Prosthodontic complications during implant-based oral rehabilitation of patients with head and neck cancer.

STATEMENT OF PROBLEM: Implant-retained prosthodontic rehabilitation of patients with head and neck cancer is complex. However, the extent of prosthodontic complications has been sparsely reported within the literature. PURPOSE: The purpose of this retrospective study was to describe the range of complications and issues that affected the oral rehabilitation treatment of patients with head and neck cancer who had completed implant-retained prosthodontic rehabilitation in a tertiary treatment center. MATERIAL AND METHODS: A retrospective analysis of complications and their consequences in patients treated in a regional unit from 2012 to 2017 was performed. Descriptive analysis was carried out on the type and frequency of complications and their consequences for the patients' treatment. Complications were grouped into the following complication types: local and systemic, implant, peri-implant soft tissue, and clinical prosthodontic complications. Implant success and implant survival were also reported. RESULTS: The sample was composed of 163 patients with head and neck cancer who had completed implant-retained prosthodontic rehabilitation. Local and systemic complications affected 8.6% of patients, and peri-implant soft-tissue complications affected 9.8% of patients. Clinical prosthodontic complications leading to repeated clinical or laboratory stages occurred on 48 occasions in 45 patients (27.6% of patients). A total of 763 implants were placed. Implant survival was 95.8% and implant success 94.5%, with a mean follow-up of 42.1 months. CONCLUSIONS: This retrospective evaluation indicated that complications arising during the process of implant-retained prosthetic rehabilitation in this patient group were variable and common. Such complications can delay the process of treatment and lead to repeating or restarting clinical and laboratory stages of treatment.

Survival rate and complication-free survival rate of implant-retained prostheses in the oral rehabilitation of patients with head and neck cancer: A retrospective evaluation of a cohort from a regional service.

STATEMENT OF PROBLEM: Literature reporting on the prosthetic survival and complications of implant-retained prostheses in patients with head and neck cancer is sparse. PURPOSE: The purpose of this retrospective study was to present the survival rates and complication-free survival rates of both fixed and removable implant-retained oral prostheses in patients with head and neck cancer while also reporting on the frequency and causes of failure and complications for each prosthesis type. MATERIAL AND METHODS: A retrospective analysis of the prosthetic survival rates and complication-free survival rates of implant-retained oral prostheses and the frequency and causes of failure and complications in patients with head and neck cancer treated in a regional unit from 2012 to 2017 was performed. Differences in categorical and continuous data were assessed for statistical significance by using the Pearson chi-square test, Fisher exact test, t test, and analysis of variance as appropriate. Cox proportional hazard regression models were fitted to evaluate the association between prostheses type, clinical and medical factors, and the outcomes of survival and complication-free survival. Descriptive statistics were used to analyze the frequency and type of prosthetic complications. RESULTS: The sample was composed of 153 patients diagnosed with head and neck cancer who had completed implant-retained prosthodontic rehabilitation and had been provided with 221 prostheses. The 5-year survival rate was 87% for maxillary fixed prostheses, 79% for mandibular fixed, 66% for maxillary removable, and 50% for mandibular removable. Hazard ratios were calculated showing that the 5-year survival rate of a mandibular removable prosthesis (HR=5.1; 95% CI 1.60-16.25) (P=.006) was greater than that of a maxillary fixed prosthesis (HR=1.0). The 5-year complication-free survival rate was highest for mandibular fixed prostheses (62%), followed by maxillary fixed (58%), maxillary removable (36%), and mandibular removable prostheses (29%). Hazard ratios showed that the 5-year survival rate of maxillary removable (HR=1.91; 95% CI 1.01-3.66) (P=.048) and mandibular removable prosthesis (HR=2.29; 95% CI 1.23-4.25) (P=.009) was greater than that of a maxillary fixed prosthesis (HR=1.0). Variables of radiotherapy, grafting, age, and sex and their influence on the survival rate and complication-free survival rate were assessed but were not statistically significant. CONCLUSIONS: This evaluation indicated that fixed implant-retained prostheses had a higher 5-year survival rate and 5-year complication-free survival rate than removable implant-retained prostheses in patients with head and neck cancer.

Outcomes of implant-based oral rehabilitation in head and neck oncology patients-a retrospective evaluation of a large, single regional service cohort.

BACKGROUND: The study reports on implant survival outcomes in head and neck cancer patients who received implant-based oral rehabilitation in a regional service centre. METHODS: A retrospective analysis of implant survival outcomes in patients treated in a regional service from 2012 to 2017 was performed. The primary outcome measure was implant survival. The secondary outcome measure was to assess the effect of covariates associated with implant failure including bone type, radiotherapy, chemotherapy, gender and surgical implant complications. Kaplan-Meier survival curves were applied to compare differences in the survival rates of groups of variables. Cox proportional hazards models were applied to identify covariates associated with implant failure. p value was set at 0.05. RESULTS: The sample was composed of 167 head and neck cancer patients who had 779 dental implants placed. Implant survival estimates were calculated: 3 years, 95.7% [95%CI 94.3-97.2%] and 5 years, 95.5% [95%CI 93.9-97.0%], with a median follow-up of 38 months. Gender (p = 0.09), radiotherapy (p = 0.16) and chemotherapy (p = 0.17) did not significantly influence implant survival, whereas implant failure was higher in transported (reconstructed) bone sites in comparison with native bone (p < 0.01). CONCLUSION: The result of this study suggests that overall implant survival as part of the routine oral rehabilitation is high in this patient cohort; however, implant failure was found to be statistically higher for implant placed into transported bone in comparison to native bone.

Mineral trioxide aggregate use in failing endodontic treatment--a case report.

UNLABELLED: Management of failing endodontic treatment may present significant challenges. The following case report describes the use of a contemporary endodontic material--Mineral Trioxide Aggregate (MTA). Successful resolution of endodontic disease was accomplished through a combined orthograde and retrograde approach. CLINICAL RELEVANCE: Contemporary endodontic techniques can provide good success rates in challenging cases. In particular, the material MTA now has a proven track record of performance and reliability in clinical research, and should gain widespread acceptance in general dental practice.

Principles of crown lengthening surgery.

UNLABELLED: Crown lengthening is an invaluable tool for the restorative dentist in the management of short clinical crown heights. This procedure, as an adjunct to a holistic restorative treatment plan, can produce predictable results, whilst ensuring good aesthetics and maintaining periodontal health. Crown lengthening procedures are invaluable where toothwear or lack of supragingival tooth substance would render full coverage restoration difficult. Gaining access to subgingival caries for strategic abutments can also be achieved in this way. In certain instances, excessive gingival show or inharmonious gingival margin levels can be aesthetically managed with crown lengthening procedures. CLINICAL RELEVANCE: Knowledge of crown lengthening techniques, and where these might be prescribed, may be a useful addition to practitioners' treatment planning options, or to decide when referral may be more appropriate.

Mucogingival grafting procedures--an update.

UNLABELLED: Gingival recession is the exposure of the root surface due to the apical migration of the gingival margin. It is a common feature in the general population and can often lead the patient to seek treatment. Mucogingival therapy may be required to prevent further recession, correct aesthetic problems, aid plaque control and reduce dentine hypersensitivity. There are several different mucogingival treatment approaches which usually involve the manipulation of the patient's tissues to augment the gingivae and cover the exposed root. This article reviews the management procedures that are indicated for the treatment of gingival recession. CLINICAL RELEVANCE: To make the dental practitioner aware of the different surgical modalities available for the treatment of gingival recession and improve his/her ability to identify patients who might benefit from them.

Contemporary periodontal surgery: 2. Surgical practice.

UNLABELLED: Contemporary surgical techniques emphasize gentle tissue handling with a minimum of trauma. This in turn provides a predictable operative environment and promotes healing. A modern surgical armamentarium may be very different from that encountered a decade ago. This is clear from the greater availability of dental microsurgical instruments. Whilst the complexity of microsurgery may not be routinely necessary in general dental practice, many of the principles and equipment used may make standard surgical management easier and more predictable. CLINICAL RELEVANCE: A greater understanding of the evidence base behind periodontal surgery will allow us to improve flap design, closure and operative management. Also, the use of microsurgical techniques and equipment will improve the quality and outcomes of periodontal surgery in practice.

Contemporary periodontal surgery: 1. Surgical principles.

UNLABELLED: Periodontal surgery comprises surgical intervention of the supporting tissues of the teeth. This ranges in complexity from simple exodontia to technically demanding periodontal plastic surgery and includes the management of periodontal diseases, implant placement and preparatory treatment for fixed and removable prostheses. Modern surgical management reflects both a move towards evidence-based practice and the introduction of improved techniques and armamentarium. General principles of surgical management hold true regardless of what procedure is being carried out. These principles form a sound basis for any practitioner contemplating surgical interventions for their patients. CLINICAL RELEVANCE: A sound understanding of first principles will simplify periodontal surgical management. Careful surgical preparation will render surgical procedures more predictable and reduce post-operative discomfort.

Microdochium triticicola sp. nov. from roots of Triticum aestivum in the United Kingdom.

Morphological and molecular studies led to the description of Microdochium triticicola as new species isolated from roots of wheat in the United Kingdom. The morphological features of all known Microdochium species are tabulated.

Heteroconium sp. nov. from roots of Triticum aestivum in the United Kingdom.

Morphological and molecular studies led to the description of Heteroconium triticicola as a new species isolated from roots of wheat in the United Kingdom. The new fungus shares with H. citharexyli, the type species of Heteroconium Petrak, features such as superficial mycelium, macronematous, mononematous, unbranched, straight conidiophores, monoblastic, integrated, terminal, cylindrical conidiogenous cells, and catenate, dry, simple, cylindrical, obclavate, often pale brown, smooth, multiseptate conidia. The genus Heteroconium is proposed as an anamorph within Hyaloscyphaceae.

Phylogenetic relationships among Zygomycetes from soil based on ITS1/2 rDNA sequences.

New information was obtained on the phylogeny of Zygomycetes. PCR-RFLP analysis showed ITS1/2 rDNA to provide appropriate markers for genetic studies on Zygomycetes at the population and species levels. The use of several restriction enzymes allowed discrimination between genera and species of Mortierellales and Mucorales. ITS1/2 sequence analysis clearly indicated a deep, ancient and distinct dichotomy of Mortierellales and Mucorales. The data do not fully support the current concept of Mucorales, which recently included the family Umbelopsidaceae, but support the distinctiveness of the Umbelopsis group, which includes Mortierella turficola. The data support the hypothesis of polyphyly of Absidia and are consistent with the hypothesis of polyphyly of Mucor.

Retention of quartz-fibre endodontic posts with a self-adhesive dual cure resin cement.

This study examines retention of a quartz-fibre endodontic post cemented in extracted human teeth using two cement types. Fifty-four extracted buman central incisor teeth were prepared for a tapered quartz-fibre post. Posts were cemented in 28 teeth using conventional resin cement (RelyX ARC), and 26 teeth using self-adhesive resin cement (RelyX Unicem). Posts were cyclically-loaded. Bond strengths were tested and dependability assessment was carried out. Although there was no significant difference in Weibull modulus between groups (p < 0.05), greater dependability was displayed by RelyX Unicem group. Easy application and greater dependability of self-adhesive cement may improve bonding of fibre-based posts in root canals.

Mode of action and pesticidal activity of the natural product dunnione and of some analogues.

This paper reports the investigation of the insecticidal and fungicidal activity of dunnione, a natural product obtained inadvertently as a by-product of a synthesis programme. Dunnione exhibits no insecticidal activity but has an unusually broad spectrum of antifungal activity. In vitro and in vivo (preventative) activities were comparable to those of several long-established fungicides (eg carbendazim). However, in whole-plant assays, its eradicant activity was unexpectedly low, probably due to poor dose-transfer from leaf surface to fungus. The level of residual activity appears to be influenced by the formulation. Finally, its potential as a lead structure was assessed, and several analogues synthesised which exhibited high activity in the in vitro assays. Mode-of-action studies revealed that dunnione exerts its action primarily through initiation of redox cycling. This contrasts to the activity of BTG 505, the biochemical/chemical precursor, which does not initiate redox cycling but instead exhibits both insecticidal and fungicidal activity by inhibiting mitochondrial Complex III.

Variation in the effects of take-all disease on grain yield and quality of winter cereals in field experiments.

Relationships between take-all intensity and grain yield and quality were determined in field experiments on cereal crops using regression analyses, usually based on single-point disease assessments made during anthesis or grain-filling. Different amounts of take-all were achieved by different methods of applying inoculum artificially (to wheat only) or by using different cropping sequences (in wheat, triticale or barley) or sowing dates (wheat only) in crops with natural inoculum. Regressions of yield or thousand-grain weight on take-all intensity during grain filling were similar to those on accumulated disease (area under the disease progress curve) when these were compared in one of the wheat experiments. Regressions of yield on take-all intensity were more often significant in wheat than in the less susceptible crops, triticale and barley, even when a wide range of disease intensities was present in the latter crops. The regressions usually had most significance when there were plots in the severe disease category. Thousand-grain weight and hectolitre weight usually responded similarly to total grain yield. Decreased yield was often accompanied by a significant increase in the percentage of small grains. When severe take-all was present in wheat, regressions showed that nitrogen uptake was usually impaired. This was sometimes accompanied, however, by increased percentage nitrogen in the grain as a consequence of smaller grain size with decreased endosperm. Significant effects of take-all, both positive and negative, on Hagberg falling number in wheat sometimes occurred. Significant regressions of yield on take-all assessed earlier than usual, ie during booting rather than grain-filling in wheat and triticale and during anthesis/grain-filling rather than ripening in barley, had steeper slopes. This is consistent with observations that severe disease that develops early can be particularly damaging, whilst the crops, especially barley, can later express tolerance by producing additional, healthy roots. The regression parameters, including maximum potential yield (y-axis intercept) and the extrapolated maximum yield loss, also varied according to the different growing conditions, including experimental treatments and other husbandry operations. These differences must be considered when assessing the economic potential of a control measure such as fungicidal seed treatment.

Comparison of Gaeumannomyces- and Phialophora-like fungal pathogens from maize and other plants using DNA methods.

Several DNA-based techniques, developed for identifying and differentiating fungi in the Gaeumannomyces-Phialophora complex associated with take-all diseases of cereals and grasses, were used to compare fungi from maize. Maize isolates obtained as G. graminis (Sacc.) Arx & H Olivier var. tritici Walker, from the UK, having been identified by ascospore morphology and in pathogenicity tests on wheat, were indistinguishable from isolates of the same variety obtained from wheat. Isolates of G. graminis (Sacc.) Arx & H Olivier var. maydis Yao et al., recently described as the maize take-all fungus from China, were identical in DNA tests to the anamorphic fungus Phialophora radicicola Cain and almost identical to Phialophora zeicola Deacon & Scott, whose description was originally based on isolates from South Africa and France. These species appear to represent the holomorph of the same fungus. The late wilt pathogen of maize, from India and Egypt, commonly known as Cephalosporium maydis Samra et al., but suggested as being the Phialophora anamorph of a Gaeumannomyces species, was closely related to other Gaeumannomyces species included in the tests.