Hemoglobin-to-platelet ratio in predicting the incidence of trismus after concurrent chemoradiotherapy.

OBJECTIVE: The significance of pre-hemoglobin-to-platelet ratio (HPR) in predicting the occurrence of radiation-induced trismus (RIT) in locally advanced nasopharyngeal carcinoma patients (LA-NPC) who received concurrent chemoradiotherapy (C-CRT). METHODS: The records of LA-NPC patients with oral examination before and after C-CRT were analyzed. Maximum mouth openings (MMO) were measured before and after C-CRT to confirm RIT status, with an MMO of ≤35 mm defined as RIT. HPR values were calculated on the first day of C-CRT. The relationship between the HPR values and RIT status was discovered using the receiver operating characteristic curve analysis. RESULTS: A total of 43 patients RIT cases among 198 individuals were diagnosed. The optimal HPR cutoff that stratified the patients into two groups was 0.54. RIT incidence was found to be significantly higher in the HPR ≤0.54 group than its HPR >0.54 counterpart(p < 0.001). Univariately T3-4 stage, mean masticator apparatus dose>57.2Gy, and pre-C-CRT MMO ≤40.7 mm were found as the other significant correlates of increased RIT rates(p < 0.05). All four variables seemed to be independently connected to greater RIT incidence in multivariate analysis (p < 0.05, for each). CONCLUSION: The risk of post-C-CRT RIT may be significantly increased when pre-treatment HPR levels are low.

Effect of Induced Membrane on Guided Bone Regeneration in an Experimental Calvarial Model.

OBJECTIVE: The aim of this study was to evaluate the effect of induced membrane on guided bone regeneration and to compare its effect with poly-tetra-flourur-ethylene (PTFE) membrane and collagen membrane. METHODS: Sixteen white Vienna rabbits were used for experiments. Initially 1 defect was created on the parietal bone of all animals and cement was placed inside the defects. After 8 weeks, the bone cements were removed, without damaging the induced membrane formed in the defect cavity. And then 2 more defects were created. All defects were filled with xsenogenic graft materials and were covered with newly formed induced membrane, d-PTFE membrane and collagen membrane. Eight animals were sacrificed at 4th week and other 8 animals were sacrificed at 8th week and all bone specimens were histologically evaluated. RESULTS: New bone formation and bone marrow ratios were significantly higher in induced membrane and d-PTFE membrane group compared to collagen membrane group (P < 0.05) at 4th week. Mature bone ratios were significantly higher in induced membrane and d-PTFE membrane group compared to collagen membrane group (P < 0.05) at 8th week. The best CD31 value was detected with d-PTFE membrane group at 4th week and with induced membrane at 8th week. CONCLUSION: Induced membrane can act as a strong barrier membrane and stimulate bone regeneration. Induced membrane technique can be accepted as a good alternative for the reconstruction of critical size defects in maxillofacial region.

Validity of conventional surgical treatment methods for mandibular dentigerous cysts. Two case reports.

Dentigerous cysts, which are the most commonly seen odontogenic cysts in the jaws, usually expand asymptomatically and extensively. They are surgically eliminated along with the accompanying impacted tooth, because of their destructive nature to the surrounding vital structures, tissues, bone and teeth. The surgical treatment for removing dentigerous cysts includes decompression, marsupialization, enucleation or curettage of the cyst through an extraoral or intraoral approach. Cysts causing tooth displacement and involving loss of bone are treated by marsupialization or decompression, followed by enucleation. In the cases presented here, both patients had enlarged dentigerous cysts in the left mandibular molar region, with an accompanying impacted tooth. Both cases were treated surgically by the enucleation technique alone, without any need for additional autogenous grafts or alloplastic materials to regain integrity of bone structure. They were rehabilitated with dental implants. The implant-retained fixed prostheses functioned well throughout the 24-month evaluation time; and the functional and psychological needs of the patients were provided successfully.

Early implant survival in posterior maxilla with or without beta-tricalcium phosphate sinus floor graft.

PURPOSE: The sinus lift procedure provides a way to increase the amount of available bone and the placement of longer implants. The aim of this study was to evaluate and compare the survival rates of implants inserted in the posterior maxilla (without sinus lift) to simultaneous implant insertion with sinus lift. PATIENTS AND METHODS: Seventy maxillary sinuses in 62 patients were augmented by beta-tricalcium phosphate and 121 implants were inserted into these augmented sinuses (study group) and 136 implants were inserted in the posterior maxilla in 65 patients (control group). Follow-up times were 29.8 and 32.3 months for the study and control groups, respectively. RESULTS: One implant in the study group and 1 implant in the control group failed. All other implants in both groups were functioning well without any significant clinical finding. Implant survivals were 99.17% in the study group and 99.26% in the control group. CONCLUSION: Simultaneous implant insertion and sinus lift with beta-tricalcium phosphate is a safe surgical procedure, and survival rates of implants inserted in the augmented sinus were similar to those of implants inserted in the posterior maxilla without sinus lift.

Effects of titanium plate fixation on mandibular growth in a rabbit model.

PURPOSE: The purpose of this study was to evaluate the effect of metallic rigid fixation of mandibular corpus fracture on mandibular growth in growing rabbits. MATERIALS AND METHODS: Thirteen 90-day-old white New Zealand rabbits weighing 2 to 2.6 kg were included in this study. Unilateral mandibular fractures were created in all of the animals and fixed with microplates and screws. Microplates that had been adapted for fixation of the left (experimental) side were also used as a template for the drilling procedure on the right (control) side of the mandible. The plate was then removed, and screws were inserted. Digital submentovertex radiographs of each animal were taken before the operation and 6 months after surgery. Cephalometric values were analyzed. The distance between the centers of the 2 screws on the right side of the mandible was measured with a caliper in all samples, and values were compared with measurements taken from the left (experimental) side of the mandible upon which the plates had been placed. RESULTS: The mean amount of mandibular growth was 4.38+/-2.43 mm on the right (control) side and 4.64+/-2.27 mm on the left (experimental) side. This difference was not statistically significant (P> .05). The distance between the 2 screws was 13.89+/-0.23 mm on the experimental side and 13.44+/-0.46 mm on the control side. This difference was statistically significant (P< .05). CONCLUSIONS: Metallic fixation of a mandibular body fracture did not cause mandibular asymmetry or restricted mandibular growth in growing rabbits in this relatively small sample.

Comparison of fixation stability of resorbable versus titanium plate and screws in mandibular angle fractures.

PURPOSE: The aim of this study was to compare the fixation reliability and stability of titanium and resorbable plates and screws by simulating chewing forces. MATERIALS AND METHODS: Mandibular angle fractures in 11 sheep hemimandibles were fixed with 4-hole straight titanium plates and 2.0 x 7-mm titanium screws; in addition, 11 hemimandibles were fixed with 4-hole straight resorbable plates and 2.5 x 6-mm resorbable screws according to the Champy technique. The hemimandibles were mounted with a fixation device in a servohydraulic testing unit for compressive testing. Displacement values under 20, 60, 100, 120, 150, and 200 N; maximum displacements; and maximum forces that the model could resist before breakage were recorded and compared. RESULTS: Significant differences were found between resorbable and titanium plates and screws at all forces (20, 60, 100, 120, 150, and 200 N) (P < .05). We found no statistically significant differences in the breaking force and maximum displacement values (displacement values at the breaking forces) between the groups. CONCLUSIONS: The stability of mandibular angle fractures with titanium miniplates under simulated chewing forces was significantly higher than with the resorbable system. Metallic and resorbable fixation systems cannot be used interchangeably to treat mandibular angle fractures under similar loading conditions.

Radiological and Histological Evaluation of the Effects of Cortical Perforations on Bone Healing in Mandibular Onlay Graft Procedures.

BACKGROUND: Perforations of the cortical bone may be an advantage for the success of the autogenous bone graft procedure, but whether this perforation has a positive effect on the bone remains controversial. PURPOSE: This study evaluates the effects of cortical perforation of the autogenous bone block graft radiologically and histologically. MATERIALS AND METHODS: Seven adult pigs were used for this study. On the experimental side, cortical perforation at the host site was prepared, while no perforation was done on the control side. The specimens were evaluated, and the Wilcoxon signed-rank test was used for statistical analysis. RESULTS: In the radiological evaluation, the Wilcoxon signed-rank test indicated no significant differences in densities among the grafts (p = .23) with a mean of 4.29 ± 0.951 for the unperforated graft side and 3.57 ± 0.976 for the decorticated graft side. In histological evaluation, there was a significant difference in the thickness of the grafts between the groups (experimental group 3.71 ± 1.286, control group: 4.71 ± 0.488; p = .033). However, when the remodeling and osteoblastic activity in the grafts were measured, no significant differences were observed between the groups (p = 1 and p = .133, respectively). CONCLUSION: In augmentation with mandibular onlay bone grafts, cortical perforations in the recipient site make no distinct contribution to bone healing within 12 weeks.

Is permanent maxillary tooth removal without palatal injection possible?

OBJECTIVE: The aim of the present study was to demonstrate if articaine HCl could provide palatal anesthesia in maxillary tooth removal without the need for a second palatal injection. STUDY DESIGN: Of 53 patients, 23 had bilateral and 30 had unilateral extractions. In the study group 2 mL of 4% articaine/HCl with 1:100,000 epinephrine was injected into the buccal vestibule of the tooth. After 5 min the extraction was performed. 27 subjects were controls and subjected to the same protocol with palatal injection. All patients completed a Faces Pain Scale (FPS) and a 100-mm Visual Analogue Scale (VAS) after extraction. RESULTS: According to VAS and FPS scores, when permanent maxillary tooth removal with palatal injection (97.5%) and without palatal injection (96.8%) were compared the difference was not statistically significant (P > .05) [corrected]. CONCLUSION: Permanent removal of maxillary teeth without palatal injection is possible by depositing 2 mL articaine/HCl to the buccal vestibule of the tooth.