Abstract

The aim of this study was to compare the 5-year outcome of full-arch mandibular fixed prosthetic rehabilitation using the All-on-4 concept in smoking and nonsmoking patients. This retrospective cohort study included 200 patients (n = 100 smokers, n = 100 nonsmokers), 119 women and 81 men, with an average age of 53.7 years, rehabilitated in immediate function with 800 implants. Implant cumulative survival rate estimation (Kaplan-Meier with log-rank test) and marginal bone resorption (MBR) at 5 years (Mann-Whitney test) were compared between both groups. Multivariable analysis was used to investigate potential risk indicators for MBR ≥ 2.8 mm at 5 years. Nine patients (4.5%) were lost to follow-up. Four patients lost eight implants, specifically one nonsmoking patient (n = 1 implant) and three smoking patients (n = 7 implants), resulting in a cumulative survival rate estimation of 99.0% and 96.9% for nonsmokers and smokers, respectively (P = 0.296). The average (standard deviation) MBR at 5 years was 1.68 mm (0.76 mm) and 1.98 mm (1.02 mm) for nonsmokers and smokers, respectively (P = 0.045). Smoking (odds ratio = 2.92) was the only risk indicator significantly associated with MBR ≥ 2.8 mm in multivariable analysis. Smoking should not be an absolute contraindication for rehabilitation of the edentulous mandible through the All-on-4 concept; however, smoking habits were significantly associated with MBR ≥ 2.8 mm.

Introduction

Smoking has long been causally associated with several cancers, heart disease, and chronic obstructive pulmonary disease and represents the leading cause of premature death and morbidity in the Western world (U.S. Department of Health and Human Services. The health consequences of smoking: a report of the surgeon general. 2004; 1). Cigarette smoking was previously reported to have a detrimental effect on early bone tissue response around dental implants, with marginal bone loss, gaps, and fibrous tissue surrounding the implants retrieved from smokers, together with a significant decrease in bone to implant contact percentage compared to nonsmokers (2).

Purpose. This study sought to assess the clinical outcome and survival rate of oral implants placed in individuals with ectodermal dysplasia (ED), based on previously published studies. Methods. An electronic search without time restrictions was undertaken in 5 databases (PubMed/Medline, Web of Science, ScienceDirect, J-Stage, Lilacs). Descriptive statistics, Kaplan Meier estimator and implant failure probability were calculated. Results. 90 publications were included, reporting 228 ED patients that received 1472 implants (1392 conventional, 47 zygomatic, 33 mini-implants). Mean age of the patients was 20.2±6.8 years (2-56). Patients had a mean of 3.2±2.5 maxillary and 2.1±2.6 mandibular permanent teeth (min-max, 0-14). Patients received a mean of 8.2±3.8 implants (1-20). Most implants were placed in the third decade of life, 24.6% of the implants were placed in children (0-17 years of age). 1391 implants had information on follow-up (72 failures, 5.2%). The 20-year CSR was 84.6%. The probability of failure was 4.5% (95%CI 3.5%-5.6%, p<0.001). Additional treatments performed were Le Fort I (99 implants, 20 patients, 3.5% failed), grafting (497 implants, 77 patients, 5.2% failed), distraction osteogenesis (79 implants, 16 patients, 10.1% failed). Mean follow-up was 42.9±41.9 months (min-max, 2-240). Conclusions. Dental implants placed in ED patients, either infants or adults, present a high survival rate (20-year CSR 84.6%).

INTRODUCTION

Ectodermal dysplasia (ED) encompasses a number of genetic syndromes characterized by a congenital defect in two or more of the ectodermal structures of the body. The condition is estimated to occur in approximately 1 in 100,000 live births, and approximately 132 different hereditary syndromes related to ED have been identified (Clarke, 1987). The syndromes usually affect the hair, teeth, nails, sweat glands, craniofacial structures, digits, and occasionally mesodermal abnormalities (Clarke, 1987). The impact on the oral and maxillofacial region includes decreased growth of the mandible and maxilla, deficient development of the maxillary and mandibular alveolar ridges, significant reduction in salivary secretions, and malformations and anomalies of number and shape of primary and permanent teeth (Martin et al., 2005). As many of these patients present oligodontia (absence of 6 or more teeth) or anodontia (complete absence of teeth), a prosthetic rehabilitation is usually desirable. The degree of dentoalveolar tissue deficiency can make an implant-supported prosthesis an appropriate method of definitive occlusal restoration in these patients. However, as the absence of teeth is congenital, this raises the issue of placement of oral implants in growing children, mainly due to the influence of craniofacial growth on the implant’s behavior (Singer et al., 2012). The aim of the present review was to assess the clinical outcome and survival rate of oral implants used for the oral rehabilitation of ED patients.

In this paper we present the first results of a broad research line aiming a better understanding about dental implants as the number of procedures, successes and failures in Brazil and possible reasons of losses (from problems on diagnose to fabrication defects from different brands offered in the Brazilian market). One thing that is already evident is the lack of details of the performed elemental analysis of implants, not only in Brazil but also on the majority of reported analyses published on international journals dedicated to the field. There are already a significant number of reports about the composition of dental implants and its surfaces, but in general they have not performed tests enough to validate the results nor reported the procedure with sufficient details establishing their comprehensiveness, which is critical to enable a comparison between those results. One detected problem is the using of a non standard geometry in some equipment that require special shapes or dimension for the analysis. The other is the determination of the uncertainties to be associated to the results. Here we will perform a brief review of the dental implant history, of some problems found in the elemental analysis and will present two sets of measurements, one to investigate the consequences of using nonstandard geometries and another comparing elemental analyses made with different instruments.

INTRODUCTION

The first record of dental implants was 2000 BC, with the use of gold, platinum and porcelain. The Mayan civilization, among the many scientific advances it generated, was the first to use endosseous dental implants [1]. Over the years, various materials have been tested for dental implants, such as chromium-cobalt-molybdenum and iron-chromium-nickel alloys, stainless steel, and metals such as gold, platinum and silver. However, the clinical success obtained in the medium and long term for these materials was very low due to high peri-implant bone reabsorption [2]. The finding of the concept of osseointegration only occurred in 1965 by Brånemark in Sweden, leading a research group at the University of Gothenburg [3]. The original research of Brånemark was on the microcirculation of blood in rabbit tibias, with the assistance of a small titanium optical chamber, which was surgically inserted in the bone, to investigate the blood supply. After some time, when he tried to remove the chamber, Brånemark found it impossible because the chamber was integrated to the bone. It was thus evident that the integration between this metal and bone occurred perfectly, and there was no rejection [3]. The concept of osseointegration was then defined as the direct structural and functional connection between ordered, living bone and the surface of a loadcarrying implant. [4] Brånemark’s next step was to apply his discovery to oral rehabilitation, using titanium to built dental implants. Since then it was noticed that the clinical success of the implantology is directly related to the occurrence of the phenomenon of osseointegration and the type of material used [3].

Introduction: Companies selling dental implant guided systems mostly offer similar surgical guides. The purpose of this paper is to present an innovative-guided surgery system which originality lies in its guidance device, and to report the author’s experience in using this system for dental implant surgery. Technical protocol: Two parallel tubes on either side of the drilling axis guide the successive drills and the implant placement. As a result of the lateral guidance, there is no friction of the drills on the surgical guide, which would damage it or contaminate the drilling hole with particles torn out from the guide. No radiological guide is needed during the radiographic examination stage. No successive diameter reduction tubes are requested. This guide can be used for all brands of implants. Discussion: In our experience, 67 implants (31 titanium and 36 zircon implants) were placed in 35 patients with guided surgery system. Multiple clinical cases were treated with this system: ‘onestage’ or a ‘two-stage’ surgical protocol, with flap and flapless surgical techniques, and with delayed or immediate loading. Clinical cases treated revealed good implant placement with planning. The widely open design of this guide allows irrigation and practitioner’s sight control under conditions comparable to those of operations performed without surgical guide. Conclusion: This dental implant guided system appears to be a significant advance in the field of implant surgical guides.

Introduction

The use of guides in implant surgery is constantly increasing. This success is due to the service provided both to trainee practitioners (ensuring their surgical gesture) and to experienced clinicians (for whom guided surgery provides a reliable therapeutic solution in the case of complex implantations in which the accuracy of the implant positioning is crucial and may sometimes avoid pre-implant surgery). Of course, the use of these techniques is also interesting in the implant-supported rehabilitation by immediate ‘loading’. If the characteristics of the ideal guide had to be defined, first of all one would ask for precision: absence of defective manufactur ing, a perfect fit in the mouth, high stability during the operation and optimal drill guide for a perfect reproducibility of the planning. It is also necessary that the guide can be transported, stored and sterilized without any distortion or degradation. In addition, it is desirable that the design of the guide does not interfere with the visual inspection by the surgeon and with the drill irrigation. Finally, the use of this guide should not lead to a high increase in the cost of the operation. Companies selling dental implant guided systems offer surgical guides of similar design: they are dental, mucosa or bone supported, mostly made of resin, whereby drill  holes are prepared within the body of the guide itself. These drill holes usually receive metal sleeves of various diameters to guide successive drills. aving had the opportunity to test this innovative device, which differs significantly from the usual design, the authors wish to describe the system and the surgical protocol and to share their experience in their clinical cases (67 implants).

EEG remains the mainstay test for the diagnosis and treatment of patients with epilepsy. Unfortunately, ambulatory EEG systems are far from ideal for patients who have infrequent seizures. These systems only last up to 3 days and if a seizure is not captured during the recordings, a definite diagnosis of the patient’s condition cannot be given. This work aims to address this need by proposing a subdermal implantable, eight-channel EEG recorder and seizure detector that has two modes of operation: diagnosis and seizure counting. In the diagnosis mode, EEG is continuously recorded until a number of seizures are recorded. In the seizure counting mode, the system uses a low-power algorithm to track the number of seizures a patient has, providing doctors with a reliable count to help determine medication efficacy or other clinical endpoint. An ASIC that implements the EEG recording and seizure detection algorithm was designed and fabricated in a 0.18 μm CMOS process. The ASIC includes eight EEG channels and is designed to minimize the system’s power and size. The result is a power-efficient analog front end that requires 2.75 μW per channel in diagnosis mode and 0.84 μW per channel in seizure counting mode. Both modes have an input referred noise of approximately 1.1 μVrms.