Marginal adaptation of mineral trioxide aggregate (MTA) compared with amalgam as a root-end filling material: a low-vacuum (LV) versus high-vacuum (HV) SEM study

AIM: To compare the marginal adaptation of mineral trioxide aggregate (MTA) or amalgam root-end fillings in extracted teeth under low-vacuum (LV) versus high-vacuum (HV) scanning electron microscope (SEM) viewing conditions. METHODOLOGY: Root-end fillings were placed in 20 extracted single-rooted maxillary teeth. Ten root ends were filled with MTA and the other 10 root ends were filled with amalgam. Two 1 mm thick transverse sections of each root-end filling were cut 0.50 mm (top) and 1.50 mm (bottom) from the apex. Gap size was recorded at eight fixed points along the dentine-filling material interface on each section when uncoated wet (LV wet (LVW)) and dry under LV (0.3 Torr) in a JEOL JSM-5800 SEM and backscatter emission (LV dry uncoated (LVDU)). The sections were then air-dried, gold-coated and gap size was recorded once again at the fixed points under HV (10(-6) Torr; HV dry coated (HVDC)). Specimen cracking, and the size and extent of the crack were noted. RESULTS: Gap sizes at fixed points were smallest under LVW and largest under HVDC SEM conditions. Gaps were smallest in MTA root-end fillings. A General Linear Models Analysis, with gap size as the dependent variable, showed significant effects for extent of crack in dentine, material and viewing condition (P = 0.0001). CONCLUSIONS: This study showed that MTA produced a superior marginal adaptation to amalgam, and that LVW conditions showed the lowest gap size. Gap size was influenced by the method of SEM viewing. If only HV SEM viewing conditions are used for MTA and amalgam root-end fillings, a correction factor of 3.5 and 2.2, respectively, may be used to enable relative comparisons of gap size to LVW conditions.     

An investigation of post-operative morbidity following iliac crest graft harvesting

OBJECTIVE: A study which examined the morbidity experienced by patients who underwent iliac crest bone graft procedures. DESIGN: A post-operative questionnaire was forwarded to patients who underwent iliac crest bone graft procedures at a single centre. SUBJECTS: One hundred and fourteen patients underwent iliac crest bone grafts for intra-oral augmentation. RESULTS: Ninety-eight patients (80%) returned post-operative questionnaires. Eighty of the 98 (81.6%) patients suffered post-operative pain with 70% of patients being pain-free after four weeks. However, 10% of patients experienced pain for more than 16 weeks. Eighty-five (86.7%) patients were able to walk without any difficulties six weeks post-operatively. Gait disturbance was not related with age, however there was a significant association between pain and disturbance of gait (P< 0.001). Twenty two patients required the use of a walking stick and the use of such aids varied from 0.5 to 26 weeks. Women used walking aids for longer periods than men (P< 0.05). Twenty five patients had altered sensation with about half of them experiencing altered sensation in the distribution of the lateral femoral cutaneous nerve. Other morbidities included deformity at the hip site (2.4%), haematoma (2.4%), infection (3.2%), stress fracture (4.1%) and meralgia paraesthetica in one patient. Despite the above morbidities, 82 patients were willing to undergo the same procedure again and 89 patients would recommend the procedure to their relatives and friends. CONCLUSION: This study demonstrates considerable morbidity following anterior iliac crest bone harvest for intra-oral augmentation. Clinicians referring patients for such bone graft procedures must be aware of the above morbidities so that any patients referred for such procedures are fully informed.     

Analysis of periodontal risk profiles in adults with or without a history of myocardial infarction

BACKGROUND: An association between periodontitis and cardiovascular diseases has been suggested. AIMS: To study whether a combination of clinical variables in a functional risk diagram enhanced the ability to differentiate between subjects with or without an immediate history of acute myocardial infarction (AMI). MATERIAL AND METHODS: A functional periodontal pentagon risk diagram (PPRD) with five periodontal risk vectors was created. The surface of individual PPRDs was calculated using data from 88 subjects with recent AMI and 80 matched control subjects with no history of AMI. RESULTS: Age, gender, number of remaining teeth (mean value: 21.1 versus 21.6 teeth), smoking status, and pocket probing depth (PPD) distribution did not differ by group. Gingival recession was greater in control subjects (mean difference: 5.7, SD: +/- 1.9, p<0.01, 95% CI: 1.8-9.6). Bone loss > or = 4.0 mm was at all levels studied was significantly greater in subjects with AMI and bone loss > or = 50% (> or = 4 mm) was the best individual predictor of AMI (beta = 2.99, p < 0.000, 95% CI: 7.5-53.4). Only PPRD scores were associated with AMI status when factors not included in the PPRD were studied (beta = 22.1, SE: 5.9, p < 0.0001, 95% CI: 10.3-33.7). The best association between AMI status and study variables was the combination of > or = 4 mm of bone loss > or = 50%, proportion of bleeding on probing (%BOP), %PPDs > or = 6 mm, and tooth loss (Nagelkirke r2 = 0.46). CONCLUSIONS: The combination of five periodontal parameters in a PPRD added predictive value, suggesting that comprehensive data should be used in studies of associations between periodontitis and heart diseases. Radiographic evidence of bone loss was the best individual parameter.     

Salivary micelles: identification of complexes containing MG2, sIgA, lactoferrin, amylase, glycosylated proline-rich protein and lysozyme

Micelles represent macromolecular structures in saliva and the aim of this study was to identify salivary proteins that occur in these globular particles. Micelles were isolated from whole saliva (WS) collected from three individuals and analysed in different experiments. Samples were subjected to polyacrylamide gel electrophoreses, hydrolysed to determine their amino acid composition and total protein concentration, examined by scanning electron microscopy and examined on Western blots probed with a panel of antibodies directed against salivary proteins. On Coomassie Brilliant Blue stained gels, the banding pattern of whole saliva and micelles was similar but the intensity of bands was quite different. Amino acid analysis confirmed that the amino acid composition of micelles was distinct from that of whole saliva. Scanning electron microscopy showed that micelles exhibit a complex pattern consisting of individual particles or clusters of particles with different sizes and shapes. Micelles contain proteins with high (MG2 and secretory IgA), intermediate (lactoferrin, amylase and glycosylated proline-rich protein (PRP)) and low (lysozyme) molecular weight that were immuno-detected on blots probed with specific antibodies. Micelles represent particulate multicomponent structures in whole saliva that contain a subset of salivary proteins known to be important components of the innate immune system and are likely to play an important role in the maintenance of homeostasis in the oral environment.     

Longitudinal craniofacial growth patterns in patients with orofacial clefts: geometric morphometrics.

OBJECTIVE: To demonstrate craniofacial developmental patterns in repaired cleft lip and cleft palate (CLP). DESIGN: Retrospective, longitudinal. SETTING: Center for Craniofacial Disorders, San Juan, Puerto Rico. SAMPLE: Males aged 9 to 17 years: 13 noncleft (NC) Class I occlusion (NCC1); 13 NC Class III malocclusion (NCC3); 12 CLP Class I occlusion (CLPC1); and 15 CLP Class III malocclusion (CLPC3). MAIN OUTCOME MEASURES: Form changes (ages 10, 13, and 16 years), using finite-element scaling analysis. RESULTS: NCC1, 10 to 13 interval: 30% size increase in upper midface (p <.05), mental region (p <.01), mandibular body (p <.05); 13 to 16 interval: 10% to 35% size increase in bimaxillary region and ramus (p <.01). NCC3, 10 to 13 interval: 10% to 40% size increase in posterior cranial base, upper midface, and mandible (p <.05); 13 to 16 interval: 10% to 30% size increase in bimaxillary region (p <.01), especially ramus. CLPC1, 10 to 13 interval: 10% to 15% size increase in posterior cranial base (p <.01), midface (p <.05), and mandibular ramus (p <.05); 13 to 16 interval: 8% to 20% size increase in upper midface (p <.01), lower midface (p <.05), and mandible (p <.05). CLPC3, 10 to 13 interval: no significant changes; 13 to 16 interval: upper midface and cranial base show nonsignificant size decreases, but ramus showed size increase. CONCLUSIONS: Noncleft and CLP Class 1 occlusion groups show similar craniofacial growth patterns. Noncleft Class III groups show excessive cranial and mandibular growth. Class III malocclusion in CLP patients is associated with clinically deficient craniomaxillary growth. Growth guidance may be indicated in children with CLP with unfavorable craniofacial growth patterns.     

Assessing periodontal disease risk: a comparison of clinicians' assessment versus a computerized tool

BACKGROUND: The authors conducted a study to compare risk scores assigned by subjective expert clinician opinion with quantitative scores generated for the same subjects using the Periodontal Risk Calculator, or PRC. METHODS: The authors assembled a group of 107 subjects and performed standard periodontal examinations. The authors entered the resulting information into the PRC and calculated risk scores for two and four years, assuming no treatment would be performed. Using the same subject records, three groups of expert clinicians assigned risk scores for years 2 and 4. The authors analyzed the data to reveal the extent of interevaluator variation and the level of agreement between expert clinician scores and PRC scores. RESULTS: The extent of variation among scores assigned by individual expert clinicians was greater than the authors had expected. Expert clinicians consistently assigned more subjects to PRC risk group 2 and fewer to risk group 5 than did the PRC. The authors observed very high heterogeneity in the risk scores expert clinicians assigned to patients in each of the PRC-assigned groups. Thus, expert clinicians varied greatly in evaluating risk and, relative to the PRC, they appeared to underestimate periodontitis risk, especially for high-risk patients. CONCLUSIONS AND PRACTICE IMPLICATIONS: The authors' observations suggest that use of risk scores generated for individual patients by subjective expert clinician opinion about risk in periodontal clinical decision making could result in the misapplication of treatment for some patients and support the use of an objective tool such as the PRC. Use of the PRC over time may be expected to result in more uniform and accurate periodontal clinical decision making, improved oral health, reduction in the need for complex therapy and reduction in health care costs.     

Adhesive resin induces apoptosis and cell-cycle arrest of pulp cells

The application of an adhesive resin near or directly over the pulp was shown to induce pulp inflammation and lack of dentin regeneration. We hypothesize that the absence of dentin bridging is due to adhesive-resin-induced apoptosis of cells responsible for pulp healing and dentin regeneration. Mouse odontoblast-like cells (MDPC-23), undifferentiated pulp cells (OD-21), or macrophages (RAW 264.7) were exposed to SingleBond polymerized for 0-40 seconds. Annexin V and propidium iodide assays demonstrated that SingleBond induced apoptosis of MDPC-23, OD-21, and macrophages. The proportion of apoptotic cells was dependent on the degree of adhesive resin polymerization. Adhesive-resin-induced death of pulp cells was associated with activation of the pro-apoptotic cysteine protease Caspase-3. Interestingly, most cells exposed to adhesive resin that did not undergo apoptosis showed cell-cycle arrest. We conclude that an adhesive resin induces apoptosis and cell-cycle arrest of cells involved in the regeneration of the dentin-pulp complex in vitro.     

Image layer characteristics of the PC 1000 (mark II)

The objective of this study was to investigate empirically the image layer characteristics of the PC 1000 Mark II. Radiographs were taken of a lead resolution grid positioned at 1 mm increments along angular intervals of the projected x-ray beam. The receptor was T-Mat G film combined with Lanex Regular Screens. The path of the effective rotation center was determined using a film positioned horizontally at right angles to the slit beam. The vertical magnification factor, horizontal magnification and Distortion Index, corrected for the position of the tomographic layer, were calculated using a reference object placed at various resolution limits of the image layer. The beam projection angle was compared to the average dental arch shape and proximal contact angle. The maximum resolution observed at the central plane of the image layer was 4 lp · mm⁻¹. The image layer width at the 1.5 lp · mm⁻¹ resolution contour varied from 12 mm anteriorly to 41 mm posteriorly. The vertical magnification factor within the image layer showed a linear increase along the beam path from 1.21 to 1.36. The horizontal magnification varied from 1.07 to 1.71, and the Distortion Index from 0.85 to 1.15. The beam projection angulations to the average arch shape ranged from 90° anteriorly to 115° in the premolar segments and 105° in the molar regions. The empirically derived image layer of the PC 1000 Mark II conforms to the shape of the average dental arch and that found using MTF analysis. The spatial resolution attained using a standard receptor is within the acceptable range.     

FRCSEd (Oral and Maxillofacial Surgery): a milestone in the history of Oral and Maxillofacial Surgery in the United Kingdom

The British Association of Oral and Maxillofacial Surgeons (BAOMS) and the Royal College of Surgeons of Edinburgh (RCSEd) have had leading roles in organisation, assessment and improvement of surgical training in the United Kingdom. This was particularly well illustrated by the establishment of the fellowship examination in Oral and Maxillofacial Surgery (FRCSEd, OMFS).