Positioning accuracy assessment of minimally invasive percutaneous injection techniques for the treatment of temporomandibular disorders.

OBJECTIVE: The aim of the present study was to evaluate the accuracy of an extraoral CBCT-planned 3D-printed surgical guide aimed to percutaneous injection of substances into the temporomandibular joint (TMJ) and the lateral pterygoid muscle (LPM). METHODS: Nine human cadaver heads were used. Pre-planning CBCT and facial scans were obtained and three percutaneous injection sites were planned: one for the lower compartment of the TMJ and two for the LPM. A digital surgical guide was then designed with small titanium sleeves and printed by a 3D printer. After the injections, new CBCT scans with the needles in place were obtained in order to assess the accuracy of the procedure in relation to the virtual planning. RESULTS: The mean values for angle deviation were very low (range 1.13o-4.08o), the same happening for the mean difference in the length reached (range 1.82-2.64 mm), as well as for the mean difference in the needle tip dislocation (range 0.94-2.03 mm). CONCLUSION: The guide seems to be a reliable tool for accurate percutaneous injection of drugs into the inferior compartment of the TMJ and the LPM. Further studies are necessary to test the efficacy and validate the method in an in vivo study.

KRAS mutations in implant-associated peripheral giant cell granuloma.

OBJECTIVES: To investigate the molecular pathogenesis of implant-associated peripheral giant cell granuloma (IA-PGCG). METHODS: A convenience sample of 15 IA-PGCG cases was selected. Hotspot mutations of KRAS, FGFR1, and TRPV4 genes, previously reported in conventional giant cell lesions of the jaws, were investigated by Sanger sequencing. As these mutations could activate MAPK/ERK pathway, the expression of phospho-ERK1/2 was also evaluated by immunohistochemistry. RESULTS: KRAS mutations were detected in 8/15 (53.4%) samples. Similar to conventional peripheral giant cell granuloma, the KRAS mutations most frequently occurred in codon 146 (p.A146V, n = 3), followed by codon 12 (p.G12A and p.G12D, n = 1 each) and codon 14 (p.V14L, n = 1). Variants of unknown significance (VUS) were also detected in two cases, affecting codons 37 (p.E37K) and 127 (p.T127I). All samples showed wild-type (WT) sequences for FGFR1 and TRPV4 genes. Consistent with MAPK/ERK pathway activation, all mononuclear cells of the lesion showed strong staining for phospho-ERK1/2 protein in the immunohistochemical analysis. CONCLUSIONS: KRAS mutations and activation of the MAPK-ERK signaling pathway occur in IA-PGCG. This is the first study to demonstrate cancer-associated gene mutations in a non-neoplastic reactive condition associated with dental implants.

Survival and complications of zygomatic implants: a systematic review.

PURPOSE: This systematic review attempted to answer the focused questions: "What is the survival rate of zygomatic implants (ZIs)?" and "What are the most common complications related to surgery of zygomatic implants?" METHODS: An electronic search without date or language restrictions was undertaken in PubMed in March 2012. Titles and abstracts from these results (n = 123) were read for identifying studies that meet the eligibility criteria. Eligibility criteria included studies reporting clinical series of zygomatic implants (ZIs). Because of the scarcity of articles with high-level grades of evidence, all articles, including studies with few case reports, were considered for inclusion. All reference lists of the selected and review studies were hand-searched for additional papers that might meet the eligibility criteria. Simple case report articles were not included. Review articles without original data were excluded. Quantitative data extracted from the included studies that provided data for the period of failure of ZIs were used for the calculation of interval survival rate during each follow-up period and cumulative survival rate (CSR) over a 12-year period. RESULTS: Thirty-seven studies were identified without repetition and five more studies were included by hand-searching, giving a total of 42; 12 evaluated the use of ZI applied with immediate function protocols and 3 for rehabilitating patients after maxillary resections for tumor ablations. These latter three studies showed smaller ZI success. Postoperative complications reported were as follows: 70 cases of sinusitis, 48 of soft tissue infection, 15 of paresthesia, and 17 cases of oroantral fistulas. However, this number may be underestimated, since most of the studies did not mention the presence or absence of these complications. Most ZI failures were detected at the abutment connection phase (6 months after the surgery of implant placement) or before. The CSR over a 12-year period was 96.7 %. CONCLUSIONS: Despite the high survival rate observed, there is an impending need for conducting randomized controlled clinical trials to test the efficacy of these implants in comparison with the other techniques to treat the atrophic maxilla. Thus, the findings reported in the review must be interpreted with considerable caution. Moreover, more studies with longer follow-up periods involving adequate number of ZIs are needed. This will help to obtain a better understanding of the survival of ZIs in a long term. It is suggested that multicenter, randomized controlled clinical trials and longer clinical studies should be implemented in this area, before recommending routine use of ZIs for patients could be given. The placement of zygomatic implants requires very experienced surgeons because it is not risk free since delicate anatomic structures such as the orbita and brain may be involved.

Open versus closed reduction: comminuted mandibular fractures.

PURPOSE: The purpose of the study was to review the literature regarding the evolution of current thoughts on management of comminuted mandibular fractures (CMFs). METHODS: An electronic search in PubMed was undertaken in May 2012. The titles and abstracts from these results were read to identify studies within the selection criteria. Eligibility criteria included studies published in English or German reporting clinical series of CMFs. RESULTS: The search strategy initially identified 409 studies. Fifteen studies were identified without repetition within the selection criteria. One case report article showing significance in the development of treatment techniques was included. Additional hand-searching yielded five additional papers. Thus, a total of 21 studies were included. CONCLUSIONS: Open reduction and internal fixation (ORIF) in cases of CMFs are indicated in (a) severe injuries with significant displacement to allow restoration of pretraumatic anatomic relationships, (b) in the edentulous and semi-dentate patient, who may benefit from ORIF of CMFs when stable occlusal relationships are absent, and (c) in cases with multiple fractures of the midface, in which the mandible has to serve as a guide to reposition the midfacial bones. However, there is still a place for closed reduction/conservative treatment (CTR). ORIF in CMFs is not indicated in cases of minimally displaced comminuted fractures that could easily and adequately be treated with CTR. If the surgical team is not well versed in the nuances of rigid internal fixation, or the necessary equipment is not available, it is far better to do simple CTR. However, it would be more reasonable to refer the patient to a hospital that can provide means of ORIF in cases of clear indication of its use in CMFs. In cases where ORIF is indicated, stabilization by compression or any other form of load-sharing osteosynthesis is obviously contraindicated because small fragments cannot be compressed and are not capable of sharing loads. Thus, the ORIF of CMFs is best performed using load-bearing osteosynthesis; most experience has been gained with 2.7-mm reconstruction plates. External pin fixation could be used in cases when there is so much comminution, soft tissue disruption (mostly gunshot wounds), and there are inadequate teeth on either side of the comminuted fracture to control the spatial relationship of the remaining mandibular fragments with maxillomandibular fixation (MMF).

1,454 mandibular fractures: a 3-year study in a hospital in Belo Horizonte, Brazil.

OBJECTIVE: To analyze the mandibular fractures which presented over a 3-year period at an emergency hospital in Belo Horizonte, Brazil. METHODS: The data collected included age, sex, aetiology, date of trauma, associated maxillofacial trauma, anatomic site of fracture, and treatment. The analysis involved descriptive statistics and the Pearson's chi-square, Bonferroni, Kolmogorov-Smirnov, Kruskal-Wallis and Mann-Whiney tests, and analysis of variance. RESULTS: There were 1,454 mandibular fractures in 1,023 patients. Males of 20-29 years of age sustained the majority of fractures. Traffic accidents were the major causes of trauma, followed by violence and falls. A high incidence of fractures in women due to violence was observed. The condyle region was found to be the most common fracture site in the mandible. A surgical approach was performed in most cases. There were more accidents causing mandibular fractures on the weekends. CONCLUSION: The individuals with mandibular fractures due to "traffic accidents" were younger than those due to "violence" and "falls". There was a significant statistical association between age and aetiology as well as between sex and aetiology of mandibular fractures.

Considerations of maxillary tuberosity fractures during extraction of upper molars: a literature review.

BACKGROUND: Maxillary tuberosity fractures during molar teeth extraction commonly occur in dental practice; however, very few cases have been reported and discussed in the literature. A correct preoperative radiographic interpretation, coupled with the anatomical knowledge of the structures involved, is essential to prevent such complications. AIM: The purpose of this paper is to enumerate the predisposing and etiological factors of maxillary tuberosity fractures during the extraction of upper molars, discuss the procedures that need to be taken when small or large fractured fragments of the tuberosity are evident during surgery, and suggest appropriate recommendations. This study is based on a thorough literature review. CONCLUSIONS: Upon discovering that a maxillary tuberosity has fractured, the dentist must first halt the procedure before inadvertent laceration of the adjoining soft tissue occurs and then determine the extent of the fracture by palpating the mobile fragment. After performing the dissection of the soft tissues, immediate removal of the small fractures, including the tooth with small bony fragments, may be the best option, because of the difficulty incurred when attempting to retain the bone. When a large bony fragment is present, it is recommended (i) that the extraction be abandoned and surgical removal of the tooth be performed using root sectioning, (ii) that the dentist tries to detach the fractured tuberosity from the roots, or (iii) that the dentist stabilizes the mobile part(s) of the bone by means of a rigid fixation technique for 4-6 weeks and, at a future moment, attempts a surgical removal without the use of a forceps.

Morphological variation in dentate and edentulous human mandibles.

PURPOSE: The 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. METHODS: Eighty 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. RESULTS: Considerable 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. CONCLUSIONS: The 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.

Neurofibromatosis type 1 associated with bilateral central giant cell granuloma of the mandible.

Neurofibromatosis type 1, or von Recklinghausen disease, is one of the most common hereditary neurocutaneous disorders in humans. Clinically, Neurofibromatosis type 1 is characterized by café-au-lait spots, freckling, skin neurofibroma, plexiform neurofibroma, bony defects, Lisch nodules and tumors of the central nervous system. Central giant cell granuloma is a benign central lesion of bone, primarily involving the jaws, of variably aggressive nature characterized by aggregates of multinucleated giant cells in a background of cellular vascular fibrous connective tissue and spindle-shaped mononuclear stromal cells. The association between neurofibromatosis and central giant cell granuloma has been reported in the literature. A case of mandibular bilateral central giant cell granuloma in a patient with Neurofibromatosis type 1 was conservatively but successfully treated by adequate surgical curettage of mandibular bone lesions.

Paradental (mandibular inflammatory buccal) cyst.

The paradental cyst is commonly misinterpreted when associated with atypical clinical and radiographic characteristics, in turn causing diagnostic problems. For this reason, the study of the differential diagnosis of this lesion has become extremely important. In addition, the correlation of clinical, histologic, and radiographic findings are also of great value in obtaining accurate diagnoses. The minor variations in the clinical appearance of paradental cysts make it feasible to consider the two main groups of cysts separately: those associated with 1st and 2nd permanent molars of the mandible and those associated with the 3rd mandibular molar. Moreover, this distinction in localization may well dictate the necessary treatment. Bearing in mind the minor clinical variations, the present article aims to discuss the differential diagnosis of this lesion and its different possible treatments by presenting a case report to illustrate the findings.

Primary and secondary impaction of four primary molar teeth in a single patient / Retención primaria y secundaria de los cuatro primeros molares en un paciente

The lack of eruption of a primary tooth can be considered rare. In primary impaction, the primary tooth not only has never appeared in the oral cavity, but also is always covered by a more or less thick layer of bone. Secondary impaction, which is relatively more common, denotes teeth that at one time erupted into the mouth, but subsequently clinically appear to have receded from this position. The purpose of this paper is to present a case of primary and secondary impaction of four primary molar teeth in a single patient(AU)

La falta de erupción de un diente temporal puede ser considerada una situación rara. En la retención primaria, no sólo el diente temporal nunca ha aparecido en la cavidad bucal, sino que también está cubierto por una capa más o menos gruesa del hueso. La retención secundaria, que es relativamente más común, se refiere a los dientes que inició su erupción en la boca, pero clínicamente quedan atrapados en esta posición. El propósito de este trabajo es presentar un caso de retención primaria y secundaria de cuatro molares primarios en un paciente(AU)

Facial fractures in the elderly: a retrospective study in a hospital in Belo Horizonte, Brazil.

BACKGROUND: An increasing incidence of maxillofacial trauma in the elderly has been noted, as a consequence of increased longevity, resulting in a higher percentage of elderly people in the population. METHODS: A retrospective study was undertaken to assess facial fractures in elderly presenting during the period 2000 to 2002 in Belo Horizonte, Brazil. The data collected included age, gender, etiology, date of trauma, maxillofacial trauma, anatomic site of fracture, and treatment. The statistical analysis involved evaluation of measures of central tendency and variability and calculation of proportions. RESULTS: It encountered 165 facial fractures in 122 elderly aged 60 years or older. The majority of fractures were sustained by elderly in the age group 60 years to 69 years. Falls was the major cause of trauma followed by car accidents. The mandible was found to be the most common fractured bone in the facial skeleton, followed by the zygomatic complex. A conservative approach was accomplished in the most of cases. CONCLUSION: Gender was associated with the presence or absence of fractures and with the etiology. There was no association between age and fractures. No association was found between etiology and age for women and men. The proportion of fractures of the zygomatic arch, mandible body, and parasymphysis treated surgically were statistically higher than the same proportion among the cases of other fractures. The fractures of the nose were more often treated conservatively than other fractures.

Prevalence of enamel pearls in teeth from a human teeth bank.

Enamel pearls are anatomical structures that can bring about clinical implications if associated with the retention of plaque, in turn resulting in periodontal disease. In an attempt to avoid periodontal disease, the removal and treatment of these enamel pearls, may be a necessity in some circumstances. A total of 45,785 extracted teeth from a human teeth bank were analyzed for the presence of enamel pearls. The most prevalent anatomical location of enamel pearls was the permanent maxillary first and second molar region. An association between the prevalence of enamel pearls and dental class (P < 0.001) was observed, most frequently in the maxillary molars. In the maxillary molars, the most prevalent anatomical location of enamel pearls in the first and second molars was the furcation between the distobuccal and palatal roots. Enamel pearls are a common observation in molars in general, but are most commonly found in maxillary molars.

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 patient's 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.

Facial fractures in children and adolescents: a retrospective study of 3 years in a hospital in Belo Horizonte, Brazil.

AIM: The purpose of this study was to review the etiology, incidence and treatment of selected oral and maxillofacial fractures in children in Belo Horizonte, Brazil, during a period of 3 years. MATERIALS AND METHODS: The data collected for this study included age, gender, etiology, date of trauma, associated maxillofacial trauma, anatomic site of fracture and treatment. The analysis involved descriptive statistics and chi-squared test, Bonferroni test, Kolmogorov-Smirnov, Kruskal-Wallis and Mann-Whiney tests and analysis of variance. RESULTS AND CONCLUSIONS: This study examined 566 facial fractures in 464 children of 18 years of age or less. The majority of fractures were observed in children within the age group of 13-18 years of age. Bicycle accidents were the major cause of trauma, followed by falls. The mandible was found to be the most common fractured bone in the facial skeleton, followed by the nose. A conservative approach was applied in most cases.

Anatomical variation in the position of the greater palatine foramen.

The present study measured the position of the greater palatine foramen relative to adjacent anatomical landmarks in Brazilian skulls. The perpendicular distance of the greater palatine foramen to the midline maxillary suture in Brazilian skulls was about 14 mm and the distance of greater palatine foramen to the incisive foramen was approximately 36 mm. The distance of greater palatine foramen to the posterior border of the hard palate was approximately 3 mm, and the mean angle between the midline maxillary suture and the line from the incisive foramen and the greater palatine foramen was 22.71 degrees . In almost 70% of the cases, the greater palatine foramen opened in an anterior direction. The mean palatine length was approximately 52 mm. In the greater majority of the skulls (93.81%), the greater palatine foramina were opposite or distal to the maxillary third molar. These data will be helpful in comparing these skulls to those from various other regions as well as comparing skulls of different races. It can also provide professionals with anatomical references, in order to block the maxillary division of the trigeminal nerve through the greater palatine foramen. Our results would help clinicians locate the greater palatine foramen in patients with and without upper molars.

Considerations of mandibular angle fractures during and after surgery for removal of third molars: a review of the literature.

BACKGROUND: Angle fractures are quite common considering that the angle of the mandible forms an area of lower resistance which contains a thicker upper border, a thin basilar bone, and the presence of an impacted mandibular third molar. Common complications of mandibular third molar surgery include alveolar osteitis (dry socket), secondary infection, nerve dysfunction, and hemorrhage. Reports of mandibular fracture during and after third molar removal are uncommon. PURPOSE: The purpose of this paper is to discuss the risk and predisposing factors that should be analyzed regarding the possibility of immediate and late mandibular angle fractures and their need for surgical treatment as a means through which to remove impacted molars. This study is based on a thorough review of the literature as well as on one immediate and one late mandibular angle fracture as described by the authors' own personal experience. CONCLUSIONS: The danger of an immediate jaw fracture can be avoided by means of proper instrumentation and by refraining from excessive force on the bone. The tooth should be sectioned in such a way as to minimize the extent of bone removal and force caused by instrumentation. The danger of a late jaw fracture can be avoided by precise diagnosis in cases of patients over 25 years of age, particularly men, whose tooth roots are superimposed on or adjacent to the inferior alveolar canal on a panoramic image, any local pathology and systemic disease or medications which may impair bone strength, and patients who present bruxism and are active athletes.

Maxillary sinus aplasia.

PURPOSE: A case of unilateral aplasia is reported. Associated anatomical anomalies and review of the literature is described, and a comparison with maxillary sinus hypoplasia is made. PATIENT: A 40-year-old male was complaining of an esthetic "defect" in his face. There was an antero-posterior depression in the left infraorbital region. Computed tomography showed absence of the left maxillary antrum, uncinate process, and maxillary infundibulum. The ipsilateral orbit was increased in volume inferiorly, and the inferior margin was immediately adjacent to the root of the inferior turbinate. The left inferior and middle turbinate was hyperplastic. The nasal septum was a little dislocated to the ipsilateral side. There was no history of antecedent sinusitis or surgery, and no evidence of systemic disease. An appositional en bloc autogenous bone graft was placed on the left infraorbital depression. CONCLUSIONS: With precise computed tomography assessments, a maxillary sinus hypoplasia or aplasia can be diagnosed and distinguished from other maxillary sinus anomalies, and may help the surgeon to plan his surgical procedure and identify the limits of dissection accordingly. The condition can also "cause" an esthetical deficit in the infraorbital/zygomatic region, which can be resolved with an appositional graft.

An expanded odontogenic myxoma in maxilla.

Odontogenic myxomas are considered to be a benign odontogenic tumor with locally aggressive behavior, non-metastasizing neoplasm of the jaw bones. It derives from the dental mesenchyme or periodontal ligament. Despite the benign nature of these lesions, there is a high rate of local recurrence after curettage alone and in certain cases requires adequate resection. This paper describes a case of a large odontogenic myxoma in the maxilla, emphasizing a discussion on the differential diagnosis related to radiological findings and the surgical treatment.

Traumatic displacement of maxillary permanent incisor into the nasal cavity.

PURPOSE: The 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. PATIENT: A 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. CONCLUSIONS: Because 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.