Mm For Sites Research Articles

Effect of soft tissue volume on midfacial gingival margin alterations following immediate implant placement in the esthetic zone: a 1-year randomized clinical and volumetric trial.

The current trial evaluated the midfacial gingival margin changes, volumetric, radiographic and clinical alterations 1-year following immediate implant placement with customized healing abutment (IIP + CHA) either solely, or in combination with xenograft (IIP + Bonegraft) or with connective tissue grafting (IIP + CTG) at sites with thin labial bone in the esthetic zone. Thirty-nine non-restorable maxillary teeth indicated for extraction in the esthetic zone were included. Participants were randomly assigned into three equal group; IIP + Bonegraft (Control), IIP + CTG and IIP + CHA. Midfacial gingival margin changes(mm) as primary outcome, labial soft tissue contour change(mm), interdental tissue height changes and total volume(mm3) were assessed. Amount of bone labial to the implant and crestal bone level changes were also recorded. All outcomes were measured 1-year post-operative. The midfacial gingival margin changes demonstrated a significant difference (P ≤ 0.05) between the groups showing -0.98, -0.74 and -1.54mm in sites treated with IIP + Bone graft, IIP + CTG and IIP + CHA respectively after1-year. While labial soft tissue contour change (mm), total volume (mm3) and distal interdental tissue height changes (mm) revealed a significant difference after one-year between the studied groups, yet mesial interdental tissue height changes showed no difference (P > 0.05). Both IIP + Bone graft and IIP + CHA groups revealed a significant positive correlation between the total volume loss (mm3) after 1 year and mid-facial gingival margin changes (P ≤ 0.05). However, no significant correlation was observed in the IIP + CTG group (P = 0.63). CBCT measurements showed a significant difference in crestal bone changes between the three groups (P ≤ 0.05), yet, there was no significant difference regarding mean amount of bone labial to the implant(P > 0.05). This investigation suggests that the mere presence of CTG simultaneous with IIP in the anterior maxilla reduced the midfacial gingival margin alterations (mm), besides, CTG decreased the overall volume loss (mm3) by 5-folds compared to the other studied groups after one year. Meanwhile, using CHA alone with IIP failed to maintain the peri-implant soft tissues contour. The current trial was retrospectively registered at Clinical trials.gov (ID: NCT05975515, Date: 27-July-2023).

Systematic Analysis of Lower Second Molar Periodontal Health after Autogenous Dentine Graft from Wisdom Tooth Extraction

Introduction: Postoperative complications stemming from lower wisdom tooth extractions are often overshadowed by the immediate need to address pain and existing disease. Nevertheless, an emerging body of evidence suggests the importance of preventing potential periodontal damage to the adjacent second molar resulting from the extraction surgery. To avert periodontal complications involves promoting bone formation within the extracted socket defect. Allogenic and artificial bone, as well as the patient’s bone, have conventionally filled the osseous void post-surgery. These approaches are costly and may extend the patient’s recovery. An Autogenous Dentine Graft (ADG), derived from the recently extracted wisdom tooth, presents, as a particulate with osteoconductive and osteoinductive properties, is ideal for preserving bone integrity. This review assesses the available evidence supporting the use of ADG in safeguarding against periodontal morbidity resulting from the surgical extraction of a lower third molar. Materials and methods: A systematic review of the literature was conducted, focusing on the periodontal health of the second molar and the bone height of the osseous defect postwisdom tooth extraction. Out of 76 identified articles, four studies were selected for the review. Results: Three months post-surgery, the mean periodontal probing depth distal to the second molar was 4.7mm in control sites and 2.83mm in sites treated with ADG. Over 12 months, the mean bone height exhibited a negative loss of 1.25mm in control sites and a positive gain of 0.9mm in sites treated with ADG. Conclusion: Presently, there is insufficient evidence to unequivocally support the use of an autogenous dentine graft following the surgical extraction of a wisdom tooth. However, early results are promising, and given the biocompatibility of a material derived from the patient, ADG is considered a safe option for patients at high risk of an osseous defect. Further research is needed to substantiate these findings and guide clinical decision-making.

Comparative Evaluation of Injectable Platelet Rich Fibrin (I-PRF) with DFDBA and Titatium Prepared Platelet Rich Fibrin (T-PRF) with DFDBA In The Treatment of Infrabony Defects In Chronic Periodontitis Patients - A Clinico-Radiographical Study

Objectives: The main objective of this study was to evaluate the efficacy of Titanium prepared platelet-rich Fibrin (T-PRF) and Injectable Platelet Rich Fibrin (I-PRF) with demineralized freeze-dried bone allograft (DFDBA) in order to improve the clinical and radiographic results obtained in treatment of periodontal infrabony defects.
 Materials and Methods: This split-mouth randomized controlled clinical trial was conducted on 30 subjects with two comparable bilateral infrabony defects. Plaque Index(PI), Gingival Index(GI) Clinical attachment level (CAL), Periodontal Pocket depth (PD), as well as radiographic parameters IOPA including the radiographic defect size, were measured at six months post-operatively.
 Results: The mean reductions in PD and CAL were 4.0±0.77 mm and 2.5±0.68 mm in sites treated with I-PRF+DFDBA, respectively (P<0.05); these reductions were 4.2±0.86 mm and 3.1±0.62 mm, respectively in T-PRF+DFDBA group (P<0.05). Radiographic evaluation revealed reduction in the radiographic defect size in the I-PRF+DFDBA and T-PRF+DFDBA sites. Statistically, there were no significant differences between the two treatment modalities.?
 Conclusion: This study showed that both treatments resulted in significant improvement in the probing depth reduction, clinical attachment level gain and radiographic size of the infrabony defect at six months after surgery. I-PRF with DFDBA membrane in treatment of infrabony osseous defect showed more defect fill followed by T- PRF along with DFDBA membrane.

Influence of local anesthesia on the outcomes of non-surgical periodontal treatment.

BackgroundThere is limited evidence of the effects of local anesthesia (LA) on outcomes of non-surgical periodontal treatment (NSPT), in particular among the Chinese. This retrospective cohort study aimed to evaluate the effects of LA on short-term treatment outcomes of NSPT and to determine under what circumstances LA should be prescribed to improve these outcomes.MethodsData from periodontal examinations of 3980 patients were used. The data were from 3-month re-evaluation records of an electronic periodontal charting record system in the Department of Periodontology of Peking University School and Hospital of Stomatology from June 2008 to January 2015. Descriptive analyses included changes in probing depth (PD) and the Mazza bleeding index (BI). Two-level (patient and tooth) logistic regression models and three-level (patient, tooth, and site) linear regression models were constructed to analyze the influence of LA on PD for all teeth/sites and teeth/sites with an initial PD ≥ 5 mm. Decreases in PD and BI at sites under LA using the initial PD were also compared.ResultsA significantly higher mean decrease in PD after NSPT was found in the LA group than in the no local anesthesia (NLA) group (0.98 vs. 0.54 mm, t = 24.12, P < 0.001). A significantly higher probability of decreases was found in the LA group in BI (percentages of teeth with BI > 1 and BI > 2) for all teeth (16.7% vs. 13.8%, t = 3.75, P < 0.001; 34.7% vs. 28.1%, t = 6.73, P < 0.001) and PD for teeth with PD ≥ 5 mm (32.3% vs. 17.3%, t = 28.48, P < 0.001). The difference in PD between the LA and NLA groups increased as the initial PD increased. The difference between the two groups was 0.12 to 0.22 mm for sites with a baseline PD < 7 mm; however, it increased to 0.41 to 1.37 mm for sites with a baseline PD ≥ 7 mm.ConclusionsLA improved the decrease in PD after NSPT. Root debridement at sites with initial PD ≥ 7 mm should be performed under routine LA.

Spatial and Temporal Variability of the Impacts of Pinyon and Juniper Reduction on Hydrologic and Erosion Processes Across Climatic Gradients in the Western US: A Regional Synthesis

Pinyon (Pinus spp.) and juniper (Juniperus spp.) woodlands are an important vegetation type in the Great Basin, Colorado Plateau, and southwestern desert regions of the western US that is undergoing substantial changes associated with land management, altered disturbance regimes, and climate change. We synthesized literature on the ecohydrologic impacts of pinyon and juniper tree reductions across plot to watershed scales, short- and long-term periods, and regional climatic gradients. We found that the initial plot- to hillslope-scale ecohydrologic and erosion impacts of tree reduction on pinyon and juniper woodlands by fire, mechanical tree removal, or drought depend largely on: (1) the degree to which these perturbations alter vegetation and ground cover structure, (2) initial conditions, and (3) inherent site attributes. Fire commonly imparts an initial increased risk for hillslope runoff and erosion that degrades over time with vegetation and ground cover recovery whereas tree reductions by mechanical means pose fewer initial negative ecohydrologic impacts. Tree reduction by either approach can enhance understory vegetation and improve site-level ecohydrologic function over time, particularly on sites with an initially favorable cover of native herbaceous vegetation and a cool-season precipitation regime. Understory vegetation and ground cover enhancements appear to increase ecohydrologic resilience of some woodland communities to disturbances such as drought, fire, and insect infestations. In contrast, intensive land use, prolonged drought or repeated burning associated with invasions of fire-prone grasses can propagate long-term site degradation through persistent elevated runoff and erosion rates. Our synthesis suggests the annual precipitation requirement for increases in plot- to hillslope-scale soil water availability for herbaceous enhancement through tree removal likely ranges from 200–400 mm for sites in the Great Basin and northern Colorado Plateau (cool-season precipitation regimes), and, although suggested with great uncertainty, likely exceeds 400 mm for woodlands with rain-dominated precipitation regimes in the southwestern US. Overall, literature is inconclusive regarding tree reduction impacts on watershed-scale changes in groundwater and streamflow. To date, there is little evidence that drought-related changes to vegetation in pinyon and juniper woodlands substantially affect watershed-scale water availability and streamflow at the annual time scale. Our synthesis identifies key knowledge gaps to overcome in improving understanding of the ecohydrologic and erosion impacts of broadly occurring pinyon and juniper tree reductions in the western US.

Osmoregulation of the resident estuarine fish Atherinella brasiliensis was still affected by an oil spill (Vicuña tanker, Paranaguá Bay, Brazil), 7 months after the accident

An oil tanker loaded with methanol and bunker oil has exploded in November 2004 in Paranaguá Bay, in front of Paranaguá Harbor, southern Brazil. In order to investigate the chronic effects of an oil spill on a resident estuarine fish, the Brazilian silverside Atherinella brasiliensis was sampled 1, 4, and 7 months after the spill, from 2 sites inside Paranaguá Bay, and also from a reference site inside nearby Guaratuba Bay, non-affected by the spill. Increases in plasma osmolality (reaching ~ 525 mOsm/kg H 2O, or ~ 70% above values in reference fish) and chloride (reaching 214 mM in site C, or ~ 51% above values in reference fish) were detected 4 months after the spill, in parallel with branchial carbonic anhydrase inhibition (to 56% of the activity measured in reference fish) in silversides obtained from the contaminated sites. Plasma cortisol concentration increased progressively in samples from fish obtained 4 (462 ng/mL) and 7 (564–650 ng/mL) months after the spill, when compared to values in reference fish (192 ng/mL). Osmoregulation of a resident estuarine fish is still affected by an oil spill, months after the accident. It is, thus, a sensitive tool for the evaluation of the chronic effects of oil spills inside tropical estuarine systems, and A. brasiliensis is proposed as an adequate sentinel species for monitoring protocols.

Assessing the accuracy of predicted ocean tide loading displacement values

The accuracy of ocean tide loading (OTL) displacement values has long been assumed to be dominated by errors in the ocean tide models used, with errors due to the convolution scheme used considered very small (2–5%). However, this paper shows that much larger convolution errors can arise at sites within approximately 150km of the coastline, depending on the method used to refine the discrete regularly spaced grid cells of the ocean tide model to better fit the coastline closest to the site of interest. If the local water mass redistribution approach is implemented, as used in the OLFG/OLMPP software recommended in the IERS 2003 conventions, OTL height displacement errors of up to around 20% can arise, depending on the ocean tide model used. Bilinear interpolation only, as used in theSPOTL and CARGA softwares for example, is shown from extensive global and regional comparisons of OTL displacement values derived from the different methods and softwares to be more appropriate. This is verified using GPS observations. The coastal refinement approach used in the OLFG/OLMPP software was therefore changed in August 2007 to use bilinear interpolation only. It is shown that with this change, OTL displacement values computed using OLFG/OLMPP, SPOTL and CARGA invariably agree to the millimetre level for coastal sites, and better than 0.2mm for sites more than about 150km inland.

Bone resorbing activity and cytokine levels in gingival crevicular fluid before and after treatment of periodontal disease.

The aim of the present study was to investigate bone resorption activity (BRA), interleukin-1 alpha (IL-1 alpha), IL-1 beta and interleukin-1 receptor antagonist (IL-1ra) in gingival crevicular fluid (GCF) in sites with no signs of periodontal disease and in sites with horizontal or angular loss of periodontal bone. These assessments were performed before and after periodontal treatment. GCFs were collected from 10 individuals with filter strips from two healthy sites and four sites with deep pathological periodontal pockets, two of which showed horizontal bone loss and two with angular bone loss. All diseased pockets were treated with flap surgery and systemic Doxyferm. Twelve months later GCF was collected again and treatment outcome evaluated. BRA in GCFs was assessed in a bone organ culture system by following the release of (45)Ca from neonatal mouse calvariae. The amounts of IL-1 alpha, IL-1 beta and IL-1ra in GCFs were quantified by enzyme-linked immunosorbent assay (ELISA). Treatment resulted in reduction of pocket depths with 3.5+/-0.5 mm in sites with angular bone loss and 2.8+/-0.3 mm in sites with horizontal bone loss. Initially, BRA, IL-1 alpha, IL-1 beta and IL-1ra were significantly higher in GCFs from diseased sites compared with healthy sites. No differences in BRA and cytokine levels were seen between GCFs from pockets with horizontal and angular bone losses. The levels of IL-1 alpha, IL-1 beta and IL-1ra were significantly reduced after treatment of diseased pockets. Pocket depths were significantly correlated to BRA only in pre-treatment sites with angular bone loss. BRA was correlated to Il-1 alpha, IL-1 beta, but not to IL-1ra, in diseased sites with angular bone loss, before and after treatment. The reductions of BRA in the individual sites, seen after treatment, were not correlated to the reductions of Il-1 alpha, IL-1 beta or IL-1ra. These data show that BRA and cytokine levels are increased in GCFs from sites with periodontal disease and that periodontal treatment results in reduction of the cytokines. Our findings further indicate that IL-1 alpha and IL-1 beta play important roles for the BRA present in GCFs, but that other factors also contribute to this activity.

Saprotrophic invasion by the soil‐borne fungal plant pathogen Rhizoctonia solani and percolation thresholds

In this paper we distinguish between invasive and noninvasive (finite) saprotrophic spread of the soil‐borne fungal plant pathogen, Rhizoctonia solani amongst discrete sites of nutrient resource. Using simple concepts of percolation theory, we predict the critical threshold distance, associated with a threshold probability, between donor (colonized) and recipient (uncolonized) nutrient sites at which R. solani can spread invasively by mycelial growth through a population of nutrient sites on a lattice. The critical distance for invasive spread is estimated from colonization profiles derived from placement experiments that summarize the probability of colonization with distance between replicated pairs of colonized and uncolonized sites. Colonization profiles were highly nonlinear, decaying sigmoidally with distance. Thresholds for invasive spread were predicted at inter‐site distances of 8.1 mm and 11.8 mm for sites of low and high nutrient agar, respectively. In population experiments with inter‐site distances below the predicted thresholds, the spread of the fungus was invasive in all replicates. At large distances (&gt;10 mm for low, and &gt;14 mm for high nutrient sites) the spread of the fungus was always finite, with the proportion of finite replicates decreasing sharply close to the percolation threshold. Invasive spread did not depend on the furthest extent of growth of the fungus but on distances predicted by the percolation thresholds. Invasive spread of the fungus is also examined in a more natural and variable, nonsterile system involving the growth and colonization of a lattice of poppy seeds over sand. The system is characterized by a decay in the probability of colonization between older poppy seeds, which effectively ‘quenches’ saprotrophic spread. Hence in the population experiments with poppy seeds all growth was ultimately finite. The threshold distance, corresponding to the critical percolation probability for invasive growth changed from 18 mm to 4 mm over 21d leading to a switch from invasive to finite growth. We conclude that percolation theory can be used to link the growth of individual mycelial colonies to the formation of patches that result from the colonization of particulate organic matter. The nonlinearity of the colonization profiles combined with the presence of a percolation threshold means that small changes in the distance between nutrient sites can result in large differences in final patch size. The rapid decay of particulate organic matter in a more natural system can have a profound effect on the dynamics of colonization, restricting saprotrophic invasion of the soil. The consequences of invasion thresholds for colony growth of saprotrophic and parasitic fungi in dynamical systems are briefly discussed.

Water use by Eucalyptus tereticornis stands of differing density in southern India.

We studied water use by Eucalyptus tereticornis Sm. in two plantations, differing in tree density (1800 stems ha(-1) at Site I and 1090 stems ha(-1) at Site II), in different years. At both sites, stomatal conductance, predawn and midday water potentials and microclimate were measured and used to estimate hourly transpiration by the Penman-Monteith equation. Growth in girth was also measured. Stomatal conductance was closely correlated with atmospheric vapor pressure deficit (D); however, stomata did not close completely even at high D ( approximately 5.0 kPa). Midday leaf water potentials did not fall below -2.0 MPa during any part of the year at either site. Predawn leaf water potentials were greater than -0.25 MPa during the postmonsoon period, but declined to -0.7 MPa at Site I during the premonsoon period. Transpiration estimates ranged from 0.6 to 1.2 mm h(-1) at Site I and from 0.2 to 0.6 mm h(-1) at Site II. The extrapolated transpiration values for the rain-free days of the year were 1563 mm and 853 mm for Sites I and II, respectively. Growth in girth was negligible during the premonsoon period. Photosynthesis was not affected by the minor water stress that developed during the premonsoon period.

901-61 Localization of the Return Pathway in Ischemic Ventricular Tachycardia by Diastolic Potential Mapping

Successful treatment of ischemic VT, including by catheter ablation, requires accurate interpretation of the local electrograms. Diastolic potentials may be recorded over a wide area of the endocardium. This study investigated the relationship of the return pathway in VT to the area displaying diastolic activity. 78 VTs in 30 patients were mapped endocardially at time of surgery. Complete return pathways were seen in 17 VTs of 10 patients. The return pathway was defined by tracking diastolic potentials from the earliest diastolic signal towards the site of VT origin. Conduction time over the return pathway represented the diastolic interval. The area of diastolic activity was determined by calculating the area enclosed by electrodes showing diastolic potentials from an inflated endocardial balloon. The mean return pathway conduction time was 90 ± 31 ms (range 40-140 ms). Mean diastolic interval was 64 ± 23 ms Irange 30-115 ms). The mean area over which diastolic activity could be seen was 317 ± 255 mm 2 (range 28-920 mm 2 ). In all 17 VTs, diastolic activity was seen within 15 mm of site of origin, and this represented an area of 98 ± 65 mm 2 (range 28-170 mm 2 ). 62% local electrograms within 15 mm of site of origin showed a diastolic potential to QRS interval &lt; 70 ms. All patients with such a pattern were cured by surgery, but 2 of 4 patients with diastolic potential to QRS interval ≥ 70 ms had VT recurrence. VT cycle length correlated with the conduction time of return pathway (R = 0.765, p = 0.0002), but not with the area of the return pathway. 1) Region exhibiting diastolic potentials was far greater than the return pathway per se. 2) Characterization of the timing of diastolic potentials relative to the QRS complex helps to identify critical portions of the return pathway close to the VT site of origin. 3) Such analysis may differentiate critical areas of the return pathway from bystander regions. 4) These observations may help direct radio-frequency ablation in the catheter laboratory.

Bone formation utilizing titanium reinforced barrier membranes

Advances in bone reconstructive techniques have increased the indications for implant placement in sites previously thought to be unsuitable. This clinical study evaluated a new surgical technique for the treatment of a variety of localized bone defects in four patients utilizing a titanium-reinforced membrane. The membrane material was developed to maintain a large protected space between the membrane and the bone surface without the need for a supportive device. Healing was uneventful in all sites, and the membranes were retrieved after 6 to 12 months. No residual defects were noted, resulting in an average change of implant exposure of 8.2 +/- 2.3 mm for sites with buccal dehiscences and from 5 to 6 mm ridge enlargement in localized bone defects. The quality of the regenerated tissue under the titanium-reinforced membrane appeared as bone structure with a superficial fibrous layer. This fibrous layer was more pronounced in sites treated with a membrane alone but was more than compensated by the quantity of new bone under the soft tissue. The results demonstrated that the use of a reinforced membrane appears to be a viable alternative for the clinical treatment of non-space-maintaining implant/bone defects. Further clinical and experimental investigations are recommended.

A Role for Antibiotics in the Treatment of Refractory Periodontitis.

Refractory periodontitis is considered by many investigators to be a separate disease entity that is descriptive of a particular patient who has multiple sites, rather than a few individual sites, that do not respond to conventional periodontal treatment modalities. Such patients continue to demonstrate loss of attachment and alveolar bone despite frequent periodontal treatment which includes surgical intervention, scaling and root planing, and often systemically-administered tetracycline. Controlled clinical studies have demonstrated that both clindamycin-hydrochloride and amoxicillin/clavulanate potassium (Au) are beneficial when used in conjunction with periodontal scaling. Gordon et al. found improvements in attachment levels, inflammation, suppuration, and a decrease in pocket depths for up to 2 years following a 7-day course of Clindamycin given in conjunction with a full-mouth scaling. The incidence of disease activity decreased from an annual rate of 8% of all sites prior to antibiotic treatment to 0.5% after treatment. Magnusson, reporting on a similar group treated with a 14-day course of Au, found an average loss of attachment of 2.2 mm and an increase in pocket depth of 1.5 mm in sites demonstrating disease progression prior to antibiotic treatment. At 3 months post-antibiotic therapy, these sites had regained an average of 2 mm of attachment and pocket depths had decreased an equivalent amount. Both attachment levels and pocket depths remained relatively stable for up to 12 months post-therapy. In an ongoing study, 30 subjects with refractory Periodontitis were treated with either Clindamycin or Au in conjunction with scaling or scaling plus a placebo. Prior to antibiotic treatment, but while being scaled at 3-month intervals, sites with disease activity lost an average 2.4 mm of attachment. At 3 months post-treatment, the clindamycin-treated group showed an average gain of 2.1 mm, the Au-treated group gained 1.9 mm, and the scaling group gained 1.4 mm in attachment. The clindamycin group remained relatively stable for up to 21 months and the Au group remained stable for about 15 months without additional treatment. Five of the 6 subjects treated with scaling alone required additional treatment within 9 months. Preliminary analyses have indicated that at least two patterns or rates of attachment loss may be associated with refractory periodontitis and that each pattern may be indicative of a different microflora. The pattern associated with a relatively rapid loss of attachment was characterized by a Gram-negative flora which contained spirochetes, P. intermedia, and Fusobacterium species. A slow, continuous rate was associated with a predominantly Gram-positive flora containing a high proportion of S. intermedius and/or a S. intermedius-like organism. J Periodontol 1993; 64:772-781.

Impairment of the inferior alveolar nerve after sagittal split osteotomy

The incidence and degree of neurosensory disturbance of the inferior alveolar nerve, as well as its recovery course, were studied on 46 sides in 23 patients who had undergone bilateral sagittal split osteotomies, by means of subjective symptoms, light touch, anaesthesiometer and two-point discrimination. The degree of disturbance was classified into mild, moderate and severe grades by the threshold pressure shown in tests with the anaesthesiometer. The disturbance, which was almost exclusively limited to mild (37%) and severe (28%) grades, was observed in 67% of the sample at one week. The disturbance disappeared completely within one to three months postoperatively in most sites with mild disturbance, and within three months to one year in half of the severely affected sites. Although the recovery was delayed in the other half of the severely disturbed sites, the disturbance was of mild grade at one and a half years. The overall incidence of disturbance at one year was 15%. Computed tomographic examination of the ascending ramus showed that the narrowest width between the mandibular canal and the buccal cortical plate ranged from 0 mm to 3.2 mm with a mean of 1.6 +/- 0.9 mm (SD) and it was less than 1.2 mm in 91% of sites with a severe grade disturbance, whereas it was distributed in a range of 0.9 mm to 3.2 mm in sites with no disturbance or with mild or moderate disturbance. The importance of preoperative computed tomography to indicate the location of the mandibular canal and the use of a thin cement spatula for the osteotomy was stressed, to avoid or reduce postoperative development of neurosensory impairment.