Antônio Luís Neto Custódio

Morphological variation in dentate and edentulous human mandibles

PurposeThe aim of the study was to examine the different morphometric variations of the human mandibles, comparing between males and females in dentate and edentulous mandibles.MethodsEighty adult human dry mandibles were studied. Thirty-two variations were evaluated according to the presence and absence of teeth. Kolmogorov–Smirnov test was performed to evaluate the normal distribution of the morphometric variables. Levene test evaluated homoscedasticity. Student t tests and Mann–Whitney U tests, when indicated, were performed to compare each of the morphometric variables between dentate and edentulous mandibles. Statistical differences were considered when the P value was less than 0.05.ResultsConsiderable numbers of measurements were statistically significantly different when comparing the influence of dental status on the anatomical measurements; the position and anatomical relations of the mental foramen and overall dimensions of the mandible are especially influenced. Only a few measurements were statistically significantly different in the comparison between males and females.ConclusionsThe results of this research showed that the presence or absence of the teeth can alter mandibular shape and that mandibular edentulism may be associated with specific shape changes in the mandible. The dental status has a higher influence on the mandibular anatomy than the difference in gender.

Mandibular fractures associated with endosteal implants

PurposeThe purpose of this study is to report four cases of mandibular fractures associated with endosteal implants and to discuss prevention and treatment of these types of fractures.DiscussionTo evaluate whether the patients anatomy allows insertion of implants, radiological exams that demonstrate the height and the labial–lingual width are needed. To reduce the potential fracture problem, the mandible can be restrengthened with bone grafting techniques. The treatment of a fracture in an atrophic mandible is always a challenge because of the diminished central blood supply, the depressed vitality of the bone, and the dependence on the periosteal blood supply. The basic principles in fracture treatment are reduction and immobilization of the fractured site for restoration of form and function.ConclusionsIf implants are placed in severe atrophic mandible, iatrogenic fracture of the mandible may occur during or after implant surgery because implant placement weakens the already-compromised mandible. A few millimeters of cortical bone should remain on both the labial and the lingual sites after the hole for insertion of an implant has been drilled. A 3-D surgical planning should be recommended at least in severe atrophic mandibles in order to prevent a severe reduction of bone tissue.

Zygomatic implants: a critical review of the surgical techniques

PurposeThe purpose of the present study is to identify and describe the different surgical techniques for placement of zygomatic implants reported in the literature and discuss the differences between them.MethodsAn electronic search was undertaken in July 2011. The titles and abstracts from these results (n = 130) were read for identifying studies, which reported different surgical techniques for placement of zygomatic implants, which resulted in 41 articles.ResultsFive different surgical approaches were identified: (1) the classical approach, (2) the sinus slot technique, (3) the exteriorized approach, (4) the minimally invasive approach by the use of custom-made drill guides, and (5) the computer-aided surgical navigation system approach. When the maxilla is severely resorbed, the concavity formed by the ridge crest is small, and the original classical technique should be used. When maxillary resorption generates a large concavity, it would be better to exteriorize the zygomatic implant. The externalized technique has fewer surgical steps than the classical and sinus slot methods, is less invasive, and reduces surgical time. It is recommended that utilization of the sinus slot technique together with the CT-based drilling guide would enhance the final results. Although the technique that uses the computer-aided surgical navigation system approach may produce an improved precision in the clinical procedure, its use is expensive, prolongs the operation time, and is limited to centers that have the necessary equipment for the surgery.ConclusionsPreference for one technique over the other should take into consideration the concavity formed by the ridge crest, maxillary sinus, and region of implant insertion in the zygomatic bone.

Accuracy Evaluation of Computed Tomography–Derived Stereolithographic Surgical Guides in Zygomatic Implant Placement in Human Cadavers

Presurgical planning is essential to achieve esthetic and functional implants. For implant planning and placement, the association of computer-aided design (CAD) and computer-aided manufacturing (CAM) techniques furnishes some advantages regarding tridimensional determination of the patients anatomy and fabrication of both anatomic models and surgical guides. The goal of this clinical study was to determine the angular deviations between planned and placed zygomatic implants using stereolithographic surgical guides in human cadavers. A total of 16 zygomatic implants were placed, 4 in each cadaver, with the use of stereolithographic (SLA) surgical guides generated by computed tomography (CT). A new CT scan was made after implant insertion. The angle between the long axis of the planned and actual implants was calculated. The mean angular deviation of the long axis between the planned and placed implants was 8.06 ± 6.40 (mean ± SD) for the anterior-posterior view, and 11.20 ± 9.75 (mean ± SD) for the caudal-cranial view. Use of the zygomatic implant, in the context of this protocol, should probably be reevaluated because some large deviations were noted. An implant insertion guiding system is needed because this last step is carried out manually. It is recommended that the sinus slot technique should be used together with the CT-based drilling guide to enhance final results. Further research to enhance the precision of zygomatic implant placement should be undertaken.

Orthodontic or surgically assisted rapid maxillary expansion

PurposeThe purpose of this study was to present, compare, and discuss the techniques for rapid maxillary expansion.DiscussionThe isolated transverse maxillary deficiency can be treated either orthodontically or surgically with rapid palatal expansion. In children and adolescents, conventional orthodontic rapid maxillary expansion has been successful when used before sutural closure. On the other hand, in skeletally mature patients, the possibility of successful maxillary expansion decreases as sutures close and the resistance to mechanical forces increases.ConclusionsThe selection of an expansion technique depends on a number of factors. It is more likely to advocate surgery as the patient’s age, transverse needs, or acceptance of the idea of surgery increases.

Optic, Oculomotor, Abducens, and Facial Nerve Palsies After Combined Maxillary and Mandibular Osteotomy: Case Report

Le Fort I osteotomy is a standard technique for thesurgical management of dentofacial anomalies andcan allow for many other operations. One of the keysteps in this type of osteotomy is pterygomaxillarydisjunction. Although the exact mechanisms leadingto optic nerve injury are still unclear, atypical fracturepatterns that extend upward to the skull base fromthe site of pterygomaxillary separation have been re-searched by many investigators.

Traumatic displacement of maxillary permanent incisor into the nasal cavity

PurposeThe purpose of this paper was to describe a case of unviable alveolar repositioning of an intruded tooth into the nasal cavity and to bring the subject of intrusive tooth injury among patients with dentoalveolar fractures to the attention of trauma surgeons.PatientA 26-year-old male was involved in a car accident and crashed his mouth against the dashboard due to sudden deceleration. Intraoral examination revealed an anterior maxillary dentoalveolar fracture and absence of the central maxillary incisors, right lateral maxillary incisor, and left maxillary canine. Computed tomography showed a dislocated tooth in the nasal cavity. The “missing” left maxillary canine was easily recovered from the floor of the left nostril.ConclusionsBecause complete dislocation of a tooth can cause a frontal sinus abscess, an airway complication, a respiratory tract obstruction, and a complicated lung abscess or sinusitis, anytime a tooth is not accounted for after a dentoalveolar trauma, the possibility that it has been fully intruded should be considered. Computed tomographic scan should be a routine diagnostic study in all cases with associated missing anatomical structures in the oral and maxillofacial region. The need to involve the dental professional in the initial assessment of dental trauma in emergency rooms in hospitals is important in order to identify how many teeth might be missing after dental trauma and to correctly reposition the avulsed teeth when possible.

Styloid Process of the Temporal Bone: Morphometric Analysis and Clinical Implications

Objective. To evaluate measures of the styloid process (SP) in Brazilian dry skulls. Methods. This study involves measurements of two points (lateral end posterior views) of 15 dry skulls held by the Morphology Department, Institute of Biological Sciences of Federal University of Minas Gerais. Results. There was a large variability for the length of left and right sides (in lateral and posterior views) of the styloid process. From the lateral view of the left and right styloid, the length of the SP ranged, respectively, from 10.22 mm to 69.73 mm and from 8.30 mm to 63.77 mm. From a posterior view of the left and right sides of the skulls, the values range, respectively, from 15.57 mm to 69.51 mm and from 15.64 mm to 69.44 mm. Conclusion. We believe that this study provides additional information about the frequency of elongated SP among the Brazilian population.