Immediate rehabilitation of severely atrophic maxillae using conventional and extended length subcrestal angulated (ELSA) implants: A retrospective analysis of 187 implants in 33 patients with up to three years of function.

PURPOSE: The purpose of this study was to evaluate and determine clinical outcomes and survival rates of straight and extended length subcrestal angulated (ELSA) implants (20-24 mm lengths) placed for immediate (up to 72 h post-operative) or delayed rehabilitation (4 months post-operative) of severely atrophic maxillae. Prosthetic treatment consisted of interim and definitive implant-supported fixed implant-supported prostheses with up to 3 years of function. MATERIALS AND METHODS: A retrospective analysis was conducted of 38 patients (five dropped out; final total was 33), treated between 2017 and 2019 in a private practice. Extended length subcrestal angulated (ELSA) implants and conventional endosseous straight implants (Southern Implants, Irene, South Africa) with (fixed) full arch prostheses were used to restore patients with edentulous maxillae immediately (within 72 hs) or delayed (4 months).  ELSA implants have subcrestal angulations of 24° and 36° of the restorative platforms, external hexagon crestal anti-rotation abutment connections, and lengths between 18 and 26 mm. Implant loading was determined by implant insertion torque values (as determined on the surgical units); 120 Ncm was the threshold level for immediate loading. Clinical and radiographic examinations were done that recorded the clinical outcomes of implants and prostheses. SPSS was used to process the data. RESULTS: Thirty-three patients and 187 implants were included with follow-up periods of at least 12 months (range 12-36 months). The mean age of the study population was 62.6 ± 8.4 years old (at the time of implant placement). Thirty-three patients (86.8%) were followed for 12 months; 13 patients (39.4%) were followed for 24-35 months; 9 patients (27.3%) were followed for 36 months. In total, 13 implants in six patients failed secondary to sinus infections. Mean bone levels (MBLs) were respectively: 0.88 ± 2.12 mm at loading, -1.53 ± 2.03 mm at 12 months, -2.26 ± 1.45 mm at 24 months, and -2.54 ± 1.46 mm at 36 months. The ELSA implants showed significantly lower (p = 0.014) MBL at 36 months than did the conventional implants. One hundred thirty-seven implants were placed and loaded within 72 h; 50 implants were placed and loaded 4 months post placement. The combined implant survival rates were 93.0% at 12 months, 91.1% at 24 months, and 100% at 36 months. The ELSA implants showed significantly lower (p = 0.014) MBLs at 36 months when compared to the conventional implants. CONCLUSIONS: The results of this retrospective clinical chart review indicated that the use of ELSA implants placed into anterior maxillae and nasal crests with accentuated distal tilts (>30°) and simultaneous sinus augmentation provided favorable outcomes for prosthetic rehabilitation in patients with severe atrophic maxillae. ELSA implants placed with simultaneous sinus augmentation are an alternative option to zygomatic implants (ZI) when immediate loading is prescribed. Sinus infections were thought to be the proximate causes of all implant failures. Further long-term clinical studies are warranted with larger patient populations.

Comparison of stress distribution around all-on-four implants of different angulations and zygoma implants: a 7-model finite element analysis.

BACKGROUND: In recent years, zygomatic implants and the all-on-four treatment concept have been increasingly preferred for rehabilitation of atrophic maxillae. However, debate continues regarding the optimal configuration and angulation of the implants. The aim of this study was to analyze the biomechanical stress in implants and peri-implant bone in an edentulous maxilla with zygomatic implants and the all-on-four concept, using multiple implant configurations. METHODS: A total of 7 models consisting different combinations of 4-tilted dental implants and zygomatic implants were included in the study. In each model, a total of 200 N perpendicular to the posterior teeth and 50 N with 45° to the lateral tooth were applied. A finite element analysis was performed for determination of stress distribution on implants and peri-implant bone for each model. RESULTS: Higher stress values were observed in both cortical and trabecular bone around the 45°-tilted posterior implants in all-on-four models when compared to zygomatic implants. In cortical bone, the highest stress was established in an all-on-four model including 45°-tilted posterior implant with 4,346 megapascal (MPa), while the lowest stress was determined in the model including anterior dental implant combined with zygomatic implants with 0.817 MPa. In trabecular bone, the highest stress was determined in an all-on-four model including 30°-tilted posterior implant with 0.872 MPa while the lowest stress was observed in quad-zygoma model with 0.119 MPa. Regarding von Mises values, the highest stress among anterior implants was observed in an all-on-four model including 17° buccally tilted anterior implant with 38.141 MPa, while the lowest was in the including anterior dental implant combined with zygomatic implants with 20,446 MPa. Among posterior implants, the highest von Mises value was observed in the all-on-four model including 30°-tilted posterior implant with 97.002 MPa and the lowest stress was in quad zygoma model with 35.802 MPa. CONCLUSIONS: Within the limits of the present study, the use of zygoma implants may provide benefit in decreasing biomechanical stress around both dental and zygoma implants. Regarding the all-on-four concept, a 17° buccal angulation of anterior implants may not cause a significant stress increase while tilting the posterior implant from 30° to 45° may cause an increase in the stress around these implants.

Indications for zygomatic implants: a systematic review.

PURPOSE: The purpose of this systematic review was to assess the evidence regarding the indications for placement of zygomatic implants to rehabilitate edentulous maxillae. MATERIAL AND METHODS: A focused question using the PIO format was developed, questioning "in patients in need of an implant-supported rehabilitation of the edentulous maxillae, what are the indications for the use of zygomatic implants''. The primary information analyzed and collected was a clear description of the indication for the use of zygomatic implants. RESULTS: A total of 1266 records were identified through database searching. The full-text review was conducted for 117 papers, and 10 were selected to be included in this review. Zygomatic implant indications were extreme bone atrophy or deficiency secondary to different factors. The quad zygoma concept (two zygomatic implants bilaterally placed and splinted) was applied to 107 patients, the classic zygoma concept (one zygomatic implant bilaterally placed and splinted to standard anterior implants) was used in 88 patients, and the unilateral concept (one zygomatic implant on one side, splinted with one or more conventional implants) was employed in 14 patients. CONCLUSIONS: The main indication for the use of zygomatic implants was considered extreme maxillary bone atrophy, resulting from many factors. The clear definition of what was considered "extreme bone atrophy" is not uniquely defined in each paper. Further studies are needed to develop clear indications for zygomatic implants.

Jaw morphology and function in Drilonereis cf. filum (Oenonidae, Annelida).

Representatives of the extant family Oenonidae (Annelida, Eunicida) have a prionognath jaw apparatus, with maxillae having forceps-like elements, a number of asymmetrical dentate plates and long slender carriers, which is characteristic of some fossil forms known from the Paleozoic epoch. Therefore, data on the fine structure and functional morphology of Oenonidae jaws are helpful for the interpretation of fossil materials. The fine structure of the jaw apparatus and the ventral pharyngeal organ is studied in one species of the Oenonidae (Annelida)-Drilonereis cf. filum. The material was collected in the soft bottom of Marseille Bay (Mediterranean) and examined with the help of TEM and histological techniques. A three-dimensional (3D) reconstruction was made from a complete series of semithin sections. The entire jaw apparatus is about 500 µm in length; it includes ventral mandibles and four pairs of maxillae, connected with long paired dorsal carriers and an unpaired ventral carrier. While retracted, it reaches the VIII-XI chaetigers. The most solid part of the maxillary apparatus, that is, maxillae I and II, are 2.5-5 µm thick. The plate consists of a monolithic array of merged scleroprotein granules in which perforations, that is, spaces remaining from microvilli, are visible; the basal part of the maxillary plate is a layer of loosely arranged collagen fibers penetrated with microvilli and has no signs of sclerotization. A study of the jaws of Drilonereis cf. filum showed the presence of common jaw patterns in Eunicida order. Like the jaws of Dorvilleidae, Eunicidae, Onuphidae, and Lumbrineridae, the jaws of Drilonereis are formed at the basis of a typical annelid cuticle's transformation with epi- and basicuticular layers, and its impregnation by merging scleroprotein granules. Through the nature of sclerotization, the jaws of D. cf. filum are similar to those of Dorvilleidae, Histriobdellidae, and the juvenile jaws of Mooreonuphis stigmatis (Onuphidae). Analysis of the 3D-reconstructions of the D. cf. filum jaw apparatus shows that the MxI of this species, and probably of other Oenonidae with dorsal and ventral carriers, can make grasping motions by fixing the joint of the right and left MxI in the two-door hinge type. In general, the overall structure of the jaw apparatus of D. cf. filum and the mechanics of its work shows greater similarity with that of Dorvilleidae than with the jaw apparatus of extant Labidognatha and Simmetrognatha (Onuphidae, Eunicidae, Lumbrineridae). The need for compactization of the jaw apparatus when moving in dense sediment or in the burrows is probably one of the factors determining its structure.

Recurrent chronic suppurative osteomyelitis in the maxilla of a patient with diabetes mellitus and glucose-6-phosphate dehydrogenase deficiency.

AIMS: To report the case of chronic osteomyelitis of a maxilla in a woman with uncontrolled diabetes mellitus (DM), glucose-6-phosphate dehydrogenase (G6PD) deficiency and mental illness, in an attempt to clarify its pathogenesis and treatment. METHODS AND RESULTS: A case of a woman with moderate G6PD deficiency (Class III) who developed bilateral and asynchronous chronic suppurative osteomyelitis (CSO) of her maxilla with extensive bone sequestra, fistulae and whose management was performed by local surgery for bony sequestra and fistulae removal; closure communication under 4 weeks antibiotic cover. CONCLUSIONS: CSO of the jaw may be a complication of the G6PD deficiency and DM and its severity depends on patient's medical status.

Managing the severely atrophic maxilla: Farewell to zygomatic implants and extensive augmentations?

BACKGROUND: Dental rehabilitation of severe atrophic upper jaws remains challenging. A new generation of subperiosteally placed and rigid multi-vector bone-anchored patient-specific implants proposes an innovative line extension in implant dentistry. This single-center retrospective study focused on treating severely atrophic maxillae using these implants. METHODS: All patients who were treated with a patient-specific implant (IPS Implant® Preprosthetic, KLS-Martin, Tuttlingen, Germany) at Hannover Medical School due to severe atrophy of the maxilla who had no history of malignancy, cleft lip or palate, or trauma were evaluated regarding implant stability and prosthetic restoration, as well as complications. RESULTS: Out of a total of 58 inserted implants, 13 implants in 10 patients, which were placed to treat a severely atrophic upper jaw, were identified. The mean follow-up period was 8.2 months (1-29 months). All implants were clinically stable over the entire period. All patients with an observation period of over 2 months received prosthetics for restoration. Minor complications, screw fractures, infection, and exposure of the framework were observed, but these did not lead to failure. CONCLUSION: This initial follow-up suggests that this new generation of implants represents a valuable treatment alternative, especially for patients with a history of failed dental implant placement. Larger numbers of cases and longer observation periods are required to confirm our findings.

Técnica de All-on-4 como opción terapéutica en la rehabilitación mandibular completa: complicaciones técnicas, biológicas e índice de satisfacción de los pacientes / All-on-4 technique as a therapeutic option in the complete mandibular rehabilitation: technical and biological complications and patient satisfaction index

Introducción: Las rehabilitaciones completas se han visto limitadas por los accidentes anatómicos de los maxilares, por lo que diversas técnicas han surgido durante los años para la colocación de los implantes necesarios. Entre ellas, el concepto de All-On-4 permite la rehabilitación de una arcada completa con cuatro implantes, que serán colocados cerca de estructuras anatómicas en pacientes con reabsorciones óseas severas, evitando así cirugías adicionales. Materiales y métodos: El tipo de estudio fue un estudio observacional descriptivo, retrospectivo y transversal en el que se seleccionaron un total de 12 pacientes: 6 pacientes rehabilitados mediante el protocolo de All-on-four (Grupo 1) y 6 pacientes rehabilitados con una prótesis híbrida sobre seis implantes (Grupo 2). Se analizó: Tipo de tratamiento; Nivel de inflamación gingival; Pérdida ósea marginal; Nivel de satisfacción; Complicaciones biológicas y mecánicas; Sexo; Edad. Resultados: En las variables más importantes, se observó que el índice de sangrado fue ligeramente mayor para el Grupo 1. La pérdida ósea marginal fue mayor para el grupo 2. Los pacientes se sentían a gusto con ambos tratamientos, pero el valor es más alto para el Grupo 1. Conclusiones: El índice de satisfacción global analizado resulta alto en ambos grupos y permite valorar de forma muy positiva las dos planificaciones de tratamiento. No hay relación entre las variables sexo, edad o tipo de tratamiento y el nivel de satisfacción. No se puede determinar una relación entre el tipo de tratamiento y el índice de sangrado o pérdida ósea marginal. (AU)

Introduction: Full-arch rehabilitations are limited by the anatomical structures of the maxillas, so different techniques have been proposed for the placement of implants. The All-On-4 concept allows for full-arch rehabilitation with four implants, which will be placed near anatomical structures in patients with severe bone resorption, avoiding additional surgeries. Material and methods: The study design is an observational, descriptive, retrospective and transversal study, which gathered 12 patients: 6 patients treated with the All-On-4 protocol (Group 1) and 6 patients with a hybrid prostheses supported by 6 implants (Group 2). The variables analyzed were: Treatment type; Bleeding on probing; Marginal bone loss; Grade of satisfaction; Biological complications and mechanical complications; Gender; Age. Results: The most important variables showed that Bleeding on probing was slightly higher for Group 1. Marginal bone loss was higher for Group 2. Patients were all satisfied with both treatment options, but the results were higher for Group 1. Conclusions: The global satisfaction index is high in both groups, which rates both treatment options as very positive. There is no relation between gender, age or treatment option and the level of satisfaction. A correlation cannot be made between the treatment option and marginal bone loss or bleeding on probing. (AU)

Calcifying odontogenic cyst of anterior maxillary: Case report and review.

INTRODUCTION AND IMPORTANCE: Calcifying odontogenic cyst (COC) is a rare lesion of jawbone. It is classified among development cyst in the new WHO classification of tumors of the head and neck in 2017. It is a rare pathology, which is found more in the upper maxillae, with a predominance in women in the second or third decade. The diagnosis is based on the analysis of clinical, radiological and histological features. CASE PRESENTATION: We report the case of a 17-year-old patient referred by his orthodontist following the fortuitous discovery of a mixed radiolucent/radiopaque image in the right jaw ranging from the tooth 11 to the tooth 16, for whom the clinical, radiological examination associated with fine needle aspiration cytology suggested a cystic lesion. CLINICAL DISCUSSION: Management initially consisted of decompression of the lesion and complete enucleation after nine months. Histopathological examination gave the diagnosis of calcifying odontogenic cyst. The follow-up showed favorable evolution.

[Imaging features of osteomyelitis of the jaws with different diagnostic methods. A review]. / Características imagenológicas de la osteomielitis de los maxilares evaluada con diferentes métodos diagnósticos. Una revisión.

Osteomyelitis of the jaws (OM) is an infectious pathology involving the bone marrow. It is due to various etiologies, the main one being odontogenic. The diagnosis of OM is a challenge for dentists, who must rely on clinical and imaging examinations. Panoramic radiography is the most frequently used imaging test, but it has some limitations that have improved with the incorporation of new imaging methods such as computed tomography, cone beam computed tomography, magnetic resonance imaging, and bone scintigraphy with radionuclides. The purpose of this review was to describe the imaging characteristics of OM of the jaws according to the radiological diagnostic methods available in the literature in order to provide radiologisst with greater knowledge and improve reporting in daily practice.

Previsibilidade de reabilitações de maxilas edêntulas com a técnica all-on-four: revisão de literatura / Previsibility of edental jaw rehabilitations with the all-on-four technique: literature review

Objetivo: avaliar a previsibilidade das reabilitações de maxilas edêntulas através da técnica all-on-four, mensurada pelas tensões sobre implantes em estudos laboratoriais e sobrevida de próteses, perda óssea marginal e sucesso dos implantes em estudos clínicos. Revisão de literatura: foi executada uma busca na literatura nas bases de dados Lilacs, SciELO e PubMed/Medline, utilizando termos relacionados ao tema, sem restrição temporal e adaptados para cada base. As buscas foram realizadas por um único examinador no período de setembro a novembro de 2019. Após a leitura crítica dos 21 artigos selecionados, constata-se que existem vários estudos com muitos delineamentos que avaliaram a previsibilidade mensurada de várias formas. Considerações finais: diante das evidências científicas encontradas, a reabilitação de maxilas edêntulas com a técnica all-on-four demonstra ser previsível e estável. Estudos retrospectivos, prospectivos e revisões sistemáticas relatam altos índices de sucesso, baixa perda óssea marginal, embasando o uso da técnica all-on-four na odontologia.(AU)

Objective: to assess the predictability of edentulous maxillary rehabilitation using the all-on-four technique, measured by tensions over implants in laboratory studies and prosthetic survival, marginal bone loss and implant success in clinical studies. Literature Review: A literature search was performed in the Lilacs, SciELO and PubMed/ Medline databases, using terms related to the theme, without time restriction and adapted for each base. The searches were carried out by a single examiner from September to November 2019. After a critical reading of the 21 selected articles, it appears that there are several studies with many designs that evaluated the predictability measured in various ways. Final considerations: In view of the scientific evidence found, the rehabilitation of edentulous jaws with the all-on-four technique proves to be predictable and stable. Retrospective, prospective studies and systematic reviews report high success rates, low marginal bone loss, basing the use of the all-on-four technique in dentistry.(AU)

Comparative accuracy of cone-beam CT and conventional multislice computed tomography for real-time navigation in zygomatic implant surgery.

BACKGROUND: Cone-beam computed tomography (CBCT) and conventional multislice CT (MSCT) are both used in zygomatic implant navigation surgery but the superiority of one technique versus the other remains unclear. PURPOSE: This study compared the accuracy of CBCT and MSCT in zygomatic implant navigation surgery by calculating the deviations of implants. MATERIAL AND METHODS: Patients with severely atrophic maxillae were classified into two groups according to the use of CBCT- or MSCT-guided navigation system. The entry and apical distance deviation, and the angle deviation of zygomatic implants were measured on fused operation images. A linear effect model was used for analysis, with statistical significance set at P < .05. RESULTS: A total of 72 zygomatic implants were inserted as planned in 23 patients. The comparison of deviations in CBCT and MSCT groups showed a mean (± SD) entry deviation of 1.69 ± 0.59 mm vs 2.04 ± 0.78 mm (P = .146), apical deviation of 2 ± 0.68 mm vs 2.55 ± 0.85 (P < .001), and angle deviation of 2.32 ± 1.02° vs 3.23 ± 1.21° (P = .038). CONCLUSION: Real-time zygomatic implant navigation surgery with CBCT may result in higher values for accuracy than MSCT.

Correcting Campylorrhinus Lateralis in a Foal by Bone Distraction: A Case Report.

Campylorrhinus lateralis, also known as "wry nose," is a congenital malformation that mainly affects Thoroughbreds. These horses have a unilateral deviation of the maxillae that may be to one side or the other side, and it causes airway obstruction and dental malocclusion. The choice of treatment is not necessarily operation; however, the treatment of choice, which aims to repair the maxillae deviation, is surgical to improve the horse's respiratory condition and correct the dental occlusion. There are currently no reports describing the first surgical technique for such deformity described by Valdez et al. The present study describes the case of a 2-month-old foal of the Mangalarga Marchador breed that was diagnosed with wry nose. The foal presented with accentuated maxillae deviation to the right side, malocclusion of the incisor teeth, and respiratory noises. After diagnosis and physical examination, the foal was treated by surgical correction of the deviation. To correct the deviation, the bone distraction technique with unilateral osteotomy of the right maxillae and fixation of the external bone distractor was chosen. After 90 days, the bone distractor was removed; consequently, malocclusion of the incisors was greatly improved, and respiratory noises were eliminated.

Prospective, Clinical Pilot Study with Eleven 4-Mm Extra-Short Implants Splinted to Longer Implants for Posterior Maxilla Rehabilitation.

In many clinical situations, rehabilitation with implants in the posterior maxillary region is complicated by limited bone availability. In this context, the use of 4 mm long implants (known as extra-short implants) may be used thanks to the concept of osseointegration enhancement. It has been demonstrated that short implants offer an alternative to the regeneration procedures involved in placing longer implants in areas where bone height is compromised. This prospective pilot study tested a treatment protocol in which 11 extra-short (4 mm) implants were splinted to 11 mesially placed longer (8 mm) implants in the posterior maxillary regions of partially edentulous patients, without using supplementary bone regeneration procedures. Eleven patients were included in this single cohort study. The clinical performance of the extra-short implants was assessed during a two-year follow-up period, obtaining a 100% survival rate and mean bone loss of 0.3 mm. Implant stability measured by resonance frequency analysis (RFA) at the time of placement was 54.9 ± 4.9, increasing to 77.0 ± 2.6 at 24 months. The study demonstrated the gradual consolidation of osseointegration in bone of less-than-ideal quality in the posterior maxillary region. The results obtained show that a partially edentulous maxilla with reduced bone height may be rehabilitated by using an extra-short implant splinted to a mesial implant of 8mm length or longer. Despite the small sample size, this pilot study observed that extra-short implants achieved adequate bone stability and clinical performance after a 24-month follow-up.

Zygomatic implants supported rehabilitations in atrophic maxilla: sinus complications, radiological, periodontal and prosthodontic evaluations: a one year follow up retrospective longitudinal study.

The rehabilitation of maxillary bone atrophy represents one of the main challenges of modern oral implantology. The use of zygomatic implants in the prosthetic rehabilitation of the patient affected by severe maxillary bone atrophy is another therapeutic alternative, not exempt from complications. The present study included 19 patients with edentulous maxillae who were treated between 2013 to 2015 with at least two zygomatic implants at the Department of Maxillofacial Surgery, Verona, Italy. The purpose of this retrospective longitudinal study was to evaluate sinus complications and radiological, periodontal and prosthetic evaluations of zygomatic implants technique in severe atrophic. Implant-prosthetic rehabilitation of the upper jaw edentulous severely atrophic using zygomatic implants represents one safe and repeatable technique. In terms of implant survival from our study showed an implant CRS (common reporting standard) of 98.5% and a prosthetic CRS 100% with a mean follow-up period of 19.2 months (range). Both recorded data are superimposed on major reported studies in literature.

A radiologic evaluation of the incidence and morphology of maxillary sinus septa in Japanese dentate maxillae.

PURPOSE: Evaluation of the inner aspect of the maxillary sinus is important for the success of a sinus lift procedure. The most common surgical complication is perforation of the Schneiderian membrane, which is thought to occur because of the presence of maxillary sinus septa. Therefore, we retrospectively investigated the incidence and morphology of maxillary sinus septa using multiplanar reformatted computed tomographic (CT) images from dentate Japanese patients. METHODS: A total of 276 patients and 552 maxillary sinus segments were evaluated. The maxillary sinus septa were divided into four locations: forefront, anterior, middle, and posterior. The heights of the septa were measured at three sites from the deepest point of the sinus floor: lateral, mid-point, and medial. RESULTS: Sinus septa were identified in 191 of 552 (34.6%) maxillary sinus segments obtained from 111 of 276 (40.2%) patients. One unilateral septum was most commonly detected, and the sinus septa were most often located in the middle of the maxillary sinus. The average height of the identified septa was 8.69 ± 4.68 mm (mean ± standard deviation). CONCLUSION: Multiplanar reformatted CT images can identify maxillary sinus septa in any plane. The height of maxillary sinus septa in the dentate maxillae was higher than detected in previous studies. Appropriate treatment planning using CT images should be considered to prevent surgical complications.

Modal analysis of two different types of fixed implant-supported prostheses embedded in edentulous maxillae.

PURPOSE: Modal analysis has been used to monitor and quantify the vibration of each component of a prosthesis at its natural frequency. An understanding of the vibrational characteristics of a prosthesis can guide selection of the appropriate prosthesis configuration to prevent excessive stress. In this study, modal analysis of fixed implant-supported prostheses with 4 or 6 abutments in edentulous maxillae was performed. METHODS: Sixteen patients underwent maxillary dental implant treatment and received screw-fixed implant-supported prostheses (9 patients received 4-abutment prostheses and 7 patients received 6-abutment prostheses) in edentulous maxillae. An impact hammer was used for excitation of the prostheses, and vibration was detected on every crown of the prostheses. The modal parameters were determined in each subject. Furthermore, the modal shapes were compared at each natural frequency. RESULTS: The median natural frequencies of subjects with 4- and 6-abutment prostheses were 697 and 781Hz, respectively. The mean damping ratios did not differ significantly between 4- (8.2±1.7%) and 6-abutment (6.6±1.7%) prostheses (p=0.125). The mean maximum displacements of fixed prostheses were significantly lower for 6-abutment (10.3±3.3µm) than for 4- (20.3±9.1µm) prostheses (p=0.004). The median number of vectors in antiphase was significantly lower for 6- (4) than for 4-abutment prostheses (14) (p=0.001). CONCLUSIONS: The current study demonstrated less adverse vibration in the 6-abutment prostheses than in the 4-abutment prostheses, suggesting that modal analysis can contribute to novel future developments in the designs of dental implant prostheses.

Morphology of the mandibles and the first maxillae in the family Lithobiidae (Myriapoda, Chilopoda), with remarks on their phylogenetic significance.

The mandibles and the first maxillae of 37 species of the family Lithobiidae (Myriapoda, Chilopoda) were investigated and compared to provide a structural overview and evaluate their significance for the systematics of the family. The species sampling focused on the genus Lithobius, examining 33 species of four subgenera (Lithobius, Monotarsobius, Sigibius, Ezembius), as this genus represents about half of the known diversity of Lithobiidae, including more than 500 assigned species and subspecies. The microstructures on the mandibular gnathal edge and the first maxillary telopodites and coxal projections were studied using scanning electron microscopy. Although having a similar structural pattern, we demonstrate that the microstructures are variable within and between species of adult specimens and commonly show intergradation. To check for intraspecific variability of microstructures and character stability, specimen sampling was extended for the two common Austrian species Lithobius dentatus and Lithobius validus, for which seven specimens depicted no major differences in the mandibular gnathal edge and the first maxillae. Our data suggest the presence of three characters in the mandibular gnathal edge and the first maxillae useful for lithobiid phylogeny. These characters were tested in a phylogenetic analysis together with previously described and novel morphological characters. Subgenera of Lithobius are mostly non-monophyletic, and several other genera of Lithobiinae as well as other subfamilies group with particular species or clades of Lithobius. The results corroborate a close relationship between Disphaerobius loricatus and Lithobius (Ezembius) giganteus, strengthening the hypothesis that Pterygoterginae is nested within Lithobiinae and specifically within Lithobius, allied to L. (Ezembius) and Hessebius.

Revised fish aging techniques improve fish contaminant trend analyses in the face of changing Great Lakes food webs.

Incorporation of fish age into the assessment of status and trends for persistent, bioaccumulative and toxic chemicals in the Great Lakes has become an important step for the U.S. EPA's Great Lakes Fish Monitoring and Surveillance Program (GLFMSP). A slowing in the rate of decline for total PCBs in Lake Huron beginning in 2000, led the Program to complete a retrospective analysis to assess how chemical contamination may be influenced by fish age. Analytical results suggest that fish age is an important variable when assessing contaminant trends and that the Program needed to revise its compositing scheme to group fish according to age, rather than by length, prior to homogenization and chemical analysis. An Interlaboratory comparison study of multiple age structures was performed to identify the most appropriate age estimation structure for the Program. The lake trout (Salvelinus namaycush) maxillae was selected, over the otolith, as the most precise, accurate, and rapidly assessed structure for the Program when compared between laboratories and against the known age from the coded wire tag (CWT). Age-normalization practices can now be implemented when assessing contaminant concentrations and trends for the GLFMSP.

Intraosseous lipoma of the maxillary tuberosity: A case report.

Intraosseous lipoma appears less frequently in the maxilla than in the mandible. The initial phase of tumor development is characterized by asymptomatic growth, followed by the presence of pain and paresthesia in the later stage. We report the case of a 43-year-old female patient who contacted a doctor because of periodic pains and stupor in the left side of the upper jaw. The exostosis-like formation was found by palpation, subsequently raising suspicion of an odontogenic tumor on the basis of panoramic imaging (dental orthopan). The intraosseous lipoma was histopathologically diagnosed after surgical procedure and standardized treatment of removed tumefaction. Clinical features and x-ray findings of the intraosseous lipoma within the maxillary region are generally blurred. Surgery is the recommended treatment, and histopathology analysis is of utmost importance for the final diagnosis.

Functional Morphology of Eunicidan (Polychaeta) Jaws.

Polychaetes exhibit diverse feeding strategies and diets, with some species possessing hardened teeth or jaws of varying complexity. Species in the order Eunicida have complex, rigid, articulated jaws consisting of multiple pairs of maxillae and a pair of mandibles. While all Eunicida possess this general jaw structure, several characteristics of the jaws vary considerably among families. These differences, described for fossilized and extant species' jaws, have been used to infer evolutionary relationships. Little has been done, however, to relate jaw functional morphology and feeding behavior to diet. To explore these relationships, we compared the jaw kinematics and morphology of two distantly related eunicidan taxa with superficially similar jaw structures: Diopatra spp. (Onuphidae), predominantly herbivorous and tube dwelling, and Lumbrineris spp. (Lumbrineridae), a burrowing carnivore. Jaw kinematics were observed by filming individuals biting in a number of orientations. Some differences in jaw structure and kinematics between Diopatra spp. and Lumbrineris spp. can be interpreted to be consistent with their differences in diet. Relating jaw morphology to diet would improve understanding of early annelid communities by linking fossil teeth (scolecodonts) to the ecological roles of extant species with similar morphologies.