Squamous cell cancer of the buccal mucosa in young adults

BACKGROUND: Squamous cell carcinoma of the buccal mucosa is predominantly a cancer of elderly people and is seen rarely in young adults. Although many aetiological factors have been postulated, tobacco alone has been implicated as the main factor in the aetiology of such cancers at any age. PATIENTS AND METHODS: A retrospective analysis of 46 patients with cancer of the buccal mucosa who were under the age of 35 years at the time of presentation was made to evaluate their survival and predictors of survival. The details were extracted from the computerised records and case records of the Regional Cancer Centre, Trivandrum, India. These were analysed with particular emphasis on risk factors, clinical extent, and treatment. Survival was analysed by the Kaplan-Meier method, and differences in survival were compared using the log-rank test. RESULTS: The male:female ratio was 6.7:1. Almost all the patients (n = 42, 91%) used either tobacco or alcohol, with tobacco chewing being the most common. The 3 and 5 years disease-free survival were 72 and 61%, respectively. Non-smokers and patients with an advanced T stage at presentation had significantly worse prognoses.     

Effects of bilateral upper first premolar extraction on the mandible

The purpose of this study was to evaluate the effects of bilateral upper premolar extraction on mandibular growth. Twenty-six subjects (eight males, 18 females) in maximum pubertal growth with an Angle Class II molar relationship, normal to mild overjet increase, mild or no lower arch length discrepancy but severe upper arch discrepancy and no severe skeletal discrepancy were divided into two groups equal in number and gender, as extraction and control groups. The median chronological age was 11.2 years in the extraction group and 12.6 years in the controls. The subjects were observed for a median period of 1.1 years in the extraction group after bilateral extraction of the upper premolars and 1.2 years in the controls until termination of pubertal growth (DP3u) without any orthodontic treatment. Twenty-nine linear and angular measurements were made on 52 lateral cephalograms and hand-wrist radiographs taken before and after the study period. The increase in SNB measured on the total superimposition was significantly greater in the controls than in the extraction group (P < 0.05). In addition, anterior mandibular (counter-clockwise) rotation was only significant (P < 0.05) in the control group. Thus, it might be suggested that bilateral upper premolar extractions might affect the mandibular rotation tendency.     

Use of bar-clip attachments to enhance the retention of a maxillofacial prosthetic obturator: a clinical report

Precision attachments are commonly used in prosthetic dentistry but are still questioned in maxillofacial prosthetics. The aesthetic enhancement and functional rigidity provided by attachments are favourable features to many challenging clinical situations such as class-III defect (Aramany's maxillectomy classification). Surgical reconstruction is the standard treatment for this type of defect repair. However, owing to the need for dental rehabilitation and patient reserve, prosthetic rehabilitation was the modality chosen in this clinical case. The use of bar attachments is described in this paper as providing increased stability and retention of the prosthesis, and improved obturator water and airtightness.     

Plaque removing capacity of a novel high pressure water irrigator

PURPOSE: To evaluate the capacity of a novel oral water irrigator to remove established plaque deposits. METHODS: The study was designed as a randomized two-treatment, crossover, examiner-blinded clinical trial. The plaque removing capability of a prototype oral irrigator was compared to a conventional electric toothbrush. After 48 hours of plaque accumulation the 35 subjects were randomly assigned to professional plaque removal by either oral irrigation or by electric toothbrushing for a timed 2-minute total cleaning. Pre- and post cleaning plaque was disclosed and gingival abrasions were identified. Plaque was assessed on gingival and approximal surfaces of the oral and buccal sites according to the Rustogi et al modification of the Modified Navy Plaque Index. The assessment of gingival abrasions was performed according to the method introduced by Danser et al. RESULTS: The overall plaque removing capacity of the oral irrigator reached approximately 40.7 +/- 16.7% as compared to 71.6 +/- 11.5% by the electric toothbrush. Similar effects were observed for the gingival and approximal areas. The electric toothbrush caused significantly more gingival abrasions than the oral irrigator.     

In vitro analysis of 'smear layer' on human dentine using ac-impedance spectroscopy

OBJECTIVE: To analyse smear layers on human dentine using ac-impedance spectroscopy. METHODS: Dentine samples were prepared from extracted, sound, third molars. Impedance measurements were carried out on dentine samples before and after etching. After measuring, samples were examined under scanning electron microscope (SEM) to correlate electrical measurements with structure. RESULTS: Marked differences in impedance before and after etching were demonstrated. SEM investigation showed that a smear layer overlies dentine surfaces before etching, but completely disappeared after etching, leaving open dentinal tubules. CONCLUSIONS: The clinical removal of smear layers is still subjective. This objective method, based on combined ac-impedance and admittance measurement in vitro, has the potential to allow development of standardised techniques and if developed further may be of use in vivo.     

A randomized clinical trial comparing enamel matrix derivative and membrane treatment of buccal Class II furcation involvement in mandibular molars. Part I: Study design and results for primary outcomes

BACKGROUND: The objective of this multicenter, randomized trial was to compare enamel matrix derivative (EMD; test) with barrier membranes (control) for the treatment of mandibular buccal Class II furcation defects. METHODS: Forty-five patients with 90 comparable defects on contralateral molars were included. Defects were randomly assigned to EMD or bioabsorbable barrier membrane; the contralateral defect received the alternative treatment. Assessments at baseline and 8 and 14 months included gingival margin levels, probing depths, bleeding on probing, vertical attachment levels, and vertical bone sounding from a stent at five buccal sites/ tooth. Defect dimensions were recorded at surgery and during reentry at 14 months. Change of open horizontal furcation depth was the primary outcome variable. Adverse reactions and patient perceptions were also noted. RESULTS: Both treatment modalities led to significant clinical improvements. The median reduction of open horizontal furcation depth was 2.8 mm with the corresponding interquartile interval (1.5 mm, 3.5 mm) at test sites compared with 1.8 mm (1.0 mm, 2.8 mm) at control sites. The Hodges-Lehmann estimator of the advantage (reduction test versus control) was 0.75 mm (95% confidence interval [CI]: 0.125 mm, 1.375 mm, P = 0.033, Wilcoxon). The frequency of complete furcation closure was 8/45 (test) and 3/45 (control); partial closure, 27/45 in both groups; no change, 9/45 and 11/45, respectively; and deterioration, 1/45 and 4/45, respectively. The frequency of no pain or no swelling at 1 week post-surgery was 62% and 44%, respectively, at the test sites and 12% and 6% at the control sites. CONCLUSION: There was a significantly greater reduction in horizontal furcation depth and a comparatively lower incidence of postoperative pain/swelling following enamel matrix derivative compared to membrane therapy.     

Sinus floor augmentation with simultaneous placement of dental implants in the presence of platelet-rich plasma or recombinant human bone morphogenetic protein-7

The aim of the present study was to evaluate the possible benefit of platelet-rich plasma (PRP) in sinus grafting as compared with recombinant human bone morphogenetic protein-7 (rhBMP-7). For this purpose, we performed a bilateral sinus augmentation with anorganic bovine bone and simultaneous insertion of a titanium screw implant in five miniature pigs. Six hundred microliters of PRP and 15%-vol. autologous bone, which was collected with a trap during preparation of the implant recipient site, were added to the right sinus and 420 microl rhBMP-7 to the left sinus. A polychrome sequential labeling was performed. The animals were sacrificed 6 weeks after surgery. Undecalcified ground sections were evaluated by microradiography, digitized histomorphometry and under fluorescent light. The mean bone-implant contact using rhBMP-7 was 45.8% and 5.7% under PRP (P=0.002). The mean height of newly mineralized bone in the augmented area using rhBMP-7 amounted to 8.3 mm as opposed to 3.6 mm under PRP (P=0.013). Using PRP, the mean area of the newly formed bone was enhanced (51.3%) as compared with rhBMP-7 (33.1%); however, this difference was not statistically significant (P=0.081). In conclusion, under the selected experimental conditions the use of rhBMP-7 led to superior outcomes with regard to the osseointegration of dental implants and the height of new bone as compared with the use of PRP.     

Finite element analysis of effect of prosthesis height, angle of force application, and implant offset on supporting bone

PURPOSE: This finite element analysis was conducted to determine the magnitude of stress in the supporting bone when implants were arranged in either a straight-line or an offset configuration. In addition, the effects of axial and nonaxial loading and changes in prosthesis height were assessed. MATERIALS AND METHODS: An 8-node hexahedral solid-element 3-dimensional finite element analysis model of the mandible was created using PATRAN software. Three titanium endosseous implants were placed in the model 7 mm apart. The center implant was placed on the line from the centers of the terminal implants (no offset), 1.5 mm lateral to this line (1.5-mm offset), or 3.0 mm lateral to this line (3.0-mm offset). Forces of 200 N were applied to a point corresponding to the center of the middle implant when the implants were in a straight-line configuration. Forces were applied in a straight vertical direction or in 15-degree increments to the vertical to a maximum of 60 degrees. Simulated type IV gold prostheses were made to simulate heights of 6 and 12 mm. RESULTS: The least stress in the supporting bone was found with vertical loading of the no-offset implants with the 6-mm prosthesis (3.12 MPa) followed by the same alignment with the 12-mm prosthesis (3.86 MPa). Changing the angle of force application by 15 degrees resulted in increased stress to the underlying bone, and the creation of an offset did not fully compensate for this increased stress. DISCUSSION: In contrast to previous studies, this study examined 3 elements not previously studied together in a single finite element analysis, using the maximum offset defined by normal anatomic contours of mandibular premolar and molar teeth, thereby describing the relative importance of clinically relevant methods for stress reduction. CONCLUSIONS: Vertical loading of an implant-supported prosthesis produced the lowest stress to the supporting bone. Changes in the angle of force application resulted in greater stress to supporting bone. Reduction in prosthesis height or use of an offset implant location for the middle implant reduced stress, but the reduction did not compensate for the increase found with off-axis loading.     

Evaluation of radiographic predictors to assess the rate of mandibular residual ridge resorption.

Sixty healthy clinical edentulous patients (thirty male and thirty female) were chosen for the study. Panoramic and lateral cephalometric radiographs were taken of each patient. The amount of bone loss was estimated from the panoramic radiographs as per the formula proposed by Wical and Scoop. The rate of mandibular residual resorbed ridge (RRR) expressed as percentage of bone loss per year was then computed. The correlation between the mandibular RRR and gonial cortical thickness and the percentage of cortical bone at the symphysis was tested. These parameters were also compared between the male and female patients. The rate of mandibular RRR, expressed as percentage of bone loss per year, was found to be indirectly correlated with the cortical thickness at gonion as measured from the panaromic and the lateral cephalometric radiographs. The values of students 't' test for mean differences between the female and the male patients with respect to the rate of mandibular RRR and the cortical thickness at the gonion were found to be statistically significant.