Maria B. Papageorge

Effects of Mandibular Retropositioning, With or Without Maxillary Advancement, on the Oro-Naso-Pharyngeal Airway and Development of Sleep-Related Breathing Disorders

PURPOSE Literature suggests that patients without pre-existing sleep-related breathing disorders who undergo orthognathic surgery for treatment of facial asymmetry may experience changes in their oropharyngeal airway. Mandibular retropositioning can compromise the posterior airway space, alter the physiologic airflow through the upper airway, and predispose patients to development of obstructive sleep apnea syndrome (OSAS). PATIENTS AND METHODS This study was a retrospective cohort analysis of 26 patients who underwent mandibular retropositioning with or without maxillary advancement within the past 5 years at Tufts University School of Dental Medicine. Pre- and postoperative lateral cephalometric radiographs were analyzed with digital DOLPHIN software (Dolphin Imaging, Chatsworth, CA) for evidence of changes to the posterior airway dimension. In addition, patients were evaluated postoperatively with SNAP polysomnography (model 4/6; SNAP Laboratories, Wheeling, IL) for evidence of OSAS. RESULTS Results indicated that mandibular retropositioning greater than or equal to 5 mm decreased the posterior airway space below 11 mm (30.75%, P = .03) and showed evidence of soft palate elongation greater than 32 mm (15.39%, P = .037) in a significant number of patients. However, as determined by cephalometric analysis, mandibular retropositioning greater than or equal to 5 mm in combination with maxillary advancement had no significant effect on the posterior airway space or soft palate. CONCLUSION Postoperative SNAP polysomnography showed higher incidence of mild to moderate OSAS in patients who underwent mandibular retropositioning greater than or equal to 5 mm (69.25%) compared with patients who underwent mandibular retropositioning in combination with maxillary advancement (38.46%, P = .039).

A comparative study of magnetic resonance imaging versus computed tomography for the evaluation of maxillary and mandibular tumors

The relative value of magnetic resonance imaging (MRI) versus computed tomography (CT) for imaging benign and malignant lesions of the maxilla and mandible was studied in a group of 16 patients. The imaging methods were evaluated for their ability to detect the lesion and define lesion margins, soft tissue extension, and bone involvement. The abnormality was identifiable with both imaging methods. For benign cystic lesions of either the maxilla or mandible (50%), MRI was overall equal to or better than CT. Magnetic resonance imaging was superior to CT in the evaluation of lesion margins and soft tissue extent of disease, whereas it was equal or slightly inferior to CT in lesion detection and in the evaluation of bone involvement. In the imaging of malignant neoplasms (50%), MRI was overall superior to CT in all four categories reviewed. Magnetic resonance imaging also had the highest rate of correlation with clinical findings, either from physical examination or at the time of surgery.

In Vitro Biomechanical Evaluation of the Use of Conventional and Locking Miniplate/Screw Systems for Sagittal Split Ramus Osteotomy

PURPOSE The aim of this in vitro study was to assess the biomechanical stability of 9 different osteosynthesis methods after sagittal split ramus osteotomy by simulating the masticatory forces and using a 3-point biomechanical test method. MATERIALS AND METHODS Forty-five polyurethane hemimandibles with bone-like consistency were randomly assigned to 9 groups (n = 5) and subjected to sagittal split ramus osteotomy. After 4-mm advancement of the distal segment, the bone segments were fixed by different osteosynthesis methods using 2.0-mm miniplate/screw systems: group A, one 4-hole conventional straight miniplate; group B, one 4-hole locking straight miniplate; group C, one 4-hole conventional miniplate and one bicortical screw; group D, one 4-hole locking miniplate and 1 bicortical screw; group E, one 6-hole conventional straight miniplate; group F, one 6-hole locking straight miniplate; group G: two 4-hole conventional straight miniplates; group H, two 4-hole locking straight miniplates; and group I, 3 bicortical screws in an inverted-L pattern. All models were mounted on a base especially constructed for this purpose. Using a 3-point biomechanical test model, the hemimandibles were loaded in compressive strength in an Instron machine (Norwood, MA) until a 3-mm displacement occurred between segments vertically or horizontally. Data were analyzed by analysis of variance and Tukey test (alpha = 1%). RESULTS The multiparametric comparison of the groups showed a statistically significant difference (P < .01) between groups that used 2 miniplates (groups G and H), 1 miniplate and 1 bicortical screw (groups C and D), and only bicortical screws (group I) compared with groups that used only 1 miniplate with 2 screws per segment (groups A and B) and 3 screws per segment (groups E and F). CONCLUSION The placement of 2.0-mm-diameter bicortical screws in the retromolar region, associated or not with conventional and locking miniplates with monocortical screws, promoted a better stabilization of bone segments. Locking miniplates presented a better performance in bone fixation in all groups.

Cementoblastoma involving multiple deciduous teeth

The first case of a cementoblastoma involving multiple mandibular deciduous incisors is presented. The clinical, radiographic, and histopathologic features of the cementoblastoma are reviewed. The possible etiology for the pain frequently associated with this lesion is discussed.

In vitro evaluation of conventional and locking miniplate/screw systems for the treatment of mandibular angle fractures

This in vitro study evaluated the influence of the type of miniplate and the number of screws installed in the proximal and distal segments on the stability and resistance of Champys osteosynthesis in mandibular angle fractures. Sixty polyurethane hemimandibles with bone-like consistency were randomly assigned to four groups (n=15) and sectioned in the mandibular angle region to simulate fracture. The bone segments were fixed by different osteosynthesis methods using 2.0 mm miniplates and 2.0 mm × 6 mm monocortical screws. In groups 1 and 2, two conventional (G1) or locking (G2) screws were installed in each bone segment using a conventional (G1) or a locking (G2) straight miniplate; in groups 3 and 4, three conventional (G3) or locking (G4) screws were installed in the proximal segment and four conventional (G3) or locking (G4) screws were installed in the distal segment using a conventional (G3) or a locking (G4) seven-hole straight miniplate. The hemimandibles were loaded in compressive strength until a 4mm displacement occurred between the segments, vertically or horizontally. Locking plate/screw systems provided significantly greater resistance to displacement than conventional ones (p<.01). Locking miniplates offered more resistance than conventional miniplates. Long locking miniplates provided greater stability than short ones.

Which kind of miniplate to use in mandibular sagittal split osteotomy? An in vitro study

This study verified the resistance to displacement of six miniplate fixation methods after sagittal split osteotomy (SSO). SSO was performed in 30 polyurethane synthetic mandible replicas. The distal segments were advanced (4 mm) and specimens were grouped according to the fixation method: four-hole standard miniplate; four-hole locking miniplate; six-hole standard miniplate; six-hole locking miniplate; six-hole standard sagittal miniplate; six-hole locking sagittal miniplate. Biomechanical evaluation was performed by applying compression loads to three points on the second molar region, using an Instron universal testing machine until a 3mm displacement of the segments occurred. Compression loads able to produce 3mm displacement were recorded in kN and subjected to analysis of variance (P<0.01) and Tukeys tests for comparison between groups (P<0.05). The locking sagittal miniplate showed higher resistance to displacement than the regular four- and six-hole locking and standard miniplates. No significant differences were observed between the locking sagittal miniplate and the regular sagittal or the four-hole locking miniplates. Two of the three groups with the best results had locking plate fixation methods. Fixation of SSO with a single miniplate is better accomplished using six-hole locking sagittal miniplates, six-hole standard sagittal miniplates, or four-hole locking miniplates; these methods are more resistant to displacement.

Solitary neurofibroma of the mandible and infratemporal fossa in a young child: Report of a case

The first case of a rare and unusual solitary neurofibroma of the mandible that caused bony erosion and extension into the adjacent soft tissues of the infratemporal fossa is presented. The clinical, radiographic, and histopathologic features of the neurofibroma are reviewed. The diagnostic procedures and the surgical treatment of this tumor in a young child are discussed.

The cancer-promoting effect of N-Nitrosonornicotine used in combination with a subcarcinogenic dose of 4-nitroquinoline-N-oxide and 7, 12-dimethylbenz (A) anthracene

PURPOSE This study was conducted to determine the possible carcinogenic role of N-Nitrosonornicotine (NNN) when combined with subcarcinogenic doses of strong carcinogens dimethylbenz (a) anthracene (DMBA) and 4-nitroquinoline-N-oxide (4NQO) in the hamster cheek pouch. MATERIALS AND METHODS Eighty-five Syrian golden hamsters were randomly divided into three main groups. Group A contained 35 animals, 20 of which were treated with 0.1% DMBA followed by 4% NNN (A-I), 5 with 0.1% DMBA (A-II), 5 with 4% NNN (A-III), and 5 with mineral oil alone (A-IV). Group B contained 23 animals, 13 of which were treated with 0.5% 4NQO followed by 4% NNN (B-I), 5 with 0.5% 4NQO (B-II), and 5 animals with propyleneglycol alone (B-III). Group C contained 27 animals, 14 of which were treated with 0.1% DMBA followed by 4% NNN and 0.5% 4NQC (C-I), and 13 with 0.1% DMBA followed by 0.5% 4NQO (C-II). All animals were treated three times per week for 16 weeks. A total of 7 animals died during this period. RESULTS Squamous cell carcinoma (SCCA) developed in eight animals (67%) in the group treated with all three chemicals (C-I), in four animals (33%) treated with DMBA and 4NQO (C-II), in two animals (15%) treated with 4NQO and NNN (B-I), and in two animals (11%) treated with DMBA and NNN (A-I). The difference between the number of animals that developed carcinoma in group C-I and those in groups A-I and B-I was statistically significant (P < .05) and this difference reached a significant value when group C-I and C-II were compared (P < or = .1). There was a direct relationship between the number of tumors produced in animals and the number of different chemicals applied. CONCLUSION The results of this study indicate that NNN, when combined with subcarcinogenic doses of other strong carcinogens, is a promoter in the development of squamous cell carcinoma and that 4NQO in 0.5% concentration is a stronger carcinogen than 0.1% DMBA.

Referral of symptoms from the trigeminal to the facial nerve as a sequel to dental infection

The case reported in this article documents a clinical situation in which an infected tooth resulted in secondary clinical manifestations involving the seventh cranial nerve in addition to the fifth cranial nerve. A theory for the referral mechanism is proposed.

Biomechanical evaluation of different osteosynthesis methods after mandibular sagittal split osteotomy in major advancements

The aim of this study was to assess the biomechanical stability of six different osteosynthesis methods after sagittal split osteotomy. Sixty polyurethane hemimandibles were divided into two groups, with six subgroups in each. After 10-mm advancement of the distal segment (group 1) and 10-mm advancement combined with 20° counterclockwise rotation (group 2), the bone segments were fixed using 2.0-mm plates/screws as follows: subgroup A, one conventional straight plate; subgroup B, two conventional straight plates; subgroup C, one conventional sagittal plate; subgroup D, one locking straight plate; subgroup E, two locking straight plates; subgroup F, one locking sagittal plate. The hemimandibles were tested for compressive strength by three-point biomechanical test, until there was 3mm of displacement between the segments. The fixations showed better performance in group 1 than in group 2 in all cases, with statistical significance for subgroups A, C, and D. In both groups, the use of two straight miniplates showed the most resistance, followed by the sagittal miniplates. However, in counterclockwise rotations, no statistically significant difference was found between two conventional straight plates and the sagittal locking plate. This study shows that the use of two plates is the form of fixation with the minimum displacement. If the clinician opts to use one plate, a sagittal plate is the best alternative.