Influence of tooth clench on the soleus H-reflex

The Hoffmann (H) reflex is elicited by electrical stimulation of a mixed nerve and is used to measure the excitability of the spindle-motoneuron synapse. Recent investigations have indicated a positive correlation between increases in bite force and H-reflex facilitation. However, these investigations did not examine the H-reflex in detail or the possible role of periodontal mechanoreceptors (PMRs) in this facilitation. The current investigation was performed to determine whether PMRs play a role in H-reflex facilitation during tooth clench (TC). The H-reflex was elicited in the soleus muscle of human subjects while bite level was maintained at rest (0 N), 40 N, 80 N and maximal TC. The front teeth that contributed to the (40 N and 80 N) bite force were then locally anaesthetised (LA), and the protocol was repeated. The current data suggest that the effect of TC on the H-reflex amplitude in the human limb muscles is variable from one subject to the next. Statistical analysis has shown that the H-reflex was significantly smaller during the rest condition than during the 80 N bite (p<0.05) in both non-LA and LA conditions. Since LA did not alter the response, our results do not support that the PMRs play a major role in the facilitation of distal muscle activity.     

Impaired healing response of periodontal furcation defects following flap debridement surgery in smokers. A controlled clinical trial

OBJECTIVES: The purpose of the present parallel-design, controlled clinical trial was to evaluate the treatment outcome of periodontal furcation defects following flap debridement surgery (FDS) procedure in cigarette smokers compared to non-smokers. MATERIALS AND METHODS: After initial therapy, 31 systemically healthy subjects with moderate to advanced periodontitis, who presented at least one Class I or II molar furcation defect, were selected. Nineteen patients (mean age: 40.3 years, 15 males) were smokers (>or=10 cigarettes/day) and 12 patients (mean age: 44.8 years, 3 males) were non-smokers. Full-mouth plaque score (FMPS) and full-mouth bleeding score (FMBS), probing pocket depth (PPD), vertical clinical attachment level (v-CAL), and horizontal clinical attachment level (h-CAL) were assessed immediately before and 6 months following surgery. RESULTS: Overall, statistically significant v-CAL gain was observed in smokers (1.0 +/- 1.3 mm) and non-smokers (1.3+/-1.1 mm), the difference between groups being statistically significant (p=0.0003). In proximal furcation defects, v-CAL gain amounted to 2.3+/-0.7 mm in non-smokers as compared to 1.0+/-1.1 mm in smokers (p=0.0013). At 6 months postsurgery, non-smokers presented a greater h-CAL gain (1.3+/-1.1 mm) than smokers (0.6+/-1.0 mm), with a statistically significant difference between groups (p=0.0089). This trend was confirmed in both facial/lingual (1.4+/-1.0 versus 0.8+/-0.8 mm) and proximal furcation defects (1.2+/-1.3 versus 0.5+/-1.2 mm). The proportion of Class II furcations showing improvement to postsurgery Class I was 27.6% in smokers and 38.5% in non-smokers. After 6 months, 3.4% of presurgery Class I furcation defects in smokers showed complete closure, as compared to 27.8% in non-smokers. CONCLUSIONS: The results of the present study indicated that (1) FDS produced clinically and statistically significant PPD reduction, v-CAL gain, and h-CAL gain in Class I/II molar furcation defects, and (2) cigarette smokers exhibited a less favorable healing outcome following surgery in terms of both v-CAL and h-CAL gain.     

Treatment of pseudo Class III malocclusion by modified Hawleys appliance with inverted labial bow

Pseudo Class III malocclusion is characterized by an anterior crossbite with functional forward mandibular displacement. Various appliances have been devised for early treatment of a pseudo Class III. The aim of this article is to highlight the method of construction and use a simple removable appliance termed as "Modified Hawleys appliance with inverted labial bow" to treat psuedo class III malocclusion in the mixed dentition period. It also emphasizes the importance of differentiating between true Class III and pseudo Class III. This appliance in this type of malocclusion enabled the correction of a dental malocclusion in a few months and therapeutic stability of a mesially positioned mandible encouraging favorable skeletal growth.     

Platelet-derived growth factor stimulates bone fill and rate of attachment level gain: results of a large multicenter randomized controlled trial

BACKGROUND: Growth factors are generally accepted to be essential mediators of tissue repair via well-established mechanisms of action that include stimulatory effects on angiogenesis and cellular proliferation, ingrowth, differentiation, and matrix biosynthesis. The aim of this study was to evaluate in a large-scale, prospective, blinded, and randomized controlled clinical trial the safety and effectiveness of purified recombinant human platelet-derived growth factor (rhPDGF-BB) mixed with a synthetic beta-tricalcium phosphate (beta-TCP) matrix for the treatment of advanced periodontal osseous defects at 6 months of healing. METHODS: Eleven clinical centers enrolled 180 subjects, each requiring surgical treatment of a 4 mm or greater intrabony periodontal defect and meeting all inclusion and exclusion criteria. Subjects were randomized into one of three treatment groups: 1) beta-TCP + 0.3 mg/ml rhPDGF-BB in buffer; 2) beta-TCP + 1.0 mg/ml rhPDGF-BB in buffer; and 3) beta-TCP + buffer (active control). Safety data were assessed by the frequency and severity of adverse events. Effectiveness measurements included clinical attachment levels (CAL) and gingival recession (GR) measured clinically and linear bone growth (LBG) and percent bone fill (% BF) as assessed radiographically by an independent centralized radiology review center. The area under the curve (AUC), an assessment of the rate of healing, was also calculated for CAL measurements. The surgeons, clinical and radiographic evaluators, patients, and study sponsor were all masked with respect to treatment groups. RESULTS: CAL gain was significantly greater at 3 months for group 1 (rhPDGF 0.3 mg/ml) compared to group 3 (beta-TCP + buffer) (3.8 versus 3.3 mm; P = 0.032), although by 6 months, this finding was not statistically significant (P = 0.11). This early acceleration of CAL gain led to group 1 exhibiting a significantly greater rate of CAL gain between baseline and 6 months than group 3 as assessed by the AUC (68.4- versus 60.1-mm weeks; P = 0.033). rhPDGF (0.3 mg/ml)-treated sites also had significantly greater linear bone gain (2.6 versus 0.9 mm, respectively; P < 0.001) and percent defect fill (57% versus 18%, respectively; P < 0.001) than the sites receiving the bone substitute with buffer at 6 months. There was less GR at 3 months in group 1 compared to group 3 (P = 0.04); at 6 months, GR for group 1 remained unchanged, whereas there was a slight gain in gingival height for group 3 resulting in comparable GR. There were no serious adverse events attributable to any of the treatments. CONCLUSIONS: To our knowledge, this study is the largest prospective, randomized, triple-blinded, and controlled pivotal clinical trial reported to date assessing a putative periodontal regenerative and wound healing therapy. The study demonstrated that the use of rhPDGF-BB was safe and effective in the treatment of periodontal osseous defects. Treatment with rhPDGF-BB stimulated a significant increase in the rate of CAL gain, reduced gingival recession at 3 months post-surgery, and improved bone fill as compared to a beta-TCP bone substitute at 6 months.     

Safety of zygomatic bone harvesting: a prospective study of 32 consecutive patients with simultaneous zygomatic bone grafting and 1-stage implant placement

PURPOSE: The purpose of this prospective study was to evaluate the safety of zygomatic bone harvesting and to determine whether a particulated zygomatic bone graft can be used simultaneously with 1-stage dental implants to reconstruct resorbed edentulous alveolar ridges. MATERIALS AND METHODS: Altogether, 82 dental implants were placed in 32 patients. Particulated bone grafts harvested from the zygomatic process were used in 72 of the implant sites. The volume of bone harvested, intraoperative complications, morbidity, and complications on follow-up visits were recorded. Implant survival was examined prospectively. RESULTS: As a harvest site, the zygoma yielded enough bone to complete the reconstructions in each case. The average zygomatic bone graft volume was 0.90 mL (SD 0.30). Perforation of the maxillary sinus occurred at 11 zygomatic sites. None of these perforations led to postoperative problems. No paresthesias or other complications were noted during follow-up examinations. Mean duration of postoperative swelling was 4.5 days, and patients used pain medication for a mean duration of 4 days. After the mean follow-up period of 26.9 months postplacement, 80 of 82 implants were osseointegrated (survival rate 97.6%). DISCUSSSION: Zygomatic bone is an alternative donor site for bone harvesting with low morbidity. The bone graft yielded is sufficient for use in 2 to 3 implant sites. CONCLUSIONS: The zygoma was a safe intraoral bone harvesting donor site in this patient population. Further, the use of simultaneous particulated zygomatic bone grafts and 1-stage implant placement appears to be an effective procedure.     

Sonicated extract of Enterococcus faecalis induces irreversible cell cycle arrest in phytohemagglutinin-activated human lymphocytes

The purpose of this study was to examine whether the sonicated extract of Enterococcus faecalis (SEF) alters the cell cycle transition of lymphocytes and thus regulates the fate of the arrested cells. Human lymphocytes were activated by phytohemagglutinin in the presence or absence of SEF, and cell cycle was assessed by flow cytometry. Seventy-two hours after activation with phytohemagglutinin, cells were activated from G0/G1 to S (6.1%) and G2/M (3.8%) phases of the cell cycle. In contrast, pretreatment with SEF resulted in 90.5% of cells remaining in G0/G1, and cell cycle progression to the S and G2/M phases was consequently inhibited. Caspase assay demonstrated that SEF-treated cells exhibited significantly increased apoptosis (56.7%) compared with phytohemagglutinin alone (28.1%). We propose that if this irreversible cell cycle arrest induced by E. faecalis occurs in vivo, it may result in local immunosuppression and contribute to the pathogenesis of endodontic failure. Our findings that E. faecalis can inhibit lymphocyte responses may be of particular relevance to the pathogenesis of endodontic failure. Although the immunologic mechanism involved in the pathogenesis of persistent periapical lesion is not clearly defined, it is reasonable to predict that the altered immune reaction may be linked to the immunosuppressive potential of E. faecalis or other oral bacteria.     

A new technique of impression making for an obturator in cleft lip and palate patient

Cleft lip and palate is a birth defect occurring in the orofacial region. One of the immediate problems to be addressed in a newborn with this defect would be to aid in suckling and swallowing. Here we present a case of a 5-day-old infant with unilateral cleft lip and palate for whom feeding obturator was made by using a simplified impression technique to facilitate feeding.     

Multi-unit fixed partial denture for a bilateral cleft palate patient: a clinical report

Patients with cleft palates eventually require definitive fixed or removable dental prostheses after the maintenance of arch alignment and occlusal relationship during adolescence. This case report presents application of a resin composite veneered fixed partial denture utilized as a definitive prosthesis for a bilateral cleft palate patient after stable occlusion had been established orthodontically. The composite veneered long span fixed partial denture provides adequate aesthetics and function.     

Unexpected cerebrospinal fluid rhinorrhea after a spinal anesthesia

A 47-year-old woman presented with a left-sided watery nasal discharge persisting for 3 weeks after an orthopedic operation using spinal anesthesia. The testing of the nasal fluid for β-2 transferrin confirmed that the leakage was cerebrospinal fluid (CSF). The computed tomographic cisternography revealed a left-sided bone defect in the cribriform plate. Endonasal approach was performed for closing the defect. At 3-month follow-up, CSF rhinorrhea had not recurred. In this report, we present an unexpected CSF rhinorrhea after a spinal anesthesia and discuss the reason of spontaneous leak after spinal anesthesia, as well as discuss current diagnosis and management of CSF rhinorrhea with the composite graft.     

The effect of safflower seed extract on periodontal healing of 1-wall intrabony defects in beagle dogs

BACKGROUND: Recent interest in naturally based products has increased. Various herbal extracts are known to have a variety of medicinal properties. Among the various natural medicines, safflower seeds have beneficial effects on various bone diseases such as bone fracture, osteoporosis, and osteodysplasia. In addition, they are known to have anti-inflammatory effects. The objective of this study was to evaluate the effect of a safflower seed extract (SSE) on the regeneration of periodontal tissue in a preclinical 1-wall model in dogs. METHODS: Preclinical 1-wall periodontal defects were surgically created in the mesial aspect of the maxillary third and mandibular fourth premolar and in the distal aspect of the maxillary first and mandibular second premolar, and were randomly assigned to receive SSE/collagen (SSE/Col), phosphate-buffered saline/collagen (buffer control), or root planing only (surgical control). The created 1-wall defect configuration was 4 mm in depth by 4 mm in width. We selected the segment showing the best activity to the osteoblast cells that was sensitive to the formation of calcified nodules among the SSE fractions extracted from various organic solvents. The animals were euthanized at 8 weeks postsurgery, and block sections of the defects were collected for histologic and histometric analysis. RESULTS: The junctional epithelium migration did not show any statistically significant differences among the treatments. In connective tissue adhesion, the SSE/Col group and the buffer control group showed significant differences compared to the surgical control group. New cementum averaged 3.84 +/- 0.57 mm, 3.75 +/- 0.24 mm, and 1.53 +/- 1.22 mm for the SSE/Col group, the buffer control group, and the surgical control group, respectively, with the SSE/Col and buffer control groups significantly different from the surgical control group (P < 0.05). The amount of intrabony cementum in the SSE/Col group was significantly different (P < 0.01) from the surgical control group, but the amount of suprabony cementum did not demonstrate any statistical difference between the different treatments. The amount of new alveolar bone averaged 2.93 +/- 0.70 mm, 2.10 +/- 0.63 mm, and 1.20 +/- 0.65 mm for the SSE/Col group, the buffer control group, and the surgical control group, respectively. The difference in alveolar bone regeneration between the SSE/Col group and the surgical control group was significantly different (P < 0.01). Root resorption was often observed, but no ankylosis was present. CONCLUSION: Wound conditioning with safflower seed extracts may contribute to bone formation but appears to have unpredictable potential for stimulating periodontal regeneration including new cementum.