Pellicle precursor protein crosslinking characterization of an adduct between acidic proline-rich protein (PRP-1) and statherin generated by transglutaminase

Recent work with oral transglutaminase indicated that this enzyme, derived from oral epithelial cells, crosslinked pellicle precursor proteins which may be important in the formation of the acquired enamel pellicle. The purpose of this study was to investigate whether purified acidic PRP-1 can form crosslinks with statherin, and whether such a crosslink is derived from a transglutaminase-catalyzed reaction between glutaminyl and lysyl side-chains, leading to a covalent bond formation. Enzymatic reaction products were analyzed by SDS-PAGE and reverse-phase HPLC. The SDS electrophoretogram revealed a protein band with an apparent molecular weight of 32 kDa, which is consistent with the combined apparent molecular weight of acidic PRP-1 (24 kDa) and statherin (8 kDa). A reaction product isolated by HPLC was characterized by amino acid analysis, which showed a stoichiometry consistent with being an adduct composed of one molecule of acidic PRP-1 and one molecule of statherin. In negative control experiments, it could be shown that this adduct was not detected when the lysines of both substrates were modified by reductive methylation prior to the enzymatic reaction. In addition, amino acid analysis and mass spectrometry confirmed the presence of a gamma-glutamyl-epsilon-lysine dipeptide after enzymatic hydrolysis and the absence of this dipeptide after acid hydrolysis. Analysis of the data obtained indicates that oral transglutaminase is capable of crosslinking acidic PRP-1 and statherin in vitro. In addition, this finding exemplifies the potential of post-secretory processing of salivary proteins, which may represent an additional mechanism to generate new protein species.     

Occlusal contacts during lateral excursions in children with primary dentition

The presence of non-working occlusal contacts in adults is considered abnormal and may initiate parafunctional activity. Few studies have looked for non-working occlusal contacts in children with primary dentition. The purposes of this study were (1) to prove the existence of non-working-side occlusal contacts, and (2) to quantify their area during lateral excursion in children with primary dentition. To achieve this purpose, we developed a measurement system that combined a tracking system for mandibular movements with a three-dimensional digitizer for tooth shape. Ten children were selected for this study. Estimated occlusal contact area of the primary second molar on the non-working side was 0.8 mm2, in contrast to 2.0 mm2 on the working side, at 3.0 mm of movement of the lower incisor. All children examined had some occlusal contacts on the non-working side during the first part of lateral excursion.     

Bilateral variation of the masseteric myotatic reflex and the silent period in young humans

Increased bilateral differences in jaw reflexes have been considered as pathological findings. The aim of this study was to investigate the normal variation between sides in the jaw jerk and the silent period and determine the range of its boundaries, using the present experimental set-up. Electromyographic data were simultaneously recorded from the right and left masseter muscles by surface electrodes, using a computerized recording and analysis system. The reflexes were elicited by chin taps during mandibular rest and at moderate intercuspal clenching in 20 healthy dentate adults (10 males and 10 females) with a mean age of 26 years. The reflexes were always elicited bilaterally and no overall significant differences were observed between sides for occurrence, latency, duration and amplitude of the jaw jerk and for the latency and duration of the silent period (P > 0.05). However, in the individual analysis significant bilateral variation was occasionally recorded, particularly for the jaw jerk at rest and mainly in the amplitude measurements. On the other hand, in the silent period duration measurements individual variation was very limited. Bilateral individual latency differences for the jaw jerk did not exceed 1 ms at rest (x = 0.3 +/- 0.3 ms) and 0.7 ms at clench (x = 0.3 +/- 0.2 ms), while latency differences for the silent period did not exceed 0.8 ms for the early type (x = 0.4 +/- 0.2 ms) and 4.8 ms for the late phase of depression (x= 1.9 +/- 1.7 ms). Bilateral differences for the silent period duration did not exceed 7.1 ms (x = 2.2 +/- 2.3 ms) in the early type (simple + early phase of combined types) and 3.3 ms (x = 1.5 +/- 0.9 ms) in the total duration of the combined types.     

Long-term outcome following treatment of multiple Miller class I and II recession defects in esthetic areas of the mouth

BACKGROUND: Multiple recession defects can be successfully treated using envelope-type coronally advanced flaps. The aim of the present study was to evaluate the long-term (5 years) stability of clinical outcomes achieved with the surgery and the association between patient variables and long-term stability. METHODS: Seventy-three Miller Class I and II gingival recessions affecting 22 young, systemically healthy subjects were treated with coronally advanced flaps with no releasing incisions. All patients were instructed to perform a coronally directed roll technique to minimize the toothbrushing trauma to the gingival margin. The clinical reevaluation was made 1 year after the surgery. At this point, 13 patients took part in a supportive periodontal care program consisting of oral hygiene instructions, control of toothbrushing technique, and professional tooth cleaning every 4 months. The remaining nine patients did not participate and received only sporadic care by general dentists. At 5 years post-surgery, all patients were reexamined. RESULTS: At the 5-year examination, 94% of the root surfaces initially exposed due to gingival recession were still covered with soft tissue, and 85% of the treated recession defects showed complete coverage. Complete root coverage in all recessions was maintained in 15 out of 22 patients (68%). The long-term stability of the soft-tissue margin in the treated sites was significantly influenced by the patient's regular participation in the recall program and the susceptibility to gingival recession in other areas of the mouth. A statistically significant increase of keratinized tissue (0.80 +/- 0.64 mm) was observed between the 1- and 5-year observation visits, and the average increase of keratinized tissue between the baseline and the 5-year follow-up amounted to 1.38 +/- 0.90 mm. This increase was significantly affected by the baseline keratinized tissue (KT) and recession (REC) depth: in particular, the 5-year increase in the amount of keratinized tissue was greater in sites with a greater recession depth and lower amount of keratinized tissue at baseline. CONCLUSIONS: 1) The successful root coverage results obtained with the coronally advanced flap for multiple recession defects were well maintained over the 4-year observation period. 2) Negative patient characteristics such as a lack of compliance with a supportive care program and individual susceptibility to gingival recession were significantly associated with the recurrence in gingival recession. 3) The increase in keratinized tissue height that followed the coronally advanced flap procedure may be attributed to the tendency of the mucogingival line to regain its genetically determined position.     

Locally produced anti-phosphorylcholine and anti-oxidized low-density lipoprotein antibodies in gingival crevicular fluid from aggressive periodontitis patients

BACKGROUND: Sera from patients with periodontal attachment loss contain higher concentrations of IgG anti-phosphorylcholine (anti-PC) than sera from healthy subjects. Furthermore, a large proportion of plaque bacteria bear PC-containing surface antigens, implicating the oral flora as a source of immunogen for anti-PC. Additionally, anti-PC is cross-reactive with a variety of oral bacterial antigens and human antigens such as oxidized low-density lipoprotein (oxLDL). We hypothesized that, if the oral flora is a source of PC antigens, then we should be able to detect local anti-PC and anti-oxLDL production in gingival crevicular fluid (GCF). METHODS: To test this, we collected 66 GCF samples from 15 patients with aggressive periodontitis and examined both the GCF samples and serum samples for their content of IgG anti-PC, IgG anti-LDL, and IgG anti-oxLDL by enzyme-linked immunosorbent assay. We also determined levels of anti-tetanus toxoid (anti-TT) as a non-oral antigen control. Serum and GCF concentrations of serum albumin (HSA) were also determined for use as a dilution marker. A conservative GCF:serum antibody ratio of greater than 1.5 was considered to be evidence of local antibody production. RESULTS: For the non-oral antigen TT, only one out of 62 samples contained locally produced antibody. Eight out of 64 samples (7 from a single subject) demonstrated local production of anti-LDL. In contrast, 28 out of 66 samples demonstrated local production of anti-PC, and 47 out of 66 samples contained locally produced anti-oxLDL. It was observed that A. actinomycetemcomitans strains containing or devoid of PC could absorb anti-oxLDL from human sera. Although there was a correlation between the ratios of anti-PC and anti-oxLDL (Spearman's rho = 0.35, P = 0.0037), local production of both antibodies was found in only 17 out of 65 samples, indicating that these antibodies are not always reflective of reactivity to the same antigens. CONCLUSION: The local production of anti-PC and anti-oxLDL further implicates the oral flora as a source of antigen that may mediate immune reactions of relevance to cardiovascular and other systemic diseases.     

Human periodontal ligament cell responses to recombinant human bone morphogenetic protein-2 with and without bone allografts

BACKGROUND: Recombinant human bone morphogenetic protein-2 (rhBMP-2) has been found to promote the osteoblastic differentiation of human periodontal ligament cells. Its effect depends on the delivery system used. In this study we examined the effect of rhBMP-2 on the proliferation and osteoblastic differentiation of human periodontal ligament cells cultured alone or with 3 different bone allografts. METHODS: The rhBMP-2 effect on cell proliferation and osteoblastic differentiation was examined by measuring [3H] thymidine incorporation and ALPase activity, respectively, on human periodontal ligament (hPDL) cells. Two human demineralized freeze-dried allografts of cortical (DFDBAco) and cancellous (DFBDAca) bone origin and 1 non-demineralized freeze-dried allograft (FDBA) of cancellous bone origin, derived from different tissue banks, were used to evaluate the rhBMP-2 effect on cell osteoblastic differentiation. The measurements were taken on various days. RESULTS: rhBMP-2 decreased hPDL cell proliferation. rhBMP-2 acted on the third day of the process of cell differentiation, had a specific time of action, achieved its peak effect on the fourth and fifth days, and then did not provoke any further effects. The 3 bone allografts were efficiently combined with rhBMP-2. The combination of rhBMP-2 and DFDBAco showed the effect with the longest duration. rhBMP-2, on day 4, made the inactive bone allograft more active while, on the other days, its effect was dependent on the allograft alone. CONCLUSIONS: rhBMP-2 promotes the osteoblastic differentiation of human periodontal ligament cells and decreases cell proliferation. In this study rhBMP-2 in the presence of the bone allografts tested resulted in hPDL cell differentiation.     

Periodontal conditions in patients with juvenile idiopathic arthritis

OBJECTIVE: Our aim was to compare the periodontal conditions in a group of juvenile idiopathic arthritis (JIA) patients with those in a control group of healthy subjects (CTR). MATERIAL AND METHODS: Thirty-two patients with JIA and 24 controls were selected. The measurements used to diagnose periodontal disease included plaque and bleeding scores, probing depths (PDs) and clinical attachment loss (CAL). Laboratory indicators of JIA activity included the erythrocyte sedimentation rate (ESR) and capsule-reactive protein (CRP). The Mann-Whitney test was used to evaluate the data (alpha = 0.05). RESULTS: The mean ages were 15.9 (+/- 2.7) years and 14.7 (+/- 2.3) years for groups JIA and CTR, respectively. The median ESR was 42 mm/h 13 mm/h in the CTR group (p = 0.032) and the median CRP was 1.9 and 0.4 mg/l, respectively (p = 0.001). The prevalence of patients with a proximal attachment loss of 2mm or more in the JIA group was 25% and in controls it was 4.2%. The mean percentages of visible plaque and marginal bleeding were similar in the JIA (54 +/- 22 and 30 +/- 16, respectively) and CTR groups (44 +/- 18 and 29 +/- 11, respectively). The mean percentages of sites with PD > or = 4 mm were significantly higher in the JIA group (3 +/- 4.7) than in the CTR group (0.4 +/- 1.7) (p = 0.012). The mean percentages of sites with proximal CAL > or = 2 mm were 0.7 (+/- 1.4) in the JIA group and 0.001 (+/- 0.2) in the CTR group (p = 0.022). CONCLUSION: Adolescents with JIA present more periodontal attachment loss than healthy controls, in spite of similar plaque and marginal bleeding levels.     

The new dental biology--threat or opportunity?

A clinician argues that the new biology is a threat or an opportunity depending on the perspective practitioners take. New approaches should be seen as extensions of the services dentists can provide patients rather than restrictions. Different parts of the new biology will become available in the office at different times, and will be implemented by general practitioners or specialists, depending on their character. Important innovations in diagnosis and prevention are emerging currently. New relationships with medicine will be forged rather than dentistry becoming part of medicine. Innovations in dental education and continuing education will accelerate the coming changes.     

Effect of four different opalescence tooth-whitening products on enamel microhardness

OBJECTIVES: The purpose was to evaluate the effect of various Opalescence tooth-whitening products on enamel. METHODS AND MATERIALS: Enamel blocks were exposed to Opalescence PF 10% Carbamide Peroxide (n = 10), Opalescence PF 20% Carbamide Peroxide (n = 10), Opalescence Trèswhite Supreme 10% Hydrogen Peroxide (n = 10) and Opalescence Quick PF 45% Carbamide Peroxide (n = 10) according to the manufacturer's instructions. The control group was enamel blocks (n = 10) kept in artificial saliva. The values were obtained before exposure and after the 14-days treatment period. Enamel blocks were kept in saliva between treatments. Indent marks on enamel blocks were examined using the scanning electron microscope for treatment effects. RESULTS: All four different Opalescence products damaged enamel. The most damage was done when treated for a long period (112 hours). SEM images also showed damage to enamel by all 4 products. Opalescence with 10% and with 20% Carbamide Peroxide showed the highest damage, which also differed significantly (p < 0.05) from the saliva control group (p < 0.05; Tukey-Kramer Multiple comparison test). CONCLUSION: All 4 Opalescence products damaged enamel. Higher damage was done by the 10% carbamide peroxide and 20% carbamide peroxide products because of the much longer exposure period (112 hours in comparison to 7 hours).     

Indikationen zur primären operativen Therapie von Gefäßanomalien im Säuglingsalter

Laser therapy. Since the introduction of laser therapy for treatment of hemangiomas and vascular malformations, primary surgical therapy has gradually lost importance. Particularly hemangiomas, but also venous malformations and lymphangiomas, are nowadays primarily treated by different types of lasers. Especially the Nd:YAG laser with a percutaneous or transcutaneous application technique often leads to satisfying results. Surgical therapy. Surgical therapy is mostly used secondarily in late childhood or in adults after several laser applications for excision of residual scars or other corrective procedures. Despite these improvements in laser therapy, there is still an indication for primary surgical treatment in subcutaneous vascular malformations and in rapidly growing hemangiomas after unsuccessful laser therapy. Even in large vascular anomalies, safe excision with only a little blood loss is possible if the tumors are encapsulated. Case reports. In this paper we want to point out the necessity of primary surgery in three children in whom complications such as loss of sight, facial nerve palsy, and a lethal outcome due to massive hemorrhage in a cystic lymphangioma could be avoided.