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school:SOM

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The effect of different implant macrogeometries and surface treatment in early biomechanical fixation: an experimental study in dogs

Coelho, Paulo G; Granato, Rodrigo; Marin, Charles; Teixeira, Hellen S; Suzuki, Marcelo; Valverde, Guilherme B; Janal, Malvin N; Lilin, Tomas; Bonfante, Estevam A
Implant surface characterization and biomechanical testing were made to evaluate the effect of different surface treatments along with different implant bulk configurations expressed as biomechanical fixation at early implantation times. Three implant surfaces, namely bioactive ceramic electrodeposition (ED), alumina-blasted/acid etched (AB/AE), and resorbable blasting media (RBM) were fabricated in three implant macrogeometries (cylindrical, small chamber, and large chamber). All combinations between surface and bulk configurations were placed in the radii of beagle dogs (n=18), which were euthanized 14 and 40 days after surgery (n=9 animals per time in vivo). The implants were subjected to torque to interface fracture. Effects of time, surface, and macrogeometry on torque to interface fracture were evaluated by a GLM at 95% level of significance. The results showed a significant increase in torque as time elapsed in vivo (p<0.001), and that the ED surface presented significantly higher values compared to AB/AE and RBM (p<0.001) at both times. The small chamber only presented a significantly higher biomechanical fixation compared to other geometries at 40 days in vivo (p=0.02). Biomechanical fixation at 14 and 40 days was affected by implant surface treatment, whereas implant design only affected results at 40 days in vivo.
PMID: 22098896
ISSN: 1878-0180
CID: 160238

Effect of implant diameter on reliability and failure modes of molar crowns

Freitas-Junior, Amilcar C; Bonfante, Estevam A; Martins, Leandro M; Silva, Nelson R F A; Marotta, Leonard; Coelho, Paulo G
The reliability and failure modes of molar crowns supported by three different implant-supported designs were tested according to the following groups: group 1, one standard-diameter implant (3.75 mm); group 2, one narrow-diameter implant (3 mm); and group 3, two narrow-diameter implants (3 mm). Loads were applied as mouth-motion cycles using a step-stress accelerated life-testing method. ? values for groups 1 and 3 (1.57 and 2.48, respectively) indicated that fatigue accelerated the failure of both groups, but not for group 2 (0.39). Abutment screw failure was the chief failure mode. Strength and reliability were significantly higher for groups 1 and 3 compared to group 2
PMID: 22146255
ISSN: 0893-2174
CID: 155459

Oral maxillary squamous carcinoma: an indication for neck dissection in the clinically negative neck

Montes, David M; Carlson, Eric R; Fernandes, Rui; Ghali, G E; Lubek, Joshua; Ord, Robert; Bell, Bryan; Dierks, Eric; Schmidt, Brian L
BACKGROUND: This multicenter study was undertaken to characterize the metastatic behavior of oral maxillary squamous carcinoma and to determine the role of selective neck dissection. METHODS: A retrospective, multicenter study of patients surgically treated for oral maxillary squamous carcinoma was completed. Data collected included primary tumor location, cervical lymph node status, and neck failure rate. RESULTS: The study included 146 patients. The adjusted regional metastatic rate was 31.4%. Of those N0 (clinically negative) necks treated with or without neck dissection, 14.4% developed cervical metastasis. Within the cohort, 7.5% of patients died with distant disease. The regional salvage rate was 52.9%. None of the patients with locoregional failures were salvaged. CONCLUSIONS: Maxillary palatal, alveolar, and gingival squamous carcinomas exhibit aggressive regional metastatic behavior. Surgical salvage rates for neck failure are low; therefore, selective neck dissection (levels I-III) is recommended at the time of resection of T2, T3, and T4 maxillary squamous carcinomas.
PMID: 21990223
ISSN: 1043-3074
CID: 155553

Incidence of cleft pathology in greater new orleans before and after hurricane katrina

Goenjian, Haig A; Chiu, Ernest S; Alexander, Mary Ellen; St Hilaire, Hugo; Moses, Michael
Background : Reports after the 2005 Hurricane Katrina have documented an increase in stress reactions and environmental teratogens (arsenic, mold, alcohol). Objective : To assess the incidence of cleft pathology before and after the hurricane, and the distribution of cleft cases by gender and race. Methods : Retrospective chart review of cleft lip with or without cleft palate (CL/P) and cleft palate (CP) cases registered with the Cleft and Craniofacial Team at Children's Hospital of New Orleans, the surgical center that treated cleft cases in Greater New Orleans between 2004 and 2007. Live birth data were obtained from the Louisiana State Center for Health Statistics. Results : The incidence of cleft cases, beginning 9 months after the hurricane (i.e., June 1, 2006) was significantly higher compared with the period before the hurricane (0.80 versus 1.42; p = .008). Within racial group comparisons showed a higher incidence among African Americans versus whites (0.42 versus 1.22; p = .01). The distribution of CL/P and CP cases by gender was significant (p = .05). Conclusion : The increase in the incidence of cleft cases after the hurricane may be attributable to increased stress and teratogenic factors associated with the hurricane. The increase among African Americans may have been due to comparatively higher exposure to environmental risk factors. These findings warrant further investigation to replicate the results elsewhere in the Gulf to determine whether there is a causal relationship between environmental risk factors and increased cleft pathology.
PMID: 21303264
ISSN: 1055-6656
CID: 169964

Litigation and legislation. Don't bug me

Jerrold, Laurance
PMID: 22051496
ISSN: 1097-6752
CID: 1992322

Experience with developmental facial paralysis: Part I. Diagnosis and associated stigmata

Terzis, Julia K; Anesti, Katerina
BACKGROUND: This study is a thorough literature review of the clinical presentation and evaluation of developmental facial paralysis, with a systematic description of the various stigmata and associated anomalies. It is hoped that this approach will facilitate the differentiation of developmental facial paralysis from other causes of facial paralysis present at birth. METHODS: Forty-two cases of developmental facial paralysis were identified in a retrospective clinical review (1980 to 2010); 34 were children (80.95 percent; age, 8+/-6 years) and eight were adults (19.05 percent; age, 27+/-12 years). Thirty-one patients had simple developmental paralysis, and two patients had developmental unilateral lower lip palsy. There were nine patients with associated anomalies or craniofacial syndromes. Five of these patients had multiple cranial nerve deficits. RESULTS: Analysis of the various stigmata revealed significant correlation between the presence of developmental facial paralysis and amblyopia, hypoplastic facial nerve on imaging or surgical exploration, lower alar atresia, and skin changes (i.e., acne), but not the ear abnormalities. CONCLUSIONS: Early targeted screening and diagnosis, with prompt specialized treatment, improves the physical and emotional development of children with developmental facial paralysis and reduces the prevalence of amblyopia and other sequelae of the condition, thus facilitating reintegration among their peers. Given the dramatic presentation of this condition, accurate and reliable guidelines are necessary to facilitate early diagnosis, initiate appropriate therapy, and provide support and counseling to the family.
PMID: 22030508
ISSN: 1529-4242
CID: 463662

3D Volume Assessment Techniques and Computer-Aided Design and Manufacturing for Preoperative Fabrication of Implants in Head and Neck Reconstruction

Patel, Ashish; Otterburn, David; Saadeh, Pierre; Levine, Jamie; Hirsch, David L
Cases in subdisciplines of craniomaxillofacial surgery-corrective jaw surgery, maxillofacial trauma, temporomandibular joint/skull base, jaw reconstruction, and postablative reconstruction-illustrate the ease of use, cost effectiveness, and superior results that can be achieved when using computer-assisted design and 3D volumetric analysis in preoperative surgical planning. This article discusses the materials and methods needed to plan cases, illustrates implementation of guides and implants, and describes postoperative analysis in relation to the virtually planned surgery
PMID: 22004861
ISSN: 1558-1926
CID: 139041

Alveolar buccal bone maintenance after immediate implantation with a surgical flap approach: a study in dogs

Coelho, Paulo G; Marin, Charles; Granato, Rodrigo; Bonfante, Estevam A; Lima, Cirilo P; Oliveira, Sergio; Dohan Ehrenfest, David M; Suzuki, Mercelo
This study evaluated buccal bone maintenance after implantation with a surgical flap approach immediately following tooth extraction in a dog model. Mandibular premolars of six dogs were extracted, and threaded implants of 4-mm diameter and 8-mm length with as-machined and dual acid-etched surfaces were placed through balanced procedures in the distal root extraction sockets with a full-thickness flap design. Submerged healing was allowed for 4 weeks, and following euthanization, bone-to-implant contact and buccal and lingual bone loss were evaluated. None of the parameters evaluated were indicative of an effect of implant surface in hindering bone loss around immediately placed implants.
PMID: 22140672
ISSN: 0198-7569
CID: 160702

Surgical management of facial nerve paralysis in the pediatric population

Barr, Jason S; Katz, Karin A; Hazen, Alexes
BACKGROUND: In the pediatric patient population, both the pathology and the surgical managements of seventh cranial nerve palsy are complicated by the small size of the patients. Adding to the technical difficulty is the relative infrequency of the diagnosis, thus making it harder to become proficient in the management of the condition. The magnitude of the functional and aesthetic deficits these children manifest is significantly troubling to both the patient and the parents, which makes immediate attention, treatment, and functional restoration essential. METHODS: A literature search using PubMed (http://www.pubmed.org) was undertaken to identify the current state of surgical management of pediatric facial paralysis. RESULTS: Although a multitude of techniques have been used, the ideal reconstructive procedure that addresses all of the functional and cosmetic needs of these children has yet to be described. Certainly, future research and innovative thinking will yield progressively better techniques that may, one day, emulate the native facial musculature with remarkable precision. CONCLUSION: The necessity for surgical intervention in children with facial nerve paralysis differs depending on many factors including the acute/chronic nature of the defect as well as the extent of functional and cosmetic damage. In this article, we review the surgical procedures that have been used to treat pediatric facial nerve paralysis and provide therapeutic facial reanimation
PMID: 22075352
ISSN: 1531-5037
CID: 141490

Influence of implant design on the biomechanical environment of immediately placed implants: computed tomography-based nonlinear three-dimensional finite element analysis

Pessoa, Roberto S; Coelho, Paulo G; Muraru, Luiza; Marcantonio, Elcio Jr; Vaz, Luis Geraldo; Vander Sloten, Jos; Jaecques, Siegfried V N
PURPOSE: To evaluate the influence of different implant designs on the biomechanical environment of immediately placed implants. MATERIALS AND METHODS: Computed tomography (CT)-based finite element models comprising a maxillary central incisor socket and four commercially available internal-connection implants (SIN SW, 3i Certain, Nobel Replace, and ITI Standard) of comparable diameters and lengths were constructed. Biomechanical scenarios of immediate placement, immediate loading, and delayed loading protocols were simulated. Analysis of variance at the 95% confidence level was used to evaluate peak equivalent strain (EQV strain) in bone and bone-to-implant relative displacement. RESULTS: Loading magnitude (77.6%) and the clinical situation (15.0%) (ie, presence or absence of an extraction socket defect, condition of the bone-to-implant interface) presented the highest relative contributions to the results. Implant design contributed significantly to strains and displacements in the immediate placement protocol. Whereas a greater contribution of implant design was observed for strain values and distributions for immediately placed and immediately loaded protocols, a smaller contribution was observed in the delayed loading scenario. CONCLUSION: Implant design contributes significantly to changing biomechanical scenarios for immediately placed implants. The results also suggest that avoiding implant overloading and ensuring high primary implant stability are critical in encouraging the load-bearing capability of immediately placed implants.
PMID: 22167434
ISSN: 0882-2786
CID: 160701