A 20-year historical prospective cohort study of root canal treatments. A Multilevel analysis.

AIM: To evaluate the number of healthy and functional root filled teeth of patients included in a recall programme for at least 20 years. METHODOLOGY: Teeth were root filled by a single specialist following manual canal instrumentation, lateral/vertical compaction of gutta-percha and restored with glass-ionomer cements and bonding system/composite resin. In a large percentage of teeth, a metal-ceramic crown was placed during follow-up. Patients included in the recall programme (n = 130) were blindly assessed both clinically and radiographically (every 2 years) to evaluate clinical symptoms and periapical status (PAI). The following variables were analysed: age, tooth location, tooth type, initial diagnosis, PAI, root filling length and coronal restoration type. Chi-square test and multilevel analysis were performed to detect variables associated with treatment functionality and disease/lesions (P < 0.05). A cumulative teeth survival curve was constructed by means of Kaplan-Meier using extractions as the end-point. RESULTS: At the 20-year recall, 72 patients (31 M, 41 F; mean age 57.7 ± 8.29 years; 196 teeth) completed the follow-up. Thirty-six patients were excluded for medical complications or died before the end of the study. Drop-outs consisted of 22 patients (17%) who did not complete the follow-up. Single metal-ceramic crowns were positioned after 4-6 months in 40% of teeth. Composite restorations were replaced with single metal-ceramic crowns during the follow-up in 53% of teeth after 8-19 years. Of 196 teeth, 155 were classified as Survived (79%), 128 of which (65%) were Healthy (PAI ≤ 2). Thirty-nine teeth (20%) were extracted for nonendodontic reasons. Twenty-nine teeth (15%) were classified as: re-exacerbation (11 teeth; 5.6%) or persistent asymptomatic lesions (18 teeth; 9%). Only two re-exacerbated teeth were extracted. Multilevel analysis confirmed the clinical relevance of tooth type (P = 0.001) on Survived and healthy teeth (P = 0.007). Tooth location (P = 0.0045) and initial diagnosis (P = 0.019) significantly affected only Healthy teeth. CONCLUSIONS: Root filled teeth were more frequently extracted for non-endodontic reasons rather than for endodontic disease. The majority of teeth with adequate root fillings, adequate restorations and included in a recall programme remained functional and healthy for more than 20 years.

Survival and periapical health after root canal treatment with carrier-based root fillings: five-year retrospective assessment.

AIM: This retrospective study explored survival and periapical healing outcomes in teeth root filled with Thermafil obturators. METHODOLOGY: Root canals of 213 teeth (94 subjects, mean age 48 ± 13 years), instrumented with a step-down technique, irrigated with 5% NaOCl and 10% EDTA and filled with Thermafil and AH Plus sealer, were involved in a recall programme. Teeth were retrospectively re-examined after 5 ± 1 years in a controlled environment. Clinical and radiographic data that were collected included the following: preoperative Periapical Index (PAI) score and signs/symptoms, treatment type, root filling length and presence/absence of voids, restoration type, follow-up PAI score and signs/symptoms. Teeth were considered 'healthy' (PAI ≤ 2, no signs/symptoms) or 'diseased' (PAI ≥ 3, signs/symptoms present, retreated, extracted for endodontic reasons). Two PAI-calibrated examiners assessed outcomes blinded to preoperative status. Bivariate and multilevel analyses were performed at level of patient and tooth (α = 5%). RESULTS: Of 213 teeth treated, 187 (88%) survived and 26 were extracted, six (3%) for persistent endodontic infection (considered 'diseased'), and 20 (9%) for root fracture, periodontal disease or coronal fracture (excluded from analysis). Whilst survival was significantly associated with tooth type (P = 0.015), type of treatment (P = 0.012) and pulpal/periapical diagnosis (P = 0.035), none of these variables were substantiated as survival predictors by the multilevel analysis. A total of 164 of 193 teeth (85%) were assessed as 'healthy', with significantly higher (chi-square; P < 0.04) 'healthy' rates for teeth with PAI score ≤2 and root fillings of adequate length. Multilevel analysis identified PAI score ≤2 (P = 0.002) as the only predictor of periapical health. CONCLUSIONS: In this 5 ± 1 year retrospective assessment, survival and healing rates after root canal treatment with Thermafil root fillings were comparable to those previously reported for conventional root filling techniques.

Structural analysis of HyFlex EDM instruments.

AIM: To compare the phase transformation behaviour, the microstructure, the nano-hardness and the surface chemistry of electro-discharge machined HyFlex EDM instruments with conventionally manufactured HyFlex CM. METHODOLOGY: New and laboratory used HyFlex EDM were examined by X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Nano-hardness and modulus of elasticity were also investigated using a maximum load of 20 mN with a minimum of 40 significant indentations for each sample. Raman spectroscopy and field emission-scanning electron microscope (FE-SEM) were used to assess the surface chemistry of HyFlex EDM. HyFlex CM were subjected to the same investigations and used as a comparison. Nano-indentation data were statistically analysed using the Student's t-test. RESULTS: XRD analysis on HyFlex EDM revealed the presence of martensite and rhombohedral R-phase, while a mixture of martensite and austenite structure was identified in HyFlex CM. DSC analysis also disclosed higher austenite finish (Af) temperatures for electro-discharge machining (EDM) instruments. Significant differences in nano-hardness and modulus of elasticity were found between EDM and CM files (P < 0.05). FE-SEM and EDS analyses confirmed that both new EDM and CM files were covered by an oxide layer. Micro-Raman spectroscopy assessed the presence of rutile-TiO2 . CONCLUSIONS: HyFlex EDM revealed peculiar structural properties, such as increased phase transformation temperatures and hardness. Present results corroborated previous findings and shed light on the enhanced mechanical behaviour of these instruments.

Double dye technique and fluid filtration test to evaluate early sealing ability of an endodontic sealer.

OBJECTIVES: The aim of the present study is to evaluate the possible correlation between sealer penetration into dentinal tubules and sealing ability both in presence and absence of smear layer. MATERIALS AND METHODS: Fourteen maxillary central incisors were treated with 5.25 % NaOCl +10 % EDTA to remove the smear layer (SL-free group) or 5.25 % NaOCl without EDTA (SL group). Root canals were filled using #25 Thermafil Obturators with Topseal sealer labelled with 0.1 wt% rhodamine B. Sealing ability was measured as fluid filtration rate with a fluid-flow meter using water supplemented with 0.3 % calcein fluorescent dye. Specimens were sectioned, observed under confocal microscope to co-localize the presence of sealer (rhodamine B labelling) into dentinal tubules and gaps (calcein labelling) into the root canal. The depth of sealer penetration into dentinal tubules and the percentage of sealer penetration around the root canal were measured at 3, 5 and 8 mm from the apex. RESULTS: No significant differences between groups were observed in fluid filtration rate nor in depth of calcein penetration. Sealer penetration depth and percentage into dentinal tubules were not significantly different between groups, except at 8-mm level in absence of smear layer. CONCLUSION: Sealer penetration at 3- and 5-mm levels was not influenced by smear layer while it was significantly reduced at 8-mm level. Fluid filtration rate was not correlated either with depth of calcein penetration nor with sealer penetration into dentinal tubules. CLINICAL RELEVANCE: The sealing ability of Topseal sealer is not affected by presence or absence of smear layer.

HyFlex EDM: superficial features, metallurgical analysis and fatigue resistance of innovative electro discharge machined NiTi rotary instruments.

AIM: To evaluate the surface and microstructural alterations of new and used HyFlex EDM prototypes and to test their fatigue resistance. METHODOLOGY: Fifteen HyFlex EDM prototypes were used for in vitro instrumentation of severely curved root canals. Surface and microstructural characteristics of new and used files were compared by ESEM analysis equipped with energy dispersive X-ray spectrophotometry (EDS) and optical metallographic imaging. Usage-induced degradation was assessed. Thirty additional HyFlex EDM prototypes and 20 standard manufactured HyFlex CM files were subjected to cyclic fatigue tests. Time to fracture was recorded, and results were validated using the Kruskal-Wallis test (α-level 0.05). Fatigued files were analysed by ESEM for fractographic evaluation. RESULTS: Surface and microstructural characterization of EDM prototypes revealed the typical spark-machined surface of a NiTi EDM alloy. No fractures were registered during root canal instrumentation. No evident surface alterations and minor degradation were observed between new and used instruments. The metallographic analysis of new and used files disclosed a homogeneous structure, mostly composed of lenticular martensite grains, and some residual austenite. The cyclic fatigue test showed an increase of fatigue resistance up to 700% on the EDM compared to CM files. CONCLUSIONS: Spark-machined peculiar surface is the main feature of HyFlex EDM. Low degradation was observed after multiple canal instrumentations. Prototypes exhibited surprising high values of cyclic fatigue resistance and a safe in vitro use in severely curved canals.

The use of calcium-silicate cements to reduce dentine permeability.

OBJECTIVE: To evaluate in vitro the effectiveness of different calcium-silicate (CS) cements specifically designed for dentine permeability reduction. DESIGN: Fifty dentine discs were prepared from caries free human molars extracted for surgical reasons. The treatment consisted in applying two different experimental CS cements on dentine surface. Dentine discs treated only with EDTA served as negative control group. Treatment with D-Sense Crystal and Clearfil S(3)-Bond served as positive control groups. After treatment samples were immersed in artificial saliva. The quantitative changes in the hydraulic conductance (i.e. permeability) through dentinal tubules were quantified using a hydrostatic device working at 6.9 kPa. Dentine permeability was measured immediately after EDTA treatment, 10 min and 1 week after treatment application and immersion of dentine samples in artificial saliva. SEM/EDX analyses were performed to obtain qualitative information on dentine morphology and surface deposits. RESULTS: The experimental CS cements reduced dentine permeability immediately after application and also 10 min and 1 week after the immersion of the specimens in artificial saliva. D-Sense Crystal and Clearfil S(3)-Bond showed higher levels of dentine permeability after 1 week of immersion in artificial saliva. CONCLUSIONS: CS cements reduced dentine permeability in vitro even after immersion in artificial saliva, which makes them new valuable candidates for treatment of dentine hypersensitivity in vivo.

The effect of ultrasonic removal of various root-end filling materials.

AIM: To compare residual root-end filling material in apical root-end cavities following their removal with ultrasonic retrotips. METHODOLOGY: Thirty single-rooted teeth were filled with Thermafil and AH Plus sealer. Root-ends were resected at 90 degrees, 3 mm from the apex. Root-end cavities were prepared with diamond burs and ultrasonic retrotips and filled with one of three filling materials: group I: Retro-TC (calcium silicate-based cement), group II: IRM (Dentsply, Germany), group III: Vitrebond (3M ESPE, USA). After 30 days of storage, ultrasonic retrotips were used to remove materials from the root-end cavities. The ultrasonic application time was fixed at 60 s. Polyether impressions and replicas of the root-ends were made. Root apices and replicas were examined by one operator under a scanning electron microscope. Remnants of residual materials were evaluated using a four-level scoring system; fractures, smear layer and exposed dentinal tubules were also examined. RESULTS: Forty per cent of the specimens filled with Retro-TC revealed complete removal of the material with exposure of dentinal tubules, whilst 60% contained residual cement. Twenty per cent of specimens filled with IRM were completely devoid of material, whereas 80% had retained material. Ten per cent of specimens filled with Vitrebond retained a moderate amount of material whilst 90% had substantial retention of the material. Statistically significant differences were found (P < 0.05) amongst the three groups of materials. CONCLUSIONS: Retro-TC was successfully removed in 40% of cases using ultrasonics retrotips for 60 s, whereas IRM and Vitrebond specimens had evidence of retained material in 80% and 90% of all specimens respectively.

Intravenous pulse cyclophosphamide treatment of severe lupus nephritis: a prospective five-year study.

Despite its widespread use, there are only a few published studies of the use of intravenous high dose pulse cyclophosphamide in systemic lupus nephritis. There are few data about the long-term efficacy and safety of this form of therapy. This study evaluates the clinical efficacy, toxicity, and effects on renal morphology of this regimen in patients with severe lupus nephritis followed prospectively over a five-year period. Twenty consecutive patients with severe active lupus nephritis were enrolled in a treatment regimen of six monthly intravenous pulses of cyclophosphamide (0.5 to 1 g/m2) together with high dose corticosteroid therapy which was rapidly tapered. Efficacy was assessed by improvement or stabilization of clinical, serologic and renal functional parameters. Repeat renal biopsies were performed in 15 patients. Potential toxicity related to therapy was documented. Over the first six months of treatment, this regimen resulted in improvement of clinical activity, lupus serology, stabilization of renal function and decreased proteinuria in 19/20 patients. Nephrotic syndrome remitted in 8/10 patients by one year. Over five years of follow-up, there were five treatment failures defined as a doubling of serum creatinine over baseline. At five years, 3 patients required renal replacement therapy. Elevated plasma creatinine at time of first biopsy, degree of proteinuria, histologic activity and chronicity were not statistically correlated with treatment failure. Patients who failed to respond to this treatment were, however, more likely to have diffuse proliferative lupus nephritis (WHO Class IV) lesions on initial biopsy.(ABSTRACT TRUNCATED AT 250 WORDS)

De novo membranous glomerulonephropathy in renal allografts: a report of ten cases and review of the literature.

De novo posttransplantation membranous glomerulonephropathy (MGN) is the most common form of de novo glomerulopathy in renal allografts. The clinical and pathological features of ten patients with de novo MGN were studied and the related literature was reviewed to assess the clinical features, morphologic characteristics, and natural course of this disease. De novo MGN may occur in both living related and cadaveric allografts at any time after transplantation. It presents clinically either as asymptomatic proteinuria or the nephrotic syndrome, a feature of poor prognostic implication. Morphologically, de novo MGN in most instances has distinct differences from idiopathic MGN in native kidneys and is accompanied by varying features of rejection. About 50% of grafts which develop de novo MGN eventually fail. This rather poor outcome may not represent the natural history of de novo MGN per se but rather the consequences of associated chronic rejection. Evidence is presented that many of the cases of so-called de novo MGN may be a complication of transplant glomerulopathy rather than being caused by mechanisms totally independent from rejection.

Interstitial nephritis related to nonsteroidal anti-inflammatory agents and beta-lactam antibiotics: a comparative study of the interstitial infiltrates using monoclonal antibodies.

Acute interstitial nephritis (AIN) is a common pattern of renal injury induced by therapeutic agents. In order to characterize the types of mononuclear leukocytes infiltrating the kidney in drug-induced interstitial nephritis, a panel of monoclonal antibodies (Leu1, Leu3a, OKT8, OKM1, Leu14, OKT17, IL-2) was applied to cryostat sections of 13 renal biopsies (five non-steroidal anti-inflammatory agents (NSAID) (Group I); five beta-lactam antibiotics (Group II), 3 miscellaneous (Group III]. The majority of infiltrating mononuclear leukocytes were Leu1-positive T cells (71.7 +/- 18.7%), followed by monocytes (15.2 +/- 7.7%) and B cells (7.4 +/- 9.1%). Leu3a/OKT8 ratio was 0.954 +/- 0.341. Rare cells reacted with antibody to the interleukin-2 receptor (1.4 +/- 1.2%). No statistically significant differences could be found in the percentages of T lymphocytes, B lymphocytes, monocytes, activated (IL-2+) T cells or Leu3a/OKT8 (helper/suppressor) ratios in the three groups. In Group II, the following pathologic correlations were seen: Leu3a/OKT8 versus interstitial inflammation (R = -0.848), percent Leu3a versus interstitial inflammation (R = -0.818), percent OKT17 versus tubulitis (R = 0.785), percent Leu14 versus tubular atrophy (R = -0.891), and interstitial edema (R = 0.965). Our findings support a role for cellular immune mechanisms in the pathogenesis of AIN related to both NSAIDs and beta-lactam antibiotics.

Myeloma cast nephropathy: immunohistochemical and lectin studies.

Renal disease is a common cause of morbidity and mortality in patients with plasma cell dyscrasia (PCD). We have conducted a systematic study of the formalin-fixed, paraffin-embedded renal tissues from 53 patients with plasma cell dyscrasia, 24 of whom had Bence Jones cast nephropathy (with large casts, often associated with giant cells and polymorphonuclear leukocytes). A battery of 5 immunocytochemical and lectin markers for various segments of the nephron was used [Tetragonolobus lotus, Arachis hypogaea (AH), Tamm-Horsfall protein (THP), epithelial membrane antigen (EMA), and cytokeratin (AE1/AE3)]. In particular, we sought to determine the nature of the intratubular multinucleated giant cells in Bence Jones myeloma cast nephropathy with a variety of epithelial and hematopoietic cell markers. Although tubular epithelial cells stain with their respective markers (whether inflamed, thinned, detached, or adjacent to and lining casts), true intratubular giant cells in PCD were never positive for these tubular markers. In approximately one-third of the cases studied, intratubular and extratubular giant cells stained for several of the seven hematopoietic cell markers employed [i.e., alpha 1-antitrypsin (A1AT), alpha 1-antichymotrypsin (A1ACT), vimentin, and lysozyme], suggesting that giant cells are of hematopoietic origin. The majority of the casts are present in the distal nephron, although some casts were noted in more proximal sites of the nephron. Some larger casts did not stain for THP; smaller casts often showed lamination or stratification of THP staining. Finally, in one-half of the cases, Tamm Horsfall protein (THP) and other distal tubular markers (AH, EMA, AE1/AE3) were found in Bowman's space, almost always in association with interstitial deposits of THP; these markers were virtually never noted in Bowman's spaces of PCD patients without numerous large casts. This suggests that there are communications between distal and proximal nephron, most likely by intraluminal reflux but possibly also through breaks in the tubules and via the interstitium.

Long-term follow-up of patients with lupus nephritis. A study based on the classification of the World Health Organization.

The long-term course of 56 patients with systemic lupus erythematosus who had precisely defined renal histology and carefully assessed clinical status at the time of their initial renal biopsy prior to 1976 was evaluated and analyzed by life-table analysis. The average length of follow-up has now been greater than 10 years since initial biopsy. Patients with mesangial lesions (World Health Organization [WHO] classes IIA and IIB) had a more favorable renal and patient survival at five and 10 years than did patients in the other WHO classes (III, IV, and V). Individual renal histologic features of activity and chronicity when combined into an activity index and a chronicity index did not significantly predict renal survival in this population, nor did the presence of hypertension or renal dysfunction at the time of the initial renal biopsy significantly influence renal or patient survival. Patients with the nephrotic syndrome at initial biopsy had a poorer renal survival than did patients without the nephrotic syndrome. However, patients who experienced a remission of the nephrotic syndrome fared better in terms of both renal and patient survival than did those patients without a remission. By life-table analysis, patient survival was significantly better for patients in whom biopsy was performed after 1973 than for those in whom biopsy was performed prior to that time despite similar clinical features and WHO histology in each group interval. Our data suggest that improved survival for patients in recent studies may relate to better supportive care and more selective use of immunosuppressive therapy in patients with milder forms of lupus nephritis.

Renal lesions in plasma cell dyscrasias: ultrastructural observations.

The renal biopsies from 47 patients with plasma cell dyscrasias were studied by light and electronmicroscopy, and by immunohistochemical methods. This report is primarily concerned with the ultrastructural features of 24 cases of Bence Jones cast nephropathy and of ten cases of light chain deposit disease. In Bence Jones cast nephropathy, crystals derived from light chain proteins were detected in the majority of cases within the casts or in tubular cells and appeared to be related to the "hard" and "fractured" appearance of the casts as well as to the presence of foreign body type giant cells, the latter probably being of monocyte-macrophage origin. In light chain deposit disease, linear deposits of light chain proteins (eight kappa and two lambda) were present in a subendothelial position along the glomerular basement membrane and along the outer aspect of the tubular basement membranes in all cases, quite often in the mesangial matrix, but much less commonly in the interstitium and in the wall of small arteries. The light and electronmicroscopic features of both Bence Jones cast nephropathy and light chain deposit disease can be considered diagnostic for plasma cell dyscrasia. The possible pathogenetic mechanisms of these two different forms of renal involvement are discussed briefly.

Monoclonal antibody identification of infiltrating mononuclear leukocytes in lupus nephritis.

Populations of mononuclear inflammatory cells infiltrating the renal interstitium in LN were studied by means of an avidin-biotin immunoperoxidase technique applied to cryostat sections of 26 renal biopsies (3 WHO class IIb; 4 class III; 8 class IV; 4 class V; 4 class III and V; and 3 class IV and V). The majority of interstitial leukocytes were T cells (mean 65.7 +/- 14.1). The number of cells reactive with OKT8 (47.3 +/- 11.0) exceeded the number of OKT4 positive cells (32.5 +/- 11.3) in 22 of 26 biopsies. Cells reactive with antimonocyte antibodies OKM1 and OKM5 (6.7 +/- 5.9 and 7.9 +/- 5.9, respectively) and B lymphocytes (OKB2 3.9 +/- 3.5) were a minor component of the interstitial infiltrates. Monocytes were the predominant cell type among stained cells in glomerular tufts and crescents. Tissue T4/T8 ratios varied widely (range 0.31 to 1.81), and were less than 1 in 22 of 26 patients. There was no correlation between tissue T4/T8 ratios and simultaneous peripheral blood T4/T8 ratios. Using stepwise multivariate linear regression, tissue T4/T8 ratio was found to correlate highly with renal histologic activity (P less than 0.001) but was not independently predictive of any other histopathologic or clinical variable studied. Mean tissue T4/T8 ratio in LN was significantly lower than that of other glomerular and interstitial diseases studied (P less than 0.001), a finding which may reflect differences in the pathogenesis of renal injury. These findings suggest that local cellular immune mechanisms may be important in the modulation of disease activity in LN.