Functional outcomes after organ preservation treatment in head and neck cancer: a critical review of the literature.

The use of radiation therapy and/or chemotherapy in advanced head and neck cancer is increasing in popularity, driven by the notion that sparing the organs of speech and swallowing from surgical resection will also spare function. This critical review of the literature considered functional outcomes after organ preservation to assess the impact of such treatment on speech, swallowing and quality of life in patients with head and neck cancer. Literature searches were conducted on several library databases. A total of 50 relevant articles were identified and found to meet the inclusion criteria specified a priori. The majority of reports suggested that organ preservation techniques have the potential to result in swallowing disorders, often related to dysmotility of the oropharyngeal and laryngeal structures, and resulting in frequent episodes of aspiration. This may lead to the need for enteral feeding in the short term for some patients while, in others, this need is life long. Speech does not appear to be affected to the same degree as swallowing. These results suggest that organ preservation does not translate into function preservation for all patients with head and neck cancer.

The use and abuse of the Periotest for 2-piece implant/abutment systems.

While the Periotest continues to be used in assessing the integrity of implants, there are numerous reports of its inconsistencies. To understand more precisely what the Periotest is actually measuring, a mathematical model was developed that illustrates the effect that various geometric and clinical parameters have on the Periotest value (PTV). In addition, the model was validated with an in vitro experiment. Results of the mathematical model are shown to correlate with those obtained from the experimental test The PTV is very sensitive to the position at which the Periotest impacts the abutment and to angulation of the handpiece. It was shown that a change in position of 1 mm in striking height can produce a difference in PTV of between 1 and 2. Since the angulation of the handpiece can produce a difference in striking position of 2 mm, it must be controlled as well. The model also showed that the Periotest can detect changes in bone height of 0.5 mm.

Proteomic analysis of human skin fibroblasts grown on titanium: novel approach to study molecular biocompatibility.

Despite the growing use of titanium as an implant material, there is a lack of consensus on what constitutes the molecular basis of its biocompatibility. In the present study we compared the response of skin fibroblasts to two different growth supporting surfaces: commercially pure titanium (cpTi) and tissue culture polystyrene (TCPS). Proteins from extracts of whole cells and adsorbed serum were separated and identified by 2-dimensional gel electrophoresis. In all, 40 proteins (46 spots) were identified by matrix-assisted laser desorption/ionization and mass spectrometry, database searching, immunoblotting, running a standard, or a combination of these techniques. Many of the proteins collected from the two surfaces were found to derive from the serum used in the culture medium. The surface properties of titanium appeared to promote the formation of a more concentrated carpet of serum proteins. Several proteins from bovine or human serum, such as albumin, alpha2-HS-glycoprotein, alpha-fetoprotein, plasminogen, thrombospondin 1, and serotransferrin, along with a few unidentified serum components, were found to adsorb onto cpTi in comparatively high concentrations. The adsorption of serum proteins did not appear to be selective on either substrate. We found that among the major cellular proteins, fibronectin and a cytoskeletal protein (non-muscle myosin heavy chain type A) were expressed at lower levels by fibroblasts grown on cpTi compared to TCPS. By analyzing the changes in the entire proteome of cells in response to different growth substrates, we may gain a better understanding of the molecular basis of biocompatibility.

Patients with reconstruction of craniofacial or intraoral defects: development of instruments to measure quality of life.

Patients with reconstruction of craniofacial or intraoral defects experience a profound impact on their quality of life (QOL). This impact on QOL is influenced by the patients' medical conditions and the treatment interventions. Instruments to measure general QOL have been available for many years. A major criticism of QOL instruments is that too often the questions are not specific to the particular problems of a disease or condition. A search of the literature regarding QOL measurement for patients with maxillofacial implant-supported prostheses produced a short list of instruments, none of which were sufficiently developed or suited to the patients involved in reconstructive treatment. This study was designed to develop pretreatment and posttreatment questionnaires for measuring QOL for patients with reconstruction of a craniofacial defect and patients with reconstruction of loss of specific intraoral structures utilizing an implant-supported prosthesis (e.g., severe resorption of the maxilla or mandible or both). The goal was to develop brief, targeted instruments for this specific patient population. The produced instruments were sensitive and easy to administer and score, and no disruption of clinical care occurred with the administration of the questionnaires. The instruments were used with equal success both in face-to-face interviews and via mail.

Quantifying the adherence of fibroblasts to titanium and its enhancement by substrate-attached material.

Normal human skin fibroblasts were cultured on tissue culture polystyrene and on commercially pure titanium. In addition, substrate-attached material that remained on the surfaces after detachment of fibroblasts with a chelating agent was examined. The force required to detach 50% of the fibroblasts from each substrate was assessed by centrifugation. The results showed a time-dependent decrease in the force required to detach fibroblasts from titanium not seen on tissue culture polystyrene. Nearly all cells detached from the titanium surfaces at 7.85 x 10(x3) dynes/cell after 3 or 5 days in culture, whereas few cells detached from tissue culture polystyrene. Cells freshly seeded onto titanium substrates that had been coated with substrate-attached material by prior culture of fibroblasts for 3 or 5 days showed an approximately sixfold increased adherence. The results of immunofluorescence staining for fibronectin and its receptor suggest that the nature of the interaction between this extracellular matrix ligand and the substrate may be important in determining cellular stiffness at the cell-extracellular matrix interface.

Measuring abutment/implant joint integrity with the Periotest instrument.

Maintenance of the integrity of the abutment/implant interface is essential and is dependent on the abutment screw retaining a preload. Evaluation of this joint is usually done by manual assessment. The purpose of the current study was to determine whether the Periotest instrument could be used to evaluate abutment screw loosening. A custom-designed apparatus was constructed to measure abutment screw loosening. Abutment screws were torqued to 10, 20, 32, and 45 Ncm and then loosened. Objective assessment of screw loosening was carried out with the Periotest device. Subjective evaluation was done by 3 experienced clinicians. The Periotest was found to be more sensitive than manual detection of abutment screw loosening. With a change of 2 in the Periotest value, it was found that the tensile preload in the joint was lost. While the Periotest was more sensitive than manual evaluation, the instrument was not sensitive enough to indicate deterioration of abutment screw loosening prior to loss of tensile preload.

The influence of dentures on nasalance values in speech.

OBJECTIVE: The purpose of this study was to investigate the effects of maxillary dentures on nasalance values in normal elderly individuals. DESIGN: A three-factor within-subjects experimental design was employed to analyze the nasalance scores obtained. PARTICIPANTS: Twenty English-speaking women aged 61 to 81 years, who wore complete maxillary dentures, participated in the study. INTERVENTION: A Nasometer was used to collect nasalance data. Participants read three standard passages aloud, three times each, in two conditions: with and without their maxillary dentures. RESULTS: Results revealed that nasalance values were significantly lower with the maxillary dentures removed (p<.01), although the difference in nasalance between the two denture conditions averaged no more than 2%. Nasalance scores obtained both with and without maxillary dentures fell within one standard deviation of the mean for a reference group of comparably aged English-speaking women. CONCLUSIONS: The results suggest that the existing collection of normal reference data for nasalance may be safely used for elderly individuals regardless of their status with respect to natural or prosthetic maxillary dentition.

Craniofacial osseointegration: technique for bar and acrylic resin substructure construction for auricular prostheses.

Retention of auricular prostheses with adhesives is frequently problematic. Craniofacial osseointegrated implants have become an accepted biotechnique used in auricular reconstruction. This article describes a procedure for bar and acrylic resin substructure construction that allows for the incorporation of desired features. The most common means of retaining auricular prostheses is with bar and clip systems. For auricular prostheses, two implants are placed with the bar designed to minimize torquing on the implants and to facilitate hygiene. Additionally, the bar should not have to be removed from the patient when new prostheses are to be constructed. The procedure provides for a more biomechanically effective bar construction and efficient means of constructing replicate acrylic resin substructures.

Autogenous soft-tissue procedures and osseointegrated alloplastic reconstruction: their role in the treatment of complex craniofacial defects.

Between 1990 and 1994, twenty-seven patients with extraoral craniofacial defects were treated at the Craniofacial Osseointegration and Maxillofacial Prosthetic Rehabilitation Unit in Edmonton. Fourteen patients required management by a combination of alloplastic and autogenous techniques to optimize their reconstructive result. Autogenous soft-tissue procedures were performed almost twice as often in patients whose deformity was the result of trauma. Autogenous soft-tissue procedures included soft-tissue expansion, static facial slings, free and pedicled vascularized bone grafts, eyebrow reconstruction, brow lifts, and scar revisions. These reconstructive procedures are illustrated in three cases.

Removable partial denture design in Alberta dental practices.

Studies published in the dental literature have found, all too frequently, that dentists do not pay adequate attention to the design of cast removable partial denture frameworks. This study investigated removable partial denture design in Alberta dental practices. The authors considered various issues related to surveying, partial denture design, and provider education, as well as the possible collaboration of clinical dentistry with denturism in removable partial denture treatment. Although the study found that a significant proportion of Alberta's dentists get involved in designing the cast framework, relatively few undertake surveying. Instead, surveying tends to be deferred to dental technicians. As was the case in other studies, no clear reason for this trend emerged, and it appeared to be unrelated to remuneration or time utilization issues. Responding dentists perceived that their undergraduate education was adequate for providing removable partial denture care. The study also identified a need for small, hands-on continuing education courses. About half of the respondents indicated that it is appropriate for dentists to collaborate with denturists on complete denture care. However, very few respondents considered it appropriate to refer to, or collaborate with, denturists in removable partial denture care.

An impression and cast construction technique for implant-retained auricular prostheses.

Implant-retained auricular prostheses present a challenge with regard to the esthetic placement of the margins of the prosthesis. A technique for the impression and master cast fabrication to produce an implant-retained auricular prosthesis is described. This technique allows control of the esthetic margin, fabrication of a durable master cast with planned blockout, and inclusion of a replica of the retentive bar, which allows processing duplicate prostheses without returning the retentive bar to the mold.

Assessment of the periotest device in baseline mobility measurements of craniofacial implants.

The present study aimed to evaluate reliability of the Periotest instrument in baseline mobility measurement of craniofacial implants in a human wet bone specimen. Sixteen 4.0-mm craniofacial Brånemark implants were placed in the most common sites for craniofacial implant placement. A 5.5-mm abutment was attached to each implant except one in the mastoid bone, which was connected with a bone-anchored hearing aid (BAHA) abutment. Baseline Periotest values (PTVs) were recorded on each abutment at different vertical measurement points by three different clinicians using three Periotest devices. Baseline PTVs for each abutment ranged between -1.23 and -5.90. Interoperator and interinstrumental variability did not influence PTVs; however, the vertical measurement point on the abutment proved to have a strong effect on PTV recordings.

Craniofacial osseointegration.

Craniofacial osseointegration has been hailed as the most significant advance in maxillofacial prosthetic restoration over 25 years. It provides a particularly unfortunate group of patients, who previously may have had few treatment options, with new reconstructive opportunities. This paper outlines the surgical and prosthetic techniques of craniofacial osseointegration. Treatment outcomes in terms of individual implant success rates are described and the role of hyperbaric oxygen is considered. The need for future avenues of development are also discussed. Craniofacial implants have become an integral part of the treatment options available for head and neck reconstruction. It is important that this care is provided within a multidisciplinary clinical-research environment.

Ribosomal RNA sequence phylogeny is not congruent with ascospore morphology among species in Ceratocystis sensu stricto.

The genus Ceratocystis sensu stricto includes important fungal pathogens of woody and herbaceous plants. This genus is distinguished from species in Ceratocystis sensu lato by the presence of Chalara anamorphs. Ascospore shape has been used extensively in delineating Ceratocystis taxa, which show a large variety of ascospore shapes. Sequence analysis of one region of he 18S ribosomal RNA subunit and two regions of the 28S ribosomal RNA subunit showed that there was a majority of multiple substitutions at nucleotide sites and that there was a low transition/transversion ratio, T = 0.72. Both of these results suggest that these are well established, old species. Ascospore morphology, for the most part, was not congruent with the molecular phylogeny, and the use of morphological characters may be misleading in the taxonomy of these species.

Osseointegrated alloplastic versus autogenous ear reconstruction: criteria for treatment selection.

Fifty-five patients with major ear deformities were reconstructed during the period 1982-1993 with autogenous tissue. Fourteen patients were reconstructed with osseointegrated auricular prostheses during the period 1989-1993. Both procedures were done at the same institution by the same surgeon. The advantages and disadvantages of each approach were considered, and our criteria for treatment selection were developed. Our main indications for autogenous reconstruction include classical microtia, relatively normal lower one-third of the ear, patient preference, and less compliant patients. The main indications for osseointegrated alloplastic reconstruction include following major cancer extirpation, poor local tissue, absence of the lower half of the ear, salvage following unsuccessful autogenous reconstruction, and poor operative risks. Because of their success, osseointegrated auricular reconstructions should be added to the armamentarium of the reconstructive surgeon.

Effects of disinfecting irreversible hydrocolloid impressions on the resultant gypsum casts: Part III--Dimensional changes.

This study evaluated the effect of disinfection time (10, 30 and 60 minutes) on the dimensional changes of stone casts poured against an irreversible hydrocolloid impression material (Jeltrate). Impressions were made of a stainless steel analog of a maxillary arch. The impressions were sprayed with bleach, iodophor, phenol, and water and were stored for designated times before poured in a type IV stone (Vel-mix). The arch width, length, and depth of the vault of the resultant casts were measured by use of a contact measuring device (MicroVal) capable of measuring to 0.0001 mm. Data were analyzed with two-way analysis of variance at the 95% confidence level. Results indicated that disinfection treatment of alginate impressions with surface disinfectants did not cause significant dimensional changes in the resultant stone casts from statistical and clinical points of view.

A comparison of various removable partial denture clasp materials and fabrication procedure for placing clasps on canine and premolar teeth.

There is no established protocol for selection among the different retentive material-attachment combinations for clasps other than tradition or laboratory preference. Various wrought-wire, cast-metal, and thermoplastic materials were subjected to several fabrication procedures and tested in a custom-designed force displacement apparatus. The wrought wires included ADA Spec. No. 7 type I and type II alloys and other precious and nonprecious alloys. A graphic means was devised to allow the rational selection of wrought-wire clasp-arm combinations for placing clasps on canine and premolar teeth. Guidelines for using straight wire data for curved wire applications are indicated.

Effects of disinfecting irreversible hydrocolloid impressions on the resultant gypsum casts: Part I--Surface quality.

This study evaluated the effects of disinfection time (10, 30, and 60 minutes) on the surface quality of stone casts poured against an alginate impression material (Jeltrate). Five antimicrobial agents were tested: Sporicidin spray, sodium hypochlorite, and iodophor for spray; and Sporicidin cold sterilization solution and Cidexplus glutaraldehyde solution for immersion. Impressions, flushed with water and stored for 0, 10, 30, and 60 minutes before pouring, served as untreated controls. On completion of the disinfection treatments, the impressions were rinsed and poured in Velmix stone. The effects on cast surface were evaluated under a stereomicroscope by three experienced raters. A 1-to-4 scoring system was developed to rate the surface quality in terms of smoothness and detail reproduction. Both immersion disinfectants proved to be unacceptable for treating alginate impressions. The mean scores of other disinfectant-time combinations were compared with the use of the Tukey-Kramer method with a 95% confidence interval. The results indicated that treatment time had statistically significant effects on the quality of cast surface in Sporicidin spray, sodium hypochlorite, and untreated control groups but not in the iodophor spray group.