Vacuum energy and the fixed point of QED

The vacuum energy of QED, as a function of the coupling constant α, is shown to have an absolute minimum at the critical coupling αc=π/3. The effect of chiral symmetry breaking diminishes as the coupling is increased. We argue that these aspects of the vacuum energy shall remain unaltered beyond the ladder approximation.

Segmental osteotomy for the correction of a malpositioned single implant: an 8-year follow-up

This case report is an 8-year follow-up of a malpositioned single implant, which was treated with segmental osteotomy, to confirm the treatment's characteristics, indications, and advantages. Deep buccal positioning of an endosseous implant placed in the maxillary left central incisor area did not permit acceptable prosthetic rehabilitation, despite its favorable bone insertion with no significant marginal bone loss. The surgical procedure included osteotomy and block movement performed toward the lingual and cervical position, fixed with a provisional prosthesis and miniplates and mini-implants. A connective tissue graft was necessary for esthetics optimization and was performed in a second stage. Advantages including the prevention of alveolar ridge damage, the improvement of gingival contour, and the use of an already integrated implant are presented. Clinically satisfactory hard and soft tissue stability permitted us to consider segmental surgery as a reliable alternative for malpositioned osseointegrated implants.

Correção da deficiência transversa da maxila por meio da expansão rápida da maxila cirurgicamente assistida

Fundamentation: The correction of maxillary transverse deficiencies involves orthodontic and surgical procedures that can be performed before or after skeletal maturity. The surgically assisted rapid maxillary expansion (SAR ME) is performed by osteotomies through the lateral walls of the maxilla, zygomatic and canines buttresses, palatal and pterygomaxillary sutures, causing the maxillary disjunction. Followed by activation of the expander to the desired over-expansion in order to correct intercuspal later. Objective: The purpose of this study was to discuss the issues involved in the diagnosis of maxillary atresia, SAR ME indications, as well as surgical technique, through a case study. Methods: The male patient, 19 years old, had severe transverse maxillary deficiency with facial pattern III , Class III , with great lip incompetence. The patient underwent general anesthesia in a hospital environment, the osteotomies was done according to the technique described by Epker and Wolford (1980). Postoperatively, the patient underwent activations daily for 15 days and after 6 months, the orthodontist installed fixed orthodontic appliance to prepare the patient to orthognathic surgery later. Conclusion: The diagnosis by clinical evaluation and models study is essential for the indication of SAR ME and this procedure provides good predictability in the correction of transverse deficiency, with minimal morbidity.

A utilização de abutment de zircônia na reabilitação oral: aspectos protéticos e periodontais

Zirconia abutments are used to obtain satisfactory aesthetic results in implant fixed anterior prostheses when metal abutments promote a grayish mucosal discoloration of the peri-implant soft tissues. However, there is a lack of studies to confirm the clinical performance of the peri-implant soft tissues surrouding zirconia abutments. This study described a case report of a patient treated with implant fixed all-ceramic crown made out on zirconia abutment after 3 years of followup. A 47-year-old female patient was admitted to the dental clinic (Aracatuba Dental School) complaining about the fracture of her implant fixed single crown in the region of the left lateral incisor. The patient chose the replacement of the fractured prosthesis for an allceramic crown. After 3 years of follow-up it was observed that maintenance of the aesthetic results and the peri-implant soft tissue without any inflammation or gingival recessions. Within the limitations of a case report, it can be conclude that zirconia abutments is a effective rehabilitation treatment because it preserves the aesthetics and function through the maintenance of peri-implant tissues.

Magnet-retained facial prosthesis combined with maxillary obturator

Prosthetic rehabilitation of the midfacial defects has always perplexed prosthodontists. These defects lead to functional and esthetic deficiencies. The purpose of this clinical case report was the presentation of the prosthetic rehabilitation of an extraoral-intraoral defect using two-piece prosthesis magnetically connected. This prosthesis has dramatically improved the patient’s speech, mastication, swallowing, and esthetic.

Solução estética para prótese sobre implante

Próteses sobre implantes esteticamente favoráveis estão diretamente relacionadas com a condição dos tecidos moles e duros que as envolvem. A preservação dos tecidos mucogengivais ao redor de implantes dentários instalados na maxila anterior propicia um sorriso harmonioso, com uma estética bastante agradável. No entanto, em alguns casos, isso não ocorre principalmente pela grande reabsorção tecidual na região, na qual deveria ter sido realizado enxerto ósseo, antes mesmo da instalação dos implantes. Desse modo, o objetivo deste trabalho foi apresentar uma solução reabilitadora estética para essas possíveis falhas durante o planejamento com reabilitações sobre implantes, por meio de gengiva artificial cerâmica.

Prótese total fixa na maxila: soluções protéticas

The modalities of treatment with prostheses over implants for total edentulous patients can be divided in fixed and removable prostheses (overdentures). The fixed prostheses modality has proven to offer better results as to the functional aspects and, results in higher longevity. Overdentures are considered as a modality of rehabilitation utilized to compensate the need for better retention, aside from augmenting chewing efficiency. Its use is justified by its facilitated hygiene, reduced surgical and prosthetic costs, reestablishment of labial support and elimination of the possibility of air escape. However, this option presents psychosocial downside, since the fact that it is considered a removable rehabilitation modality does not please the majority of patients. Although many patients prefer a fixed implant-supported prosthesis to a removable overdenture, frequently it is necessary to utilize an implant retained overdenture as an alternative to the treatment, due to anatomical, physiological, aesthetic, hygienic, and financial limitations regarding the patient. The objective of this study was to discuss a clinical case of a partially edentulous patient treated in the Implantodontic Surgery Post-Graduation Course from the Kenedy Dentistry Institute Mozarteum/Famosp Unit – Goiânia-Brazil), and submitted to osseointegrated implants surgical fixation techniques. A modality of differential diagnosis was established after osseointegration period, it aimed at facilitating the choice of a rehabilitation model that could favor the patient’s and professional`s expectations. Therefore the appreciated aspects were function, comfort, aesthetics, and especially the patient satisfaction.

Marginal deterioration of the silicone for facial prosthesis with pigments after effect of storage period and chemical disinfection

The failure of facial prostheses is caused by limitations in the properties of existing materials, especially flexibility and durability. Therefore, this study evaluated the marginal deterioration of a silicone used for fabrication of facial prostheses (Silastic MDX4-4210, Dow Corning Corporation, Midland, MI, USA) according to the influence of artificial aging, daily disinfection, and 2 types of pigmentation. Thirty specimens were fabricated and subdivided in 6 groups: without pigmentation, pigmented with make-up powder and iron oxide, and evaluated with and without the action of the disinfectant. Analysis of marginal deterioration was performed on a scanning electron microscope (magnification, ×5000) immediately 6 months and 1 year after fabrication of specimens, following the guidelines of ASTM International. After visual analysis of the photomicrographs, it was noticed that all groups presented marginal deterioration and alterations in surface texture with time. The use of disinfection did not contribute to the marginal deterioration of polymer (silicone), regardless of the pigmentation and artificial aging.

Influência do material oclusal na distribuição de tensões em próteses implantossuportadas unitárias

Objective: the aim of this study was to evaluate the influence of occlusal veneering material in single fixed implant-supported crowns through the 3-D finite element method. Material and methods: Four models were fabricated using the Rhinoceros 4.0, SolidWorks, and InVesalius softwares. Each model represented a block of mandibular bone with an external hexagon implant of 5 mm x 10 mm and different veneering materials including NiCr (1), porcelain (2), composite resin (3), and acrylic resin (4). An axial load of 200 N and an oblique load of 100 N were applied. Results: model (2) with porcelain veneering presented a lower stress concentration for the NiCr framework, followed by the composite resin and acrylic resin. The stress distribution to the implant and bone tissue was similar for all models. Conclusions: there is no difference of stress distribution to the implant and supporting structures by varying the veneering material of a single implant-supported prosthesis.

Influência do material oclusal na distribuição de tensões em próteses implantossuportadas unitárias

Objective: the aim of this study was to evaluate the influence of occlusal veneering material in single fixed implant-supported crowns through the 3-D finite element method. Material and methods: Four models were fabricated using the Rhinoceros 4.0, SolidWorks, and InVesalius softwares. Each model represented a block of mandibular bone with an external hexagon implant of 5 mm x 10 mm and different veneering materials including NiCr (1), porcelain (2), composite resin (3), and acrylic resin (4). An axial load of 200 N and an oblique load of 100 N were applied. Results: model (2) with porcelain veneering presented a lower stress concentration for the NiCr framework, followed by the composite resin and acrylic resin. The stress distribution to the implant and bone tissue was similar for all models. Conclusions: there is no difference of stress distribution to the implant and supporting structures by varying the veneering material of a single implant-supported prosthesis.

Diastemas: reestablishment of an attractive smile

A healthy and attractive smile is very valued in today s society. Yet this requires better aesthetic and cosmetic solutions from dental surgeons.The present paper presents a case report of diastema closure using an association of tooth movement induced by orthodontic elastics,dental cosmetics and resin-bonded prosthesis. The female patient L.B.A.J., aged 19 years, visited the Integrated Clinic of Araçatuba DentalSchool UNESP mainly complaining of missing teeth and poor esthetics. After anamnesis, clinical and radiographic examination revealedhypodontia of the maxillary right and left first premolars, abnormal maxillary right lateral incisor shape and diastema between the maxillaryright lateral incisor and canine and between the maxillary left lateral incisor and canine. Planning was done which included indication ofdiastema closure with composite resin restoration and metal-free resin-bonded prosthesis, with a structure made of Vectris (Ivoclar VivadentInc., Amherst, NT, USA). The option for dental cosmetics associated with resin-bonded prosthesis after movement with orthodontic elasticsresulted in an excellent aesthetic outcome of low cost and short treatment duration.Indexing terms: composite resins; diastema; fixed resin bonded partial denture.

Chronic osteomyelitis of the maxilla and mandible: microbiological and clinical aspects

Osteomyelitis of the mandible and maxilla are common in developing countries and their treatment may be long-standing and difficult. Thus, the aim of this study was to discuss the main biological aspects of the chronic osteomyelitis of the jaws of especial interest for dental team. These infections are associated with a complex microbiota composed mainly by anaerobic bacteria, sometimes associated with microorganisms originated from the skin and digestive tract. These data suggest that chronic osteomyelitis of the mandible and maxilla should be treated as anaerobic infections in most cases. In addition, local surgical treatments are relevant in the therapy outcome, associated to the use of antimicrobial agents, and the failure to accomplish them is a major cause of treatment failure.

Reconstruction of maxillary ridge atrophy caused by dentoalveolar trauma, using autogenous block bone graft harvested from chin: a case report

Background Dentoalveolar trauma, especially when involving front teeth, negatively affect the patient’s life; in particular, tooth avulsion is a complex injury that affects multiple tissues, and no treatment option offers stable long-term outcomes. The aim of this study was to report a case of reconstruction of atrophic anterior alveolar ridge after tooth loss, performed with autograft harvested from the chin, and subsequent prosthetic rehabilitation with the use of an osseointegrated implant. Case report A 23-years-old Caucasian girl, presented an atrophic alveolar bone in the area of tooth 11, as a result of tooth resorption 10 years after a tooth reimplantation procedure. Reconstruction was performed with autogenous bone harvested from the chin. After 6-months healing period to allow autograft incorporation, a dental implant was inserted. After further 6- months, a screw-retained implant supported metal-ceramic prosthesis was fabricated. Results The prosthetic rehabilitation was successful, and after a follow-up period of 5 years, the achieved result was stable.Conclusion It can be concluded that the autogenous bone graft harvested from the chin, is a safe and effective option for alveolar ridge defects reconstruction, allowing a subsequent placement of a dental implant supporting a prosthetic restoration.

The use of a bite fork to help mobilize the maxilla after downfracture during the Le Fort I osteotomy: a technical note

Introduction The Le Fort I osteotomy is indicated to reposition the maxilla in the surgical correction of dentofacial deformities. Although it is a known surgical step, like any surgical procedure, it can have complications and difficulties; among these, the initial mobility of the jaw is very common after completing all corticotomies. Methods The authors present a technique in which the bite fork is used as an auxiliary tool in maxilla downfracture, especially in cases of maxillary impaction where vertical space is created on the walls of the corticotomy. Findings As the bite fork acts as a scraper with a long leverage arm, an advantage would be the better distribution of forces along the corticotomy, minimizing the risk of bad fracture and facilitating maxillary downfracture movement.

Estudo retrospectivo de implantes osseointegrados instalados imediatamente após exodontias

Objectives: to evaluate implant survival immediately placed after tooth extraction considering different sites, prosthodontic modalities, and the need for biomaterials. Material and methods: dental records of 500 patients treated with dental implants between 2004 and 2011 were screened. Results: only 200 records (20%) corresponded to immediate implants. Reasons for tooth extraction included extensive caries, bone loss, and root fractures. From the 197 immediate dental implants, 86 were placed in the maxilla with a survival rate of 93.9% and 111 in the mandible (survival rate of 99.1%). The overall survival rate was 97.46%. Prosthodontic modalities identified were: Brånemark classic complete denture screwed prostheses (36%), overdentures (5.6%), fixed partial denture (31%), and single-tooth prostheses (27.4%). Also, it was observed that in 33% of cases there was a need for the use of grafts and/or biomaterials. Conclusion: it can be concluded that, when correctly indicated, immediate implants are an excellent choice. The anterior mandibular region, screwed and overdenture-type prostheses presented higher success rates when associated to immediate implant placement. The need for bone graft/biomaterial does not affect the clinical results.