Current Strategies for Treatment of Mandibular Fractures With Plate Osteosynthesis: A European Prospective Study.

PURPOSE: The training and preferences of surgeons influence the type of surgical treatment for mandibular fractures. This multicentre prospective study analyzed the current treatment strategies and outcomes for mandibular fractures with open reduction and internal fixation (ORIF). MATERIAL AND METHODS: This prospective study included patients aged ≥16 years who underwent ORIF for mandibular fractures in 12 European maxillofacial centers. Age, sex, pretrauma dental status, fracture cause, site and type, associated facial fractures, surgical approach, plate number and thickness (≤1.4 or ≥1.5 mm), duration of postoperative maxillomandibular fixation, occlusal and infective complications at 6 weeks and 3 months, and revision surgeries were recorded. RESULTS: Between May 1, 2021 and April 30, 2022, 425 patients (194 single, 182 double, and 49 triple mandibular fractures) underwent ORIF for 1 or more fractures. Rigid osteosynthesis was performed for 74% of fractures and was significantly associated with displaced ( P =0.01) and comminuted ( P =0.03) fractures and with the number of nonsurgically treated fracture sites ( P =0.002). The angle was the only site associated with nonrigid osteosynthesis ( P <0.001). Malocclusions (5.6%) and infective complications (5.4%) were not associated with osteosynthesis type. CONCLUSION: Rigid osteosynthesis was the most frequently performed treatment at all fracture sites, except the mandibular angle, and was significantly associated with displaced and comminuted fractures and the number of nonsurgically treated fracture sites. No significant differences were observed regarding postoperative malocclusion or infections among osteosynthesis types.

Patient's perception of recovery following surgical removal of mandibular third molars. A prospective european multi-center study.

This study evaluated patient's perception of recovery following surgical removal of mandibular third molars (SRM3s) including analyze of potential risk factors associated with impaired convalescent. Patient related parameters combined with preoperative questionnaires including Modified Dental Anxiety Scale, Oral Health Impact Profile-14, and Decayed, Missing, Filled Teeth index were correlated with questionnaires assessing pain, swelling, trismus, sick leave, social and working isolation, physical appearance, eating and speaking ability, diet variations, sleep impairment, impaired sensation of the lip, chin, and tongue, one month following SRM3s. Totally, 412 patients (223 females, 189 males) with mean age of 29.4 years were included. Treatment satisfaction and willingness to undergo similar surgery were reported by 92% and 95%, although 21% reported that the surgery and postoperative period had been worse than expected. Mean days with pain, sick leave, and swelling were 3.6, 2.1, and 3.6, respectively. Preoperative symptoms, dental anxiety level, and prolonged surgical time were associated with increased pain and swelling (P < 0.05). Pell and Gregory classification (I-IIIC) were associated with impaired sensation of the lower lip and chin (P < 0.05). Consequently, results from this study improve the surgeon's ability to predict parameters that predisposed to impaired recovery and neurosensory disturbances following SRM3s.

Manual versus rigid intraoperative maxillo-mandibular fixation in the surgical management of mandibular fractures: A European prospective analysis.

PURPOSE: Intraoperative stabilisation of bony fragments with maxillo-mandibular fixation (MMF) is an essential step in the surgical treatment of mandibular fractures that are treated with open reduction and internal fixation (ORIF). The MMF can be performed with or without wire-based methods, rigid or manual MMF, respectively. The aim of this study was to compare the use of manual versus rigid MMF, in terms of occlusal outcomes and infective complications. MATERIALS AND METHODS: This multi-centric prospective study involved 12 European maxillofacial centres and included adult patients (age ≥16 years) with mandibular fractures treated with ORIF. The following data were collected: age, gender, pre-trauma dental status (dentate or partially dentate), cause of injury, fracture site, associated facial fractures, surgical approach, modality of intraoperative MMF (manual or rigid), outcome (minor/major malocclusions and infective complications) and revision surgeries. The main outcome was malocclusion at 6 weeks after surgery. RESULTS: Between May 1, 2021 and April 30, 2022, 319 patients-257 males and 62 females (median age, 28 years)-with mandibular fractures (185 single, 116 double and 18 triple fractures) were hospitalised and treated with ORIF. Intraoperative MMF was performed manually on 112 (35%) patients and with rigid MMF on 207 (65%) patients. The study variables did not differ significantly between the two groups, except for age. Minor occlusion disturbances were observed in 4 (3.6%) patients in the manual MMF group and in 10 (4.8%) patients in the rigid MMF group (p > .05). In the rigid MMF group, only one case of major malocclusion required a revision surgery. Infective complications involved 3.6% and 5.8% of patients in the manual and rigid MMF group, respectively (p > .05). CONCLUSION: Intraoperative MMF was performed manually in nearly one third of the patients, with wide variability among the centres and no difference observed in terms of number, site and displacement of fractures. No significant difference was found in terms of postoperative malocclusion among patients treated with manual or rigid MMF. This suggests that both techniques were equally effective in providing intraoperative MMF.

European multicenter prospective analysis of the use of maxillomandibular fixation for mandibular fractures treated with open reduction and internal fixation.

INTRODUCTION: The goal of mandibular fracture treatment is to restore static and dynamic occlusal functions. Open reduction and internal fixation (ORIF) of these fractures can be associated with an intraoperative and/or postoperative maxillo-mandibular fixation (MMF). The aim of this study was to analyse the use of perioperative MMF and its effects on occlusal outcomes in the management of mandibular fractures. MATERIAL AND METHODS: This multicentric prospective study included adult patients with mandibular fractures treated with ORIF. The following data were collected: age, gender, pre-trauma dental status (dentate, partially dentate), cause of injury, fracture site, associated facial fractures, surgical approach, type of ORIF (rigid, non-rigid or mixed), thickness and number of plates, modality of intraoperative MMF (arch bars, self-tapping and self-drilling screws [STSDSs], manual, other) and duration of postoperative MMF. The primary outcome was malocclusion at 6 weeks and 3 months. Statistical analyses were performed with Fisher's exact test or chi-square test, as appropriate. RESULTS: Between 1 May 2021 and 30 April 2022, 336 patients, 264 males and 72 females (median age, 28 years) with mandibular fractures (194 single, 124 double and 18 triple fractures) were hospitalized. Intraoperative MMF was performed in all patients. Osteosynthesis was rigid in 75% of single fractures, and rigid or mixed in 85% and 100% of double and triple fractures, respectively. Excluding patients who underwent manual reduction, postoperative MMF (median duration, 3 weeks) was performed in 140 (64%) patients, without differences by type or number of fractures (p > 0.05). No significant difference was found in the incidence of malocclusion in patients with postoperative MMF (5%, 95% confidence interval [CI], 2-10%) compared to those without (4%; 95% IC, 1-11%) (p > 0.05). CONCLUSION: Postoperative MMF was performed in more than half of the patients despite adequate fracture osteosynthesis, with wide variability amongst centers. No evidence of a reduction in the incidence of postoperative malocclusion in patients treated with postoperative MMF was found.

The epidemiology and management of odontomas: a European multicenter study.

INTRODUCTION: Odontoma is the most commonly diagnosed odontogenic tumor of the oral cavity. The objective of the present study was to assess the demographic variables, patterns, diagnostic features, and management issues of odontomas treated at several European departments of maxillofacial and oral surgery. MATERIALS AND METHODS: This study was conducted at 8 European departments of oral surgery between January 1, 2004, and December 31, 2018. Only patients with odontomas were included. The following data were recorded for each patient: gender, age, comorbidities, site, size of odontomas, radiographic features, type of odontoma, treatment of odontomas, treatment of associated teeth, complications, and recurrence. RESULTS: A total of 127 patients (70 male and 57 female patients) with odontomas were included. The mean age was 22 years; 71 odontomas were found in the mandible, whereas 56 in the maxilla. In the mandible, the most frequently involved subsite was the parasymphysis, while in the maxilla, the most common subsite was the upper incisor region. The mean size of included odontomas was 15.3 mm. On the whole, 62 complex odontomas, 50 compound odontomas, and 15 mixed-type odontomas were observed. Complete excision of the odontomas was performed in 121 patients. In 24 patients, the extraction of deciduous teeth was performed, and in 43 patients, one or more permanent teeth were removed. Finally, in 9 patients, a partial excision of the odontoma was performed. Recurrence was observed in 4 cases out of 127 patients. CONCLUSIONS: Dental practitioners should be aware of the distinct clinical and radiographic features of odontoma in order to perform an appropriate and early diagnosis. Conventional radiography, such as panoramic radiograph, is often sufficient technique for a diagnosis after clinical suspicion or for an incidental diagnosis to prevent later complications, such as impaction or failure of eruption of teeth.

The epidemiology and management of odontogenic keratocysts (OKCs): A European multicenter study.

The objective of the present study was to assess the epidemiology including demographic variables, diagnostic features, and the management of odontogenic keratocyst (OKCs) at several European departments of maxillofacial and oral surgery. This study is based on a systematic computer-assisted database that allowed the recording of data from treated OKCs. The following data were recorded for each patient: gender, age, voluptuary habits, comorbidities, site, size, radiographic features, treatment of OKCs, length of hospital stay, complications, recurrence, management and complications of eventual recurrence. A total of 405 patients, 249 male and 156 female, with 415 OKCs (407 sporadic and 8 syndromic lesions) were included in the study: 320 lesions were found in the mandible, whereas 95 were found in the maxilla. In the mandible, the most frequently involved subsite was the angle, whereas in the maxilla it was the molar region. The most frequently performed treatment option was enucleation plus curettage/peripheral ostectomy in 204 OKCs (recurrence rate, 9%). Decompression without residual cystectomy (recurrence rate, 66%), marsupialization with residual enucleation with the use of Carnoy's solution (recurrence rate, 50%), decompression with residual cystectomy (recurrence rate, 43%), and simple enucleation (recurrence rate, 24%) were the treatment options with the highest recurrence rates. An appropriate management of odontogenic keratocysts should be individualized, taking into consideration clinical and radiological findings, as well as patients' age and comorbidities.

Imaging of odontogenic keratocysts: a pictorial review.

INTRODUCTION: The aim of the present article was to review and depict the main radiological features of odontogenic keratocysts (OKCs), thus helping the differential diagnoses from other odontogenic cysts and neoplasms. EVIDENCE ACQUISITION: A review of articles published between January 2000 and October 2020 using Medline and the MeSH Term "odontogenic keratocyst" in combination with the following terms "imaging," "radiology," "panoramic radiograph," and "computed tomography," was performed. EVIDENCE SYNTHESIS: Radiographically, OKCs are well-defined unilocular or multilocular radiolucencies bounded by corticated margins. Most lesions are unilocular; instead, multilocular OKCs represent about the 30% of cases, mainly involving the posterior mandible. When, particularly in large lesions, OKCs display a multilocular presentation with adjacent satellite cysts (daughter cysts) a "soap-bubble appearance" can be recognized. DISCUSSION: Panoramic radiograph and CT still play an important role in the diagnosis and treatment planning of OKCs. Unfortunately, it may not be easy to differentiate OKCs from other odontogenic lesions, especially when they are small and unilocular. CONCLUSIONS: Histopathological findings are still necessary to obtain a definitive diagnosis.

Quality of life following maxillofacial trauma in the elderly: a multicenter, prospective study.

BACKGROUND/AIMS: When facial trauma involves elderly patients, the possible presence of frailty and comorbidities in victims of trauma may worsen the posttraumatic symptoms and decrease quality of life. The aim of this multicenter study was to assess the quality of life following surgical or non-operative management of maxillofacial trauma in elderly patients. MATERIALS AND METHODS: This cohort study was based on the administration of validated self-administered questionnaires to all the geriatric patients (70 years or more) with facial fractures from the involved maxillofacial surgical units across Europe, since 1st January 2019 to 31st June 2019. The following questionnaires were administered: SF36 questionnaire; the VFQ-25 questionnaire; the Oral Health Impact Profile - 14 (OHIP14). Outcome variables were VFQ-25 and OHIP-14 results. RESULTS: A total of 37 patients (14 male and 23 female patients) met the inclusion criteria and were included in the study. Elderly patients had an improvement in almost all the categories examined by the SF-36 questionnaire 6 months after trauma, with the only exception of a worsening as for role limitations due to physical health. An improvement was observed in almost all the categories at SF-36 test. A worsening of scores of OHIP-14 for all the considered dimensions in the whole study population was observed too. CONCLUSIONS: Elderly patients following facial trauma experience significant emotional, social, and functional disturbances. We observed that emotional problems, energy/fatigue, social functioning, and generally social limitations played a great role in the decrease of QoL in elderly patients following maxillofacial trauma.

The epidemiology and management of ameloblastomas: A European multicenter study.

The present study aimed at assessing the epidemiology including demographic variables, diagnostic features, and management of ameloblastomas at several European departments of maxillofacial and oral surgery. The following data were recorded for each patient: gender, age, voluptuary habits, comorbidities, site, size, radiographic features, type, histopathological features, kind of treatment, length of hospital stay, complications, recurrence, management and complications of the recurrence. A total of 244 patients, 134 males and 110 females with ameloblastomas were included in the study. Mean age was 47.4 years. In all, 81% of lesions were found in the mandible, whereas 19% were found in the maxilla. Mean size of included ameloblastomas was 38.9 mm. The most frequently performed treatment option was enucleation plus curettage/peripheral ostectomy in 94 ameloblastomas, followed by segmental resection (60 patients), simple enucleation (46 patients), and marginal resection (40 patients). A recurrence (with a mean follow up of 5 years) was observed in 47 cases out of 244 ameloblastomas (19.3%). Segmental resection was associated with a low risk of recurrence (p = 0003), whereas enucleation plus curettage/peripheral ostectomy was associated with a high risk of recurrence (p = 0002). A multilocular radiographic appearance was associated with a high risk of recurrence (p < .05), as well as the benign solid/multicystic histologic type (p < .05). Within the limitations of the study it seems that the management of ameloblastomas will probably remain controversial even in the future. Balancing low surgical morbidity with a low recurrence rate is a difficult aim to reach.

Surgical Management of Mandibular Angle Fractures: Does the Extraction of the Third Molar Lead to a Change in the Fixation Pattern? A European Multicenter Survey.

PURPOSE: The authors conducted a retrospective, multicenter study to investigate the differences in the fixation patterns, in terms of number and thickness of plates, between patients in whom a third molar (3M) was maintained or removed in the line of mandibular angle fractures. MATERIALS AND METHODS: The study was conducted in 6 European level I and II maxillofacial trauma centers. Data were collected on patients ≥ 16 years of age who underwent open reduction internal fixation (ORIF) for mandibular angle fractures (MAF) from 2008 to 2018, in whom a 3M in the fracture line was present and who had a follow-up duration of 6 months. The study population was divided into 2 groups: patients treated with ORIF in whom the 3M was maintained (group 1) and those treated with ORIF in whom the 3M was extracted (group 2) during treatment. The 2 groups were compared for differences in the internal fixation pattern, specifically in terms of the number and thickness of the plates. RESULTS: A total of 749 patients with 774 MAF were collected. A total of 1,050 plates were placed: 849 were ≤ 1.4 mm thick (80.9%) and 201 plates ≥ 1.5 mm thick (19.1%). 548 patients were treated with ORIF and 3M maintained (group 1), and 201 treated with ORIF and 3M extracted (group 2). Statistically significant differences were seen in the number of ≤1.4 mm plates between the 2 groups for single undisplaced/displaced MAF(P value ≤ 0.5) and for undisplaced/displaced angle + parasymphysis/body fractures (P-value ≤ 0.5). CONCLUSIONS: Analyses of data collected from 6 European maxillofacial centers indicated that the majority of surgeons of our sample perceived the MAF as being more unstable when removing the 3M during ORIF leading them to perform a rigid fixation in the angular region.

Management of maxillofacial trauma in the elderly: A European multicenter study.

BACKGROUND/AIMS: Management of maxillofacial trauma in the geriatric population poses a great challenge due to anatomical variations and medical comorbidities. The aim of this study was to analyze the management variables, timing, and outcomes of facial fractures in elderly patients (aged 70 years or more) at several European departments of oral and maxillofacial surgery. MATERIALS AND METHODS: This study was based on a systematic computer-assisted database that allowed the recording of data from all geriatric patients with facial fractures from the involved maxillofacial surgical units across Europe between 2013 and 2017. RESULTS: A total of 1334 patients were included in the study: 665 patients underwent closed or open surgical treatment. A significant association (P < .005) was found between the presence of concomitant injuries and a prolonged time between hospital admission and treatment. The absence of indications to treatment was associated with comorbidities and an older age (P < .000005). CONCLUSIONS: Elderly patients require specific attention and multidisciplinary collaboration in the diagnosis and sequencing of trauma treatment. A prudent attitude may be kept in selected cases, especially when severe comorbidities are associated and function is not impaired.

Surgical management of unilateral body fractures of the edentulous atrophic mandible.

INTRODUCTION: Management of body fractures in patients with edentulous atrophic mandibles represents a challenging task due to patient's age, medical comorbidities, poor bone quality, and vascularity, as well as reduced contact area between the fracture ends. The aim of the study was to assess the demographic and clinical variables, the surgical technique, and outcomes of unilateral body fractures of the edentulous atrophic mandible managed at several European departments of oral and maxillofacial surgery. METHODS: This study is based on a systematic computer-assisted database that allowed the recording of data of all patients with fractures of the atrophic edentulous mandible from the involved maxillofacial surgical units across Europe between 2008 and 2017. The following data were recorded for each patient: gender, age, comorbidities, etiology, synchronous body injuries, degree of atrophy of the mandible according to Luhr classification, type of surgical approach and fixation, length of hospitalization, and presence and type of complications. RESULTS: A total of 43 patients were included in the study: 17 patients' mandibles were classified as class I according to Luhr, 15 as class II, and 11 as class III. All patients underwent open reduction and internal fixation by extraoral approach in 25 patients, intraoral in 15 patients, and mixed in 3 patients. A single 2.0 miniplate was used in 16 patients, followed by a single 2.4 reconstruction plate in 13 patients, by two 2.0 miniplates, and three 2.0 miniplates. Outcome was considered to be satisfying in 30 patients, with no complications. Complications were observed in 13 cases. CONCLUSIONS: Treatment of unilateral body fractures of the edentulous mandible must still be based on the type of fracture, degree of atrophy, experience of the surgeon, and patients' preference. An adequate stability can be obtained by different plating techniques that have to be appropriately tailored to every single specific patient.

The epidemiology of edentulous atrophic mandibular fractures in Europe.

INTRODUCTION: The objective of the present study was to assess the demographic variables, causes, and patterns of edentulous atrophic fractures of the mandible managed at several European departments of oral and maxillofacial surgery. The results of this multicenter collaboration over a 10-year period are presented. METHODS: The data of all patients with fractures of the atrophic edentulous mandible from the involved maxillofacial surgical units across Europe between January 1, 2008, and December 31, 2017 were recorded: gender; age; voluptuary habits; comorbidities; etiology; fracture sites; synchronous body injuries; atrophy of the mandible according to Luhr classification; eventual type of treatment; timing of the eventual surgery; length of hospital stay. RESULTS: A total of 197 patients (86 male and 111 female patients) with 285 mandibular fractures were included in the study. Mean age of the study population was 75 years. Statistically significant associations were found between Luhr classes I - II and condylar fractures on one hand (p < .0005), and between Luhr class III and body and parasymphyseal fractures on the other hand (p < .05). Finally, 135 patients underwent open reduction and internal fixation, 56 patients did not undergo any intervention, and 6 patients underwent closed reduction. No statistically significant association was observed between treatment, timing of treatment, comorbidities, and concomitant injuries. CONCLUSIONS: The management of edentulous atrophic mandibular fractures remains challenging. Treatment decisions should continue to be based on the clinician's previous experience and on the degree of bone resorption in edentulous mandible in relation to fracture subsites.

Motor vehicle accidents-related maxillofacial injuries: a multicentre and prospective study.

OBJECTIVES: The purpose of this European multicenter prospective study was to obtain more precise information about the demographic characteristics and etiologic/epidemiologic patterns of motor vehicle accidents (MVA)-related maxillofacial fractures. STUDY DESIGN: Of the 3260 patients with maxillofacial fractures admitted within the study period, 326 traumas were caused by MVAs with a male/female ratio of 2.2:1. RESULTS: The maximum incidence was found in Zagreb (Croatia) (18%) and the minimum in Bergen (Norway) (0%). The most frequent mechanisms were car accidents, with 177 cases, followed by motorcycle accidents. The most frequently observed fracture involved the mandible, with 199 fractures, followed by maxillo-zygomatic-orbital (MZO) fractures. CONCLUSIONS: In all the 3 groups (car, motorcycle, and pedestrian), mandibular and MZO fractures were the 2 most frequently observed fractures, with some variations. The importance of analyzing MVA-related facial injuries and their features and characteristics should be stressed.

The "European Mandibular Angle" research project: the analysis of complications after unilateral angle fractures.

OBJECTIVE: The aim of this study was to analyze the complications and outcomes of surgical treatment of angle fractures managed at departments of maxillofacial surgery in several European countries. STUDY DESIGN: Patients hospitalized with unilateral isolated angle fractures between 2013 and 2017 were included. The following data were recorded: gender and age of patients, fracture etiology, presence of the third molar, maxillomandibular fixation, osteosynthesis technique, and complications. RESULTS: In total, 489 patients were included in the study. The Champy technique was found to be the most frequently chosen osteosynthesis technique. Sixty complications were observed, at a rate of 12.3%. Complications were associated with the absence of third molars (P < .05). Instead, the Champy technique was associated with fewer complications (P < .05), in comparison with the other adopted techniques. CONCLUSIONS: The management of angle fractures still represents a challenging task with a significant complication rate. The Champy technique still seems to be a valid option for the treatment of such injuries.

The "European zygomatic fracture" research project: The epidemiological results from a multicenter European collaboration.

PURPOSE: Fractures of the zygomaticomaxillary complex (ZMC) are common injuries that may lead to loss of an aesthetically pleasing appearance and functional impairment. The aim of this study was to analyze the demographics, causes, characteristics, and outcomes of zygomatic fractures managed at several European departments of oral and maxillofacial surgery. MATERIALS AND METHODS: This study is based on a multicenter systematic database that allowed the recording of all patients with ZMC fractures between 1 January 2013 and 31 December 2017. The following data were recorded: gender, age, personal medical history, etiology, side of zygomatic fracture, classification of ZMC fracture, associated maxillofacial fractures, symptoms at diagnosis, type of performed treatment, and sequelae/complications. RESULTS: A total of 1406 patients (1172 males, 234 females) were included in the study. Statistically significant correlations were found between assault-related ZMC fractures and the A3 class (p < .0000005) and between Infraorbital Nerve (ION) anesthesia and B class (p < .00000005). CONCLUSION: The most frequent cause of ZMC fractures was assault, followed by falls. The most frequently involved decade of age was between 20 and 29 years. The decision and type of surgical treatment of ZMC fractures depends on several issues that need to be considered on a case by case basis.

The "European Mandibular Angle" Research Project: The Epidemiologic Results From a Multicenter European Collaboration.

PURPOSE: The aim of this study was to analyze the demographic variables and causes and characteristics of mandibular angle fractures managed at several European departments of maxillofacial surgery. MATERIALS AND METHODS: This study was based on a multicenter systematic database that allowed the recording of data from all patients with mandibular angle fractures between January 1, 2013, and December 31, 2017. The following data were recorded: gender, age, etiology, side of angle fracture, associated mandibular fractures, presence of third molar, intermaxillary fixation, and osteosynthesis. RESULTS: The study included 1,162 patients (1,045 male and 117 female patients). A significant association was found between the presence of a third molar and the diagnosis of an isolated angle fracture (P < .0000005). Furthermore, assaults were associated with the presence of voluptuary habits (P < .00005), a younger mean age (P < .00000005), male gender (P < .00000005), and left-sided angle fractures (P < .00000005). CONCLUSIONS: Assaults and falls actually represent the most frequent causes of angle fractures. The presence of a third molar may let the force completely disperse during the determination of the angle fracture, finding a point of weakness.

Assessment of Stability of Craniofacial Implants by Resonant Frequency Analysis.

Implant stability is a principal precondition for the success of implant therapy. Extraoral implants (EO) are mainly used for anchoring of maxillofacial epithesis. However, assessment of implant stability is mostly based on principles derived from oral implants. The aim of this study was to investigate clinical stability of EO craniofacial disk implants (single, double, and triple) by resonance frequency analysis at different stages of the bone's healing. Twenty patients with orbital (11), nasal (5), and auricular (4) defects with 50 EO implants placed for epithesis anchorage were included. Implant stability was measured 3 times; after implant placement, at 3 months and at least after 6 months. A significant increase in implant stability values was noted between all of the measurements, except for triple-disk implants between third and sixth months, and screw implants between 0 and third months. Disk implants showed lower implant stability quotient (ISQ) values compared with screw implants. Triple-disk implants showed better stability compared with single and double-disk implants. Based on resonance frequency analysis values, disk implants could be safely loaded when their ISQ values are 38 (single disks), 47 (double disks), and 48 (triple disks). According to resonance frequency analysis, disk implant stability increased over time, which showed good osseointegration and increasing mineralization. Although EO screw implants showed higher ISQ values than disk implants, disk-type implants can be safely loaded even if lower values of stability are measured.

High frequency of p16 and p14 promoter hypermethylation and marked telomere instability in salivary gland tumors.

OBJECTIVES: to investigate p16(INK4a) and p14(ARF) tumor suppressor gene methylation status, determine telomere length and assess the importance of these epigenetic and genetic parameters in the development of pleomorphic adenoma and carcinoma ex pleomorphic adenoma of the parotid salivary glands. MATERIALS AND METHODS: Genomic DNA from paraffin-embedded samples of 50 pleomorphic adenomas and 10 carcinomas ex pleomorphic adenoma was subjected to methylation specific polymerase chain reaction for hypermethylation analyses and real time polymerase chain reaction for the relative telomere length calculations. RESULTS: Promoter hypermethylation of the two genes was a very frequent event in both neoplasms - between 60% and 90% of samples were hypermethylated - but without significant difference between the groups. The mean relative telomere length in the pleomorphic adenoma group was significantly increased in comparison to the control group (P=0.00), and significantly decreased in comparison to the carcinoma group (P=0.05). Telomeres were also longer in myxoid and cellular histological subtypes of adenomas than in the classic type (P=0.044 and P=0.018, respectively). Longer telomeres were more frequent in tumors with hypermethylated p14(ARF) alleles (P=0.013). CONCLUSION: Promoter hypermethylations seems to be an important mechanism of p16(INK4a) and p14(ARF) inactivation in parotid gland tumors. Telomeric lengthening appears to be involved in the pathogenesis of both benign and malignant tumors of the parotid glands.