Appraising and comparing the role of autogenous periosteal graft as a barrier membrane in the treatment of intrabony defects in chronic periodontitis cases: A systematic review and meta-analysis.

Periodontal regeneration refers to procedures aimed at restitution of lost supporting tissue around the periodontally compromised tooth. Regenerative procedures very often include the use of barrier materials to encourage the growth of key surrounding tissues. The current study aimed to evaluate the effectiveness of autogenous periosteal graft as a barrier membrane for the treatment of intrabony defects in chronic periodontitis patients. A total of four data bases MEDLINE (by PubMed), Cochrane database, EBSCO, and Google Scholar were explored to identify the studies in English up to December 2022. An additional hand search of relevant journals was also done. A team of three independent reviewers screened the retrieved articles using the inclusion criteria. Randomized control trials (RCTs) evaluating the effectiveness of autogenous periosteal grafts in the treatment of intrabony defects in chronic periodontitis cases were included in the study. A total of six relevant articles were recognized for data procurement. A total of 117 patients with 68 sites with an age range between 18 years and 55 years were selected. Outcome variables examined were pocket depth (PD), clinical attachment level (CAL), radiographic bone defect fill (BDF), gingival recession (GR), plaque index (PI), gingival index (GI) and bleeding on probing (BOP). Data were analyzed using Revman 5.3 software. The mean differences and 95% confidence interval were used to illustrate the estimate of effect size. There is an equal effect in both groups for the PI, GI, and BOP reduction. For PD reduction, the result was in the favor of periosteal graft with open flap debridement (OFD) group. For CAL gain, radiographic BDF and GR, results also favored the periosteal graft, but no statistically significant difference was found amongst the groups. Within the limitation of the study, it seems that the autogenous periosteal graft can be used successfully along with OFD to treat intrabony defects in chronic periodontitis patients.

Assessment of microhardness and color stability of micro-hybrid and nano-filled composite resins.

BACKGROUND AND AIMS: Composite resins are among the most popular restorative dental materials because of the strength and esthetic properties. The goal of this study was to assess the effect of commonly consumed beverages on microhardness and color stability of microhybrid (MH) and nanofilled NF) composite resins. MATERIAL AND METHODS: 240 samples were prepared from the composite material [MH = 120 (material I) and NF = 120 (material II)] and allocated into eight groups of 30 samples. In each group, half of the samples were tested for microhardness and another-half for color stability. After baseline measurements, the samples were immersed in test media, that is, distilled water and beverages (tea, cola, and coffee) for 15 days. Microhardness and color stability measurements were carried out after 15 days to assess the effect of beverages. The color stability and microhardness values were compared and evaluated by analysis of variance (ANOVA) using Tukey's alteration test. RESULTS: It was reported that the microhardness decreased for both the materials after immersion in all the beverages. Percentage change in microhardness was considerably higher in material II in comparison to the material I in cola drink. Color change was significantly higher in material II compared to material I in water and coffee. Cola drink caused the maximum change in microhardness among all the beverages and coffee caused the maximum color change among all the beverages. CONCLUSION: Both composite materials (I and II) showed a reduction in microhardness and change in color after immersion in a different type of test media.

Evaluation of sagittal condylar guidance angles using computerized pantographic tracings, protrusive interocclusal records, and 3D-CBCT imaging techniques for oral rehabilitation.

OBJECTIVE: The goal of registering the condylar guidance is to recreate the patient's occlusion as exactly as possible on the articulator, and is therefore essential for successful prosthodontic rehabilitation. Clinical, radiographic, and pantographic methods are used to determine sagittal condylar guidance angles (SCGAs). These methods generate different angles in the same patients. The present study is the first disquisition to evaluate and correlate SCGAs determined by the use of pantographic tracing (PT), protrusive records (PR), and radiographic (CBCT) techniques. MATERIALS AND METHODS: The condylar guidance was measured using PT, PR, and CBCT imaging techniques in 23 nonpatient participants aged between 18 and 30 years irrespective of sex. PT was recorded using Cadiax® Compact system, a computerized recorder of SCGAs. PR was obtained using polyvinyl siloxane bite registration material, transferred to a semiadjustable articulator (Denar Mark II, Whip Mix Corp., USA) using facebow transfer (Denar Mark II, Whip Mix Corp., USA) and CR records, to determine SCGAs. Images of the mid-facial region were obtained using CBCT scan for 3D reconstruction. The angle formed between Frankfort horizontal plane (FHP) and a line extending from the most supero-anterior point on the glenoid fossa to the most convex point on the apex of articular eminence (AE) was measured to obtain SCGAs. RESULTS: The mean left and right SCGAs were as follows: PT (34.42° and 33.93°, respectively), PR (32.14° and 31.82°), and CBCT (38.96° and 38.12°). The Pearson coefficients for the correlations with PT and PR on the left and right sides were 0.899 and 0.907, respectively, while it was 0.911 and 0.934, and 0.842 and 0.874 from PT and CBCT, and PR and CBCT, respectively. CONCLUSION: Strong correlations were found between SCGAs obtained using PT, PR, and CBCT techniques.

Long-lasting effects of feline amygdala kindling on monoamines, seizures and sleep.

This report describes the relationship between monoamines, sleep and seizures before and 1-month after amygdala kindling in young cats (<1 year old; n=8; six female and two male). Concentrations (fmoles of norepinephrine or NE, dopamine or DA and serotonin or 5-HT) were quantified in consecutive, 5-min microdialysis samples (2 microl/min infusion rate) from amygdala and locus ceruleus complex (LC) during four, 6-8-h polygraphic recordings before (n=2) and 1 month post-kindling (n=2); 5-min recording epochs were temporally adjusted to correspond to dialysate samples and differentiated according to dominant sleep or waking state (lasting > or =80% of 5-min epoch) and degree of spontaneous seizure activity (number and duration of focal versus generalized spikes and spike trains and behavioral seizure correlates). Post-kindling records in each cat were divided into two groups (n=1 record each) based on higher or lower spontaneous EEG and behavioral seizure activity and compared to pre-kindling records. We found: (1) before and after kindling, NE and 5-HT but not DA concentrations were significantly lower in sleep than waking at both sites; (2) after kindling, each cat showed cyclic patterns, as follows: (a) higher NE, 5-HT and DA concentrations accompanied increased seizure activity with delayed sleep onset latency and increased sleep fragmentation (reduced sleep state percentages, number of epochs and/or epoch duration) in one recording versus (b) lower monoaminergic concentrations accompanied reduced seizure activity, rapid sleep onset and reduced sleep disruption in the other recording. The alternating, post-kindling pattern suggested "rebound" effects which could explain some controversies in the literature about chronic effects of kindling on monoamines and sleep-waking state patterns.

Monoamines and seizures: microdialysis findings in locus ceruleus and amygdala before and during amygdala kindling.

We used microdialysis to determine extracellular concentrations of norepinephrine (NE), dopamine (DA) and serotonin (5-HT) before and during a 1-day amygdala kindling paradigm. Subjects were young cats (<1 year old; n=8; 6 female, 2 male). Consecutive 5-min samples (2 microl/min infusion rate) were obtained from left amygdala and ipsilateral locus ceruleus complex (LC) under 3 experimental conditions lasting 1-h each (n=12 samples per cat per condition): (1) just before amygdala stimulation (baseline), (2) during focal afterdischarge (AD) and (3) during generalized AD. ADs were elicited by electrical stimulation applied to establish thresholds immediately before dialysate collection as well as during each sample collected in focal vs. generalized AD conditions. Sample concentrations were time-adjusted to correspond with sleep vs. waking state and/or focal vs. generalized ADs. Seizure activity was indexed by AD threshold (mA) and duration (s) as well as number and duration of specific clinically evident (behavioral) seizure manifestations. Main results were: (1) Lower baseline concentrations (fmoles per sample) of NE, DA and 5-HT correlated with subsequent increases in duration of focal and generalized AD as well as number of behavioral seizure correlates. (2) When compared to baseline levels, NE, DA and 5-HT concentrations significantly increased only in amygdala during focal AD and in both amygdala and LC during generalized AD. (3) NE and 5-HT concentrations were higher than DA at both collection sites and were selectively associated with increased wakefulness throughout the study.

Monoamines and sleep: microdialysis findings in pons and amygdala.

This is the first microdialysis report comparing concentrations (pg/microliter) of norepinephrine (NE), serotonin (5-HT) and dopamine (DA) derived from feline locus ceruleus complex (LC) and amygdala. NE and 5-HT declined progressively from waking to slow-wave-sleep (SWS) and then to rapid-eye-movement (REM) sleep. Concentrations of DA did not change at either collection site across the sleep-wake cycle. We conclude that release of NE and 5-HT release modulates physiologic components related to the sleep-wake cycle, but DA does not.

Parallelizable Bayesian tomography algorithms with rapid, guaranteed convergence.

Bayesian tomographic reconstruction algorithms generally require the efficient optimization of a functional of many variables. In this setting, as well as in many other optimization tasks, functional substitution (FS) has been widely applied to simplify each step of the iterative process. The function to be minimized is replaced locally by an approximation having a more easily manipulated form, e.g., quadratic, but which maintains sufficient similarity to descend the true functional while computing only the substitute. We provide two new applications of FS methods in iterative coordinate descent for Bayesian tomography. The first is a modification of our coordinate descent algorithm with one-dimensional (1-D) Newton-Raphson approximations to an alternative quadratic which allows convergence to be proven easily. In simulations, we find essentially no difference in convergence speed between the two techniques. We also present a new algorithm which exploits the FS method to allow parallel updates of arbitrary sets of pixels using computations similar to iterative coordinate descent. The theoretical potential speed up of parallel implementations is nearly linear with the number of processors if communication costs are neglected.

ML parameter estimation for Markov random fields with applications to Bayesian tomography.

Markov random fields (MRF's) have been widely used to model images in Bayesian frameworks for image reconstruction and restoration. Typically, these MRF models have parameters that allow the prior model to be adjusted for best performance. However, optimal estimation of these parameters(sometimes referred to as hyper parameters) is difficult in practice for two reasons: i) direct parameter estimation for MRF's is known to be mathematically and numerically challenging; ii)parameters can not be directly estimated because the true image cross section is unavailable.In this paper, we propose a computationally efficient scheme to address both these difficulties for a general class of MRF models,and we derive specific methods of parameter estimation for the MRF model known as generalized Gaussian MRF (GGMRF).The first section of the paper derives methods of direct estimation of scale and shape parameters for a general continuously valued MRF. For the GGMRF case, we show that the ML estimate of the scale parameter, sigma, has a simple closed-form solution, and we present an efficient scheme for computing the ML estimate of the shape parameter, p, by an off-line numerical computation of the dependence of the partition function on p.The second section of the paper presents a fast algorithm for computing ML parameter estimates when the true image is unavailable. To do this, we use the expectation maximization(EM) algorithm. We develop a fast simulation method to replace the E-step, and a method to improve parameter estimates when the simulations are terminated prior to convergence.Experimental results indicate that our fast algorithms substantially reduce computation and result in good scale estimates for real tomographic data sets.