary stenosis ≥ 50%, high-risk plaque features, CAC > 0 and CAC ≥ 100 in univariable models. When adjusting for age, sex and race/ethnicity, these patterns persisted, with 1.58 higher odds of any plaque (95% CI 1.31, 1.91), 1.54 higher odds of coronary stenosis ≥ 50% (95% CI 1.08, 2.20), 1.37 higher odds of having CAC > 0 (95% CI 1.13, 1.66). Associations became non-statistically significant when adjusting for CVD risk factors, except any plaque, which was independently associated after fully adjusted (OR 1.31 (1.05, 1.63).

Conclusion

Individuals with high risk for OSA, significantly prone for CVD risk factor, have higher likelihood for presence of any plaque, significant stenosis and CAC scores > 0, with these associations mostly mediated by CVD risk factors.

Support (If Any)

Baptist Health South Florida

795 Real World Challenges and Barriers for Positive Airway Pressure Therapy Use in Acute Ischemic Stroke Patients

Introduction

Untreated obstructive sleep apnea (OSA) in patients with acute ischemic stroke (AIS) increases morbidity and mortality post-stroke. However, diagnosing and treating OSA in AIS is challenging. As such, we aimed to determine the feasibility of portable monitoring (PM) for diagnosis and positive airway pressure (PAP) therapy for treatment of OSA in an inpatient stroke population.

Methods

We recruited inpatients with AIS from the Cleveland Clinic. Those who consented underwent PM; participants with a respiratory event (REI) ≥10 were offered auto-titrating positive airway pressure therapy (APAP). Ease-of-use questionnaires were completed. We summarized categorical variables using n(%) and continuous variables using mean±SD or median [IQR].

Results

27 participants (age 59.8±11.8, 51.9% female, 51.9% African American, BMI 33.3±11.4) enrolled. The study ended early due to Medicare contracting that forced most patients to complete stroke rehabilitation outside the Cleveland Clinic health system. 69.6% had large vessel occlusions and 52% had moderate/severity disability (Modified Rankin score ≥2). PM was attempted in 23 participants and successful in 19. Nursing and patients rated the PM device as highly easy to use. 11 of 14 patients who had an REI ≥10 consented to APAP titration, but only 5 continued APAP after discharge. Four patients who initially said APAP was easy to use noted that their stroke interfered with their APAP use at home.

Conclusion

This study demonstrates the challenges in the assessment and treatment of OSA in an acute ischemic stroke population, highlighting the necessity for further research into timely and feasible screening and treatment.

Support (if any)

ResMed

Impact of the sleep apnea management group clinic on positive airway pressure adherence

Background

Positive airway pressure (PAP) adherence is critical for managing obstructive sleep apnea (OSA). We postulate that group-based Sleep Apnea Management (SAM) clinic, which harnesses the benefits of providing mutual support as well as facilitates access to system-based resources and education, will confer improvements in PAP adherence.

Methods

Data from SAM clinic attendees from January 2017 to June 2018 were retrospectively analyzed. Adherence data at SAM baseline visit and 1-3 months follow-up were collected. Average PAP usage from all-days and days used were analyzed along with demographics, co-morbidities, and Epworth Sleepiness Scale. Adherence was defined as >4 hours a night for ≥70% of nights over a 30-day period. Key structural elements of the SAM group clinic model were co-presence of the OSA care team members and peer group support. Key efficiency elements were group education and the prompt-to-patient multidisciplinary troubleshooting adherence barriers.

Results

Of 110 SAM clinic attendees, average age was 60.9±12.7 years, 53% were men, and 46% Caucasian. At baseline, the mean for average-all-days usage was 4.2 hours, mean average-days-used usage was 5.2 hours, and mean percentage-of-days usage ≥4 hours was 57%. At follow-up, the mean average-all-days usage increased 1.2 hours (p<0.001), mean average-days-used usage increased 0.8 hours (p<0.001), and the mean percentage-of-days with usage ≥4 hours increased 16% (p<0.001). At baseline, 46% of patients met criteria for adherence, which increased to 66% at follow-up.

Conclusion

In this study, after the SAM clinic, all PAP adherence parameters improved significantly. This observational study serves as a proof of concept study for future trials pertaining to group clinic in managing PAP adherence in OSA.

0650 Impact of Upper Airway Stimulation Therapy on 24 Hour Ambulatory Blood Pressure Monitoring

Introduction

Upper airway stimulation (UAS) is recommended treatment for moderate to severe obstructive sleep apnea (OSA) in select patients. Existing data have not focused on gold standard 24 hour ambulatory blood pressure monitor (ABPM) to elucidate the impact of UAS. We hypothesize that UAS reduces ABPM indices characterized using objective sleep-wake from actigraphy data over 12-month follow-up period.

Methods

A prospective sub-study of the Inspire ® post-approval study at the Cleveland Clinic was designed to examine the effect of UAS on 24-hour ABPM measures post-implantation by examining blood pressure (BP) at baseline, and-2, 6, and 12 months follow-up. Actigraphy data was contemporaneously collected. Paired T-tests were used to evaluate BP changes over time. Repeated measure correlations measured within-patient associations between BP and actigraphy measures.

Results

Average age and BMI were 62.4 +/-12.9) years and 30.1 +/-3.3 kg/m2, 73.3% males and all Caucasian. The mean baseline systolic, diastolic and mean arterial pressure (MAP) were 119.7+/-12.9 mmHg, 74.3+/-7.4 mmHg and 89.3+/- 8.1 mmHg. There were no changes to number, type or dosage of BP medications.

At 12 months, there were non-significant overall mean reduction in systolic [-0.55mmHg, p=0.75], diastolic [-0.73mmHg, p=0.63], and MAP [-0.55mmHg, p=0.71]. Mean sleeping systolic, diastolic and MAP changed by -4.36(p=0.34), -1.45 (p=0.57), -2.18 (p=0.50), respectively. Positive correlations above 0.25 (p&lt;0.10) were observed between all dipping percentage measures and total sleep time. Negative correlations were seen between overall systolic, diastolic and MAP with sleep latency (-0.22, p=0.19, -0.35, p=0.031 and -0.29, p=0.075 respectively). No significant changes in BMI was observed, but average hours of usage decreased over time.

Conclusion

Although consistent reduction of BP measures were observed post-UAS implantation, findings were not statistically significant. It is unclear whether this is due to insufficient sample size or true lack of effect. Larger-scale clinical and mechanistic studies are needed to enhance understanding of UAS-related vascular influences.

Support

Funded: Inspire Medical Systems

0614 Diurnal Patterning of Autonomic Measures in Sleep Apnea and Paroxysmal Atrial Fibrillation and Response to Continuous Positive Airway Pressure Therapy

Introduction

Diurnal patterning of autonomic function in paroxysmal atrial fibrillation (PAF) and sleep disordered breathing (SDB) is unknown. We hypothesize heart rate variability (HRV) as surrogates of autonomic function, exhibit diurnal differences in PAF relative to SDB severity and treatment.

Methods

We leveraged the Sleep Apnea and Atrial Fibrillation Biomarkers and Electrophysiologic Atrial Triggers (SAFEBEAT,NCT02576587) study focused on participants with PAF and SDB (apnea hypopnea index,AHI≥15,3% oxygen desaturation hypopnea). Attended 16-channel polysomnography (PSG) and continuous ECG monitoring (Heartrak Telemetry®) for 7-21 days was performed at baseline and after 3-months of continuous positive airway pressure (CPAP). Linear mixed-effects models (least square means,95%CI) were used to assess relationships between daily average HRV measures (frequency domain:LF,HF,LF/HF;time domain:MNN,RMSSD,SD1,SD ratio and novel non-linear:DFA-alpha measures) with SDB (AHI),%sleep time with SaO2&lt;90%(TRT&lt;90): per 5-unit increase),effect of 3-month CPAP relative to sleep-wake and statistical interaction of sleep-wake. Analyses were conducted using SAS version v.9.4, Cary, NC.

Results

The analytic sample was comprised of 33 cases with PAF and SDB:61.1±11.7 years,62.5% male, BMI:33.9±7.2kg/m2,75% Caucasian,AHI 15.1 (IQR: 4.4,29.4) and 68.8% on atrioventricular nodal blocking medications. AHI was associated with frequency (HF:0.08[0.01,0.16] and LF/HF:-0.11[-0.20, -0.01]), time (SD1:0.08[0.02,0.14] and SD ratio: 0.09[0.04,0.14]) and non-linear (DFA-alpha1: -0.02[-0.036,-0.003]) domain measures during wake, but not sleep. Significant sleep-wake and AHI as well as TRT&lt;90 interactions relative to HRV measures were observed (p≤0.001). Only SD ratio was associated with TRT&lt;90 (0.12[0.03,0.24]). Baseline to follow-up CPAP time domain measures were altered mainly during wake versus sleep with MNN increased 0.13: [0.08,0.19],p&lt;0.001; RMSSD increased 0.13 [0.08,0.19], p&lt;0.001; SD1 increased 30% [0.09,0.55], p=0.004; SD ratio increased 20% [0.01,0.43], p=0.033,and also frequency domain: HF increased 33%[0.03,0.72], p=0.028.

Conclusion

SDB defined by AHI--more so than nocturnal hypoxia--was associated with surrogate autonomic measures impacted by CPAP intervention during wake and not sleep in PAF. SDB-related autonomic influences in PAF appear to be more pronounced during wakefulness suggesting long-term potentiation-like influences.

Support

This study was supported by the National Heart, Lung and Blood Institute (NHLBI) [Grant R01 HL108493] and National Institutes of Health (NIH) National Center for Research Resources [Grant UL1 RR024989]

0637 Comparison of AHI and ESS Outcomes Between Patients with Obstructive Sleep Apnea Undergoing Sleep Surgery versus Upper Airway Stimulation

Introduction

Single or multi-level soft tissue surgical interventions are common options for CPAP-intolerant patients with OSA. Upper Airway Stimulation (UAS) is an alternative option using an implantable hypoglossal nerve stimulator. We compared patient outcomes between traditional sleep surgery (TSS) and UAS.

Methods

We selected patients who underwent TSS (including palate, oropharynx, tongue, and/or epiglottis-based procedures) for OSA and also met general UAS criteria (BMI≤35, AHI between 15-65, absence of palate concentric collapse during DISE, if available) for chart review. UAS outcomes were collected from the ADHERE international registry. For both groups, post-op AHI was collected, including full-night UAS efficacy studies. Data are presented as mean and standard deviation.

Results

The TSS group (n=284) and UAS group (n=541) were predominantly male and overweight. The TSS group was younger than UAS (47±12 vs 60±11 years, p&lt;0.001). At baseline, both groups had severe OSA with AHI of 34±14 and 36±15 (p=0.23) and excessive daytime sleepiness with ESS of 12±5 and 12±6, (p=0.38), respectively. TSS follow-up was 169±151 days vs 392±181 days for UAS, which was significantly different. UAS had significantly larger decrease in AHI than TSS (-21/h±18 vs -16/h±16, p&lt;0.0001). Both groups had a large decrease in ESS, however, the UAS group had a slightly smaller decrease, (-6±5 vs -5±5, p=0.01). Using the Sher response criteria of 50% AHI reduction and ≤ 20 events/hour, UAS had a 70% response rate vs 51% for TSS.

Conclusion

This study represents largest and first international, multicenter comparison of UAS to traditional surgical interventions for OSA, albeit with limitations of potential differential patient selection. While both TSS and UAS show similar improvement in symptoms, upper airway stimulation has a larger reduction of AHI with higher rates of therapy response than traditional sleep surgery

Support

ADHERE data assistance from Inspire Medical (Minneapolis, MN)

CPAP Adherence Predictors in a Randomized Trial of Moderate-to-Severe OSA Enriched With Women and Minorities

BACKGROUND

Suboptimal CPAP adherence in OSA clinical trials involving predominantly white men limits interpretability and generalizability. We examined predictors of CPAP adherence in a clinical trial enriched with minorities.

METHODS

The Sleep Apnea Stress Study-a randomized, double-blind, sham-controlled trial of patients with moderate-to-severe OSA-included participants with complete 8-week adherence data (n = 138). Overnight 14-channel polysomnography, anthropometry, socioeconomic status, mood questionnaires, and week 1 CPAP adherence were analyzed via adjusted linear models relative to CPAP adherence (average minutes per night usage).

RESULTS

Overall, age was 51 ± 12 years, 55% of the patients were male, 55% were white, BMI was 36.7 ± 7.7 kg/m², and median apnea-hypopnea index was 20 (interquartile range, 13-37). In univariate analyses adherence increased with randomization to active CPAP (81 min; 95% CI, 30-132), increasing age (35 min/decade; 95% CI, 13-57), white race (78 min, 95% CI, 26-129), and per hour of week 1 adherence (41 min, 95% CI, 32-51). Active CPAP (48 min, 95% CI, 6-91), increasing age (27 min/decade, 95% CI, 10-44), and higher 1-week adherence (36 min/h, 95% CI, 27-46) were significantly associated with improved adherence in multivariable analyses. Subgroup analyses showed stronger associations of adherence with treatment arm in whites and increasing age in minorities. Increasing age and white race were more strongly associated with adherence in women.

CONCLUSIONS

In this trial with near-even sex distribution and high ethnic minority representation, we identified CPAP assignment, increasing age, and early adherence to be associated with improved adherence in addition to sex-specific and race-specific adherence differences. These results can inform targeted clinical trial adherence optimization strategies.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT00607893; URL: www.clinicaltrials.gov.

Association between obstructive sleep apnea severity and endothelial dysfunction in an increased background of cardiovascular burden

The objective of this study is to examine whether increasing obstructive sleep apnea (OSA) severity is associated with worsening endothelial function. The design is a cross-sectional examination of the baseline assessment of a multi-centre randomized controlled clinical trial examining the effects of oxygen, continuous positive airway pressure (CPAP) therapy or lifestyle modifications on cardiovascular biomarkers. Participants were recruited from cardiology clinics at four sites. Participants with an apnea-hypopnea index (AHI) of 15-50 and known cardio/cerebrovascular disease (CVD) or CVD risk factors were included. OSA severity indices [oxygen desaturation index (ODI), AHI and percentage of sleep time below 90% oxygen saturation (total sleep time <90)] and a measure of endothelium-mediated vasodilatation [Framingham reactive hyperaemia index (F-RHI) derived from peripheral arterial tonometry (PAT)] were assessed. The sample included 267 individuals with a mean AHI of 25.0 ± 8.5 SD and mean F-RHI 0.44 ± 0.38. In adjusted models, the slope of the relationship between ODI and F-RHI differed above and below an ODI of 24.6 (P = 0.04), such that above an ODI of 24.6 there was a marginally significant decline in the geometric mean of the PAT ratio by 3% [95% confidence interval (CI): 0%, 5%; P = 0.05], while below this point, there was a marginally significant incline in the geometric mean of the PAT ratio by 13% (95% CI: 0%, 27%; P = 0.05) per 5-unit increase in ODI. A similar pattern was observed between AHI and F-RHI. No relation was noted with total sleep time <90 and F-RHI. There was evidence of a graded decline in endothelial function in association with higher levels of intermittent hypoxaemia.

Are sleep symptoms predictors of resistant hypertension in a population-based sample? Findings from the National Health and Nutritional Examination Survey

The aim of this study was to test the association of self-reported sleep symptoms to those identified with severe hypertension in a nationally representative sample of adults. Self-reported and study-measured health and sleep characteristics were collected by the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2008. Of 10,526 individuals with completed sleep surveys participating in the study, the authors identified 379 patients with severe hypertension defined as those treated with ≥ 3 antihypertensive medications including a diuretic; 110 of these had resistant hypertension (RHTN) despite therapy, while 269 were controlled for severe hypertension (CSHTN). Patients with RHTN were more likely to be married, less educated, smoke, and self-report unsatisfactory health and diabetes when compared with patients with CSHTN. Multivariate analyses showed that poorly controlled diabetes (glycated hemoglobin >7%) was the strongest predictor of RHTN (odds ratio, 3.0; 95% confidence interval, 1.2-7.9). Unsatisfactory health (odds ratio, 1.7; 95% confidence interval, 1.7-2.7) was also associated with RHTN. Poorly controlled diabetes and self-reported unsatisfactory heath showed significant association with RHTN. Contrary to expectations, there was no significant association between self-reported snoring/snorting and RHTN, when other factors were examined. The association between poorly controlled diabetes and RHTN warrants further emphasis on strict control of diabetes in these individuals.

Effect of continuous positive airway pressure on an atrial arrhythmia in a patient with mild obstructive sleep apnea

Cardiac arrhythmias have been reported in up to half of individuals with obstructive sleep apnea (OSA) and have been proposed to be one of the factors contributing to their increased mortality. Several studies have demonstrated evidence of an association between OSA and a number of cardiac arrhythmias. The mechanisms of arrhythmogenesis in OSA may be due to enhanced vagal output triggered by a combination of apnea and hypoxemia. This case demonstrates a dose-dependent reduction in atrial ectopy with increasing continuous positive airway pressure (CPAP) in the setting of mild sleep apnea.

Construction and evaluation of cDNA libraries for large-scale expressed sequence tag sequencing in wheat (Triticum aestivum L.)

A total of 37 original cDNA libraries and 9 derivative libraries enriched for rare sequences were produced from Chinese Spring wheat (Triticum aestivum L.), five other hexaploid wheat genotypes (Cheyenne, Brevor, TAM W101, BH1146, Butte 86), tetraploid durum wheat (T. turgidum L.), diploid wheat (T. monococcum L.), and two other diploid members of the grass tribe Triticeae (Aegilops speltoides Tausch and Secale cereale L.). The emphasis in the choice of plant materials for library construction was reproductive development subjected to environmental factors that ultimately affect grain quality and yield, but roots and other tissues were also included. Partial cDNA expressed sequence tags (ESTs) were examined by various measures to assess the quality of these libraries. All ESTs were processed to remove cloning system sequences and contaminants and then assembled using CAP3. Following these processing steps, this assembly yielded 101,107 sequences derived from 89,043 clones, which defined 16,740 contigs and 33,213 singletons, a total of 49,953 "unigenes." Analysis of the distribution of these unigenes among the libraries led to the conclusion that the enrichment methods were effective in reducing the most abundant unigenes and to the observation that the most diverse libraries were from tissues exposed to environmental stresses including heat, drought, salinity, or low temperature.

Histone acetylation is required to maintain the unfolded nucleosome structure associated with transcribing DNA

Nucleosomes associated with transcribing chromatin of mammalian cells have an unfolded structure in which the normally buried cysteinyl-thiol group of histone H3 is exposed. In this study we analyzed transcriptionally active/competent DNA-enriched chromatin fractions from chicken mature and immature erythrocytes for the presence of thiol-reactive nucleosomes using organomercury-agarose column chromatography and hydroxylapatite dissociation chromatography of chromatin fractions labeled with [3H]iodoacetate. In mature and immature erythrocytes, the active DNA-enriched chromatin fractions are associated with histones that are rapidly highly acetylated and rapidly deacetylated. When histone deacetylation was prevented by incubating cells with histone deacetylase inhibitors, sodium butyrate or trichostatin A, thiol-reactive H3 of unfolded nucleosomes was detected in the soluble chromatin and nuclear skeleton-associated chromatin of immature, but not mature, erythrocytes. We did not find thiol-reactive nucleosomes in active DNA-enriched chromatin fractions of untreated immature erythrocytes that had low levels of highly acetylated histones H3 and H4 or in chromatin of immature cells incubated with inhibitors of transcription elongation. This study shows that transcription elongation is required to form, and histone acetylation is needed to maintain, the unfolded structure of transcribing nucleosomes.

Evaluation of the antibacterial effects of intracanal Nd:YAG laser irradiation

Fifty canals of extracted single-rooted teeth were prepared to a size 50 master apical file, sterilized in ethylene oxide, and inoculated with a known quantity of Bacillus stearothermophilus spores. Five groups of 10 canals each were used. The control group received no treatment. The four treatment groups were exposed to pulsed Nd:YAG laser radiation or 0.5% NaOCl alone and in combination. The root canals were flushed with sterile distilled water to recover spores, and serial dilutions were incubated on blood agar and the number of colony-forming units recovered was determined. Analysis of the data indicated a 2-log reduction in colony-forming units among the four treatment groups as compared with the controls; however, no significant differences were observed among the treatment groups. In none of the treatment groups were the root canals sterilized.

Osseous reaction to implanted ZOE retrograde filling materials in the tibia of rats

The osseous reaction of IRM and EBA cement were studied utilizing an intraosseous implant technique in rats. Samples of IRM, EBA cement, and amalgam were placed into polyethylene tubes and subsequently introduced surgically into rat tibias. Specimens of each were evaluated histologically after 7, 14, 21, 56, and 100 days. The IRM and amalgam samples demonstrated essentially complete healing at 56 days. The EBA cement samples displayed a slightly greater inflammatory response up to the 56-day interval; however, they also showed complete healing by 100 days. A favorable osseous reaction was seen with both of these zinc oxide-eugenol materials.

Prevalence and morphologic features of apical deltas in the canine teeth of dogs

Prevalence and morphologic features of the apical delta in the canine teeth of dogs were determined to assist clinicians in the endodontic treatment of these teeth. Eighty-two canine teeth from mixed-breed dogs were cleared and dyed to outline root canal ramifications. Apical deltas were classified according to location in the dental arch, number of ramifications, and vertical extent of these ramifications from the apical terminus. A classification system was devised to aid in identification and treatment of the delta. Recommendations were made regarding indications for conventional and/or surgical endodontic therapy depending on the type of delta encountered. Apical deltas were detected in 69.5% of the canine teeth studied. Surgical endodontic intervention should be seriously considered when the delta is found to extend a distance > 1 mm from the apical terminus.

Thermal effects of continuous wave CO2 laser exposure on human teeth: an in vitro study

The thermal effects of continuous wave carbon dioxide laser irradiation on human teeth were investigated. Internal temperature changes were monitored by means of electrical thermistors implanted within the pulp chambers of 20 extracted, unerupted human molar teeth. One-hundred test exposures at various powers and durations were obtained. Linear regression/correlation analysis of the data suggests a direct relationship between the independent variable, exposure energy (joules), and the dependent variable, internal temperature, under the conditions of this study.