Marc Quirynen

Comparison of surface roughness of oral hard materials to the threshold surface roughness for bacterial plaque retention: A review of the literature

OBJECTIVES The roughness of intraoral hard surfaces can influence bacterial plague retention. The present review evaluates the initial surface roughness of several intraoral hard materials, as well as changes in this surface roughness as a consequence of different treatment modalities. METHODS Articles found through Medline searches were included in this review if they met the following criteria: 1) stated threshold surface roughness values and reputed change in surface roughness due to different manipulation techniques; or 2) included standardized surface conditions that could be compared to the treated surface. RESULTS Recently, some in vivo studies suggested a threshold surface roughness for bacterial retention (Ra = 0.2 micron) below which no further reduction in bacterial accumulation could be expected. An increase in surface roughness above this threshold roughness, however, resulted in a simultaneous increase in plaque accumulation, thereby increasing the risk for both caries and periodontal inflammation. The initial surface roughness of different dental materials (e.g., teeth, abutments, gold, amalgam, acrylic resin, resin composite, glass ionomer or compomer and ceramics) and the effect of different treatment modalities (e.g., polishing, scaling, brushing, condensing, glazing or finishing) on this initial surface roughness were analyzed and compared to the threshold surface roughness of 0.2 micron. The microbiological effects of these treatment modalities, if reported, are also discussed and compared to recent in vivo data. SIGNIFICANCE Based on this review, the range in surface roughness of different intraoral hard surfaces was found to be wide, and the impact of dental treatments on the surface roughness is material-dependent. Some clinical techniques result in a very smooth surface (compressing of composites against matrices), whereas others made the surface rather rough (application of hand instruments on gold). These findings indicated that every dental material needs its own treatment modality in order to obtain and maintain a surface as smooth as possible.

An in vivo Study of the Influence of the Surface Roughness of Implants on the Microbiology of Supra- and Subgingival Plaque

In nine patients with fixed prostheses supported by endosseous titanium implants, 2 titanium abutments (trans-mucosal part of the implant) were replaced by either an unused standard abutment or a roughened titanium abutment. After 3 months of habitual oral hygiene, plaque samples were taken for differential phase-contrast microscopy, DNA probe analysis, and culturing. Supragingivally, rough abutments harbored significantly fewer coccoid micro-organisms (64 us. 81%), which is indicative of a more mature plaque. Subgingivally, the observations depended on the sampling procedure. For plaque collected with paper points, only minor qualitative and quantitative differences between both substrata could be registered. However, when the microbiota adhering to the abutment were considered, rough surfaces harbored 25 times more bacteria, with a slightly lower density of coccoid organisms. The presence and density of periodontal pathogens subgingivally were, however, more related to the patients dental status than to the surface characteristics of the abutments. These results justify the search for optimal surface smoothness for all intra-oral and intra-sulcular hard surfaces for reduction of bacterial colonization and of periodontal pathogens.

A study of 589 consecutive implants supporting complete fixed prostheses. Part II: Prosthetic aspects

In 91 consecutive edentulous patients, 103 jaws were treated with complete fixed prostheses supported by Brånemark Implants (n = 589). As a result of fixture loss in each of two patients (two jaws), an overdenture instead of a fixed prosthesis was installed. For one patient (two jaws), data were not available after abutment connection. At the end of the seventh year, the cumulative failure rates for the remaining 99 prostheses reached 4.9% for mandibles and 10.1% for maxillae. After loading, 12 fixtures showed signs of nonintegration, but only one patient had to revert to complete dentures. Neither the fixture location nor the cantilever length revealed a significant difference in marginal bone loss around the supporting fixtures. Patients with fixture-supported fixed prostheses in both jaws showed significantly more marginal bone loss than did those with only one fixed prosthesis opposed by either natural dentition (50%) or a complete denture (50%). Component complications were limited to fixture fracture (3/564), abutment screw fracture (5/564), and gold screw fracture (7/564). The predictability of Brånemark implants in the treatment of completely edentulous jaws is confirmed.

The Influence of Surface Free-energy on Planimetric Plaque Growth in Man

The purpose of this study was to examine the change in plaque area over nine days in vivo on four materials with different surface free-energies (s.f.e.). Twelve healthy dental students participated in a crossover, split-mouth, double-blind study. Supragingival plaque formation was recorded over a nine-day period, on four different materials: fluorethylenepropylene (Teflon) (FEP), parafilm (PAR), cellulose acetate (CA), and enamel (E) with s.fe. of 20, 26, 57, and 88 erg/cm2, respectively. Strips made from the first three materials were stuck to the buccal surface of an upper incisor. The remaining incisor was carefully polished and served as an enamel surface. The increase in plaque was evaluated after three, six, and nine days. A planimetrical analysis was used so that the plaque area could be expressed as a percentage of the total buccal tooth surface. This procedure was repeated on each subject, so that at the end, each pair of central or lateral incisors received the four tested materials. The results indicated that the adherence of micro-organisms on pellicle-coated substrata was influenced by the materials s.f.e.; there was an association between the s.f.e. of the substrata and the supragingival plaque extension in vivo. High surface free-energy substrata in the oral cavity attracted more micro-organisms than did low energetic materials. Additionally, the bacterial adhesion seemed very weak on surfaces with a low s.f.e.

GC–MS analysis of breath odor compounds in liver patients

BACKGROUND Liver diseases can cause a sweet, musty aroma of the breath, called fetor hepaticus. Even in a stage of cirrhosis, the disease can be asymptomatic for many years. Breath analysis might be helpful to detect occult liver pathology. STUDY OBJECTIVE This study examined whether specific breath odor compounds can be found in liver patients, suffering from cirrhosis, which might be useful for diagnosis. MATERIALS AND METHODS Fifty-two liver patients and 50 healthy volunteers were enrolled. Alveolar air was analyzed by gas chromatography-mass spectrometry. Using discriminant analysis a model for liver disease was built. RESULTS Dimethyl sulfide, acetone, 2-butanone and 2-pentanone were increased in breath of liver patients, while indole and dimethyl selenide were decreased. Sensitivity and specificity of the model were respectively 100% and 70%. CONCLUSIONS Fetor hepaticus is caused by dimethyl sulfide and to a lower extent by ketones in alveolar air. Breath analysis by GC-MS makes it possible to discriminate patients with breath malodor related to hepatic pathologies.

Impact of local and systemic factors on the incidence of late oral implant loss

BACKGROUND This retrospective study was set to assess the influence of systemic and local bone and intra-oral factors on the occurrence of implant loss from abutment connection up to 2 years. MATERIALS AND METHODS The files of 700 patients, have been collected randomly from the total patient group treated by means of endosseous Brånemark system implants (Nobel Biocare, Gothenburg, Sweden) at the Department of Periodontology of the University Hospital of the Catholic University of Leuven. The end point observation was evaluating the loss of the implants 2 years after abutment installation. The study involved all implants that did not encounter early loss and implants for which it was possible to evaluate its status 2 years after abutment surgery. Thus, data of 412 patients (240 females) provided with 1514 implants were analyzed. For each patient, the medical history was carefully checked. Data collection and analysis were mainly focused on endogenous factors such as hypertension, coagulation problems, osteoporosis, hypo- hyperthyroidism, chemotherapy, diabetes type I or II, Crohns disease, some local factors [e.g. bone quality and quantity, implant (length, diameter, location), type of edentulism, PTV, radiotherapy], smoking habits, and breach of sterility during surgery. RESULTS Radiotherapy, implant (diameter and location), and higher PTV at implant insertion and abutment connection, all affected significantly the implant loss. CONCLUSION Implant location in the oral cavity and radiotherapy seem predominant to explain the occurrence of implant loss. On the other hand, smoking and systemic health factors do not seem to be prominent players in the etiology of late implant loss.

Characteristics of 2000 patients who visited a halitosis clinic

AIMS The aim of this paper was to analyse the aetiology and characteristics of 2000 patients who visited a multidisciplinary bad breath clinic in Leuven, Belgium and to correlate organoleptic ratings with portable device measurements. MATERIALS AND METHODS The characteristics and aetiology of breath malodour of two thousand consecutive patients who visited a halitosis consultation were explored by means of a standard questionnaire and a clinical examination, including organoleptic scores provided by a trained and calibrated judge, and a portable bad breath detector (Halimeter). RESULTS Most patients came without referral and had complaints for several years (mean: 7 years, SD: 8 years). For 76% of the patients, an oral cause was found [tongue coating (43%), gingivitis/periodontitis (11%) or a combination of the two (18%)]. Pseudo-halitosis/halitophobia was diagnosed in 16% of the cases; and ear, nose and throat/extra-oral causes were found in 4% of the patients. Most patients had an organoleptic score <3 and a Halimeter value <240 p.p.b. CONCLUSIONS Even though it was observed that halitosis has a predominantly oral origin, a multidisciplinary approach remains necessary to identify ear, nose and throat or extra-oral pathologies and/or pseudo-halitosis/halitophobia.

A comparative prospective study of splinted and unsplinted Brȧnemark implants in mandibular overdenture therapy: A preliminary report

Thirty-six edentulous patients, each provided with two Bränemark implants in the mandible to anchor an overdenture, were selected for this study and randomly divided into three groups of 12 patients each. In each group a different attachment system was used: (1) magnets, (2) ball attachments, and (3) straight bars with clips (control). The mean loading time was 12.4 months (range 3 to 24 months). This study investigated (1) the clinical behavior of loaded implants by means of overdentures related to their connection system (splinted versus unsplinted) and (2) the clinical performance of prosthetic treatment. Preliminary results indicate no differences; no failures occurred and the level of marginal bone height, as well as the probing attachment level, changed similarly in the three groups. Although splinted bar-retained overdentures scored better objectively, subjective satisfaction ratings did not differ. It was concluded that for the short follow-up period, the state of connection did not influence the clinical success of implants. However, no definite conclusions may be drawn until long-term data become available.

Time dependent failure rate and marginal bone loss of implant supported prostheses: a 15-year follow-up study

Abstract This study deals with 4971 implants (Brånemark system) installed in 1315 patients, either fully or partially edentulous, and followed from implant installation up to the last control. A predominance of female patients (61%) and a nearly equal number of upper and lower jaws characterised the study group. Patients were scheduled each 6–12 months for recall. The observation time varied from 0.5 to 15 years (mean 5.1). The whole cohort was split up into compromised (n=59) and non-compromised (n=1256) patients. The former are defined as grafted (autologous bone) and patients irradiated in the head and neck area. In the compromised patients 24 out of 59 patients (40.6%) showed failures, in whom 59 out of 310 (19%) implants failed. In the non-compromised patients, implant failures were observed in 11.6% of the patients, which corresponds to 5.9% of the installed implants, excluding iatrogenic failures. Failures were further divided chronologically into early (up to 1 year after abutment connection) and late failures. There were early implant failures in 12.5% of the compromised patients and in 3.4% of the others. Late implant failures occurred in 7.4 and 2% of the two patients groups, respectively. While gender did not affect the failure rate, implant lengths, corresponding to the available bone height did, since a 21.5% failure rate for the 7-mm implants contrasts with 4.1 and 3.8% for 13- and 15-mm implants, respectively. Early as well as annual late failures are more frequently found in the maxilla. Implant fractures only occurred in the fixed (both partial and full) prosthesis group but never surpassed the 0.2% annual level. Marginal bone loss, exceeding the third screw thread occurred in 1.8% of the implants at the last control. It appears that this type of implant configuration offers a high long-term predictability. Failures occur before, at or during the first year after abutment connection and in very short implants. Marginal bone as a whole is very stable over the years.

E.A.O. guidelines for the use of diagnostic imaging in implant dentistry 2011. A consensus workshop organized by the European Association for Osseointegration at the Medical University of Warsaw

Diagnostics imaging is an essential component of patient selection and treatment planning in oral rehabilitation by means of osseointegrated implants. In 2002, the EAO produced and published guidelines on the use of diagnostic imaging in implant dentistry. Since that time, there have been significant developments in both the application of cone beam computed tomography as well as in the range of surgical and prosthetic applications that can potentially benefit from its use. However, medical exposure to ionizing radiation must always be justified and result in a net benefit to the patient. The as low a dose as is reasonably achievable principle must also be applied taking into account any alternative techniques that might achieve the same objectives. This paper reports on current EAO recommendations arising from a consensus meeting held at the Medical University of Warsaw (2011) to update these guidelines. Radiological considerations are detailed, including justification and optimization, with a special emphasis on the obligations that arise for those who prescribe or undertake such investigations. The paper pays special attention to clinical indications and radiographic diagnostic considerations as well as to future developments and trends.