Sliding reconstruction of the condyle using posterior border of mandibular ramus in patients with temporomandibular joint ankylosis

The traditional approach for ankylosis is gap arthroplasty or interpositional arthroplasty followed by reconstruction of the condyle using, for example, costochondral grafts. As these are non-pedicled grafts, there is eventual resorption with subsequent decrease in height of the ramus, facial asymmetry and deviated mouth opening. The authors have applied the method of total and partial sliding vertical osteotomy on the posterior border of the mandibular ramus for reconstruction of the mandible condyle as a pedicled graft for the correction of temporomandibular joint (TMJ) ankylosis. From 2004 to 2008, 18 patients who were diagnosed with TMJ ankylosis underwent operations for resection of the ankylosed condyle. Two methods were performed depending on the level of osteotomy on the posterior part of the mandibular ramus. All patients were followed-up for an average of 36 months (range 24-48 months). All patients showed apparent improved joint function with no cases of re-ankylosis. The results showed that sliding vertical osteotomy on the posterior border of the mandibular ramus seems to be an alternative and promising method for condylar reconstruction in patients with TMJ bony ankylosis.     

Effects of low-energy CO2 laser irradiation and the organic matrix on inhibition of enamel demineralization

In the past two decades, accumulated evidence has clearly demonstrated the inhibitory effects of laser irradiation on enamel demineralization, but the exact mechanisms of these effects remain unclear. The purpose of this study was to investigate the effects of low-energy CO2 laser irradiation on demineralization of both normal human enamel and human enamel with its organic matrix removed. Twenty-four human molars were collected, cleaned, and cut into two halves. One half of each tooth was randomly selected and its lipid and protein content extracted. The other half of each tooth was used as the matched control. Each tooth half had two window areas. All the left windows were treated with a low-energy laser irradiation, whereas the right windows served as the non-laser controls. After caries-like lesion formation in a pH-cycling environment, microradiographs of tooth sections were taken for quantification of demineralization. The mean mineral losses (with standard deviation) of the enamel control, the lased enamel, the non-organic enamel control, and the lased non-organic enamel subgroups were 3955 (1191), 52(49), 4565(1311), and 1191 (940), respectively. A factorial ANOVA showed significant effects of laser irradiation (p = 0.0001), organic matrix (p = 0.0125), and the laser-organic matrix interaction (p = 0.0377). The laser irradiation resulted in a greater than 98% reduction in mineral loss, but the laser effect dropped to about 70% when the organic matrix in the enamel was removed. The results suggest that clinically applicable CO2 laser irradiation may cause an almost complete inhibition of enamel demineralization.     

Human ameloblastoma tumors express the amelogenin gene.

Instructive signals are responsible for the regulation of the expression of gene products characteristic of many cell lineages during normal development and potentially during neoplasia. The odontogenic origin of ameloblastomas is based largely on the similarity in histologic appearance between the tumor and the developing tooth organ. A pathognomonic pattern for odontogenic tissue-specific gene expression in ameloblastomas has not been previously shown. In these studies, the gene expression parameters for human ameloblastomas have been characterized with the techniques of messenger RNA phenotyping in combination with Northern and in situ hybridization analysis of messenger RNA. The results of these studies confirm that amelogenin, a gene transcribed solely by differentiated ameloblasts, was expressed by epithelial cells from human ameloblastomas. This observation suggests that the instructive signals required for ameloblast differentiation are shared during normal development and tumorigenesis of odontogenic epithelium.     

A comparative analysis of the accuracy of implant transfer techniques

Four different implant transfer techniques using two master cast systems (solid cast and Zeiser system) were evaluated and compared with respect to the accuracy with which abutment positions were reproduced. A stainless steel experimental analogue with two anterior and two posterior fixtures and abutments was fabricated. Polyether impressions (14 each) were made by use of four techniques, (I) nonsplinted, (II) splinted with dental floss and acrylic resin, (III) splinted with orthodontic wire and acrylic resin, and (IV) splinted with acrylic resin alone. The fourteen impressions of each technique were divided into two equal groups: group 1, solid cast system, and group 2, Zeiser system. The abutments of each master cast were measured vertically and horizontally with a profile projector. Statistical analysis indicated no significant difference between the splinted and nonsplinted techniques. The Zeiser system provided more accurate interabutment relationships for the posterior region than the solid cast system.     

Real-time quantitative polymerase chain reaction for enumeration of Streptococcus mutans from oral samples

This study compared SYBR Green real-time quantitative PCR (qPCR) with standard plate counting for the enumeration of Streptococcus mutans in oral samples. Oral samples (n = 710) were collected from high-caries-risk children for quantification of S. mutans by qPCR using primer pairs. The S. mutans copy number was calculated with reference to a qPCR quantification cycle (Cq) standard curve and compared with the absorbance value at 600 nm of a standard suspension of S. mutans UA159. The S. mutans copy number results were evaluated in relation to standard plate count (SPC) results obtained from each sample following culture on Petri plates containing S. mutans selective media and reported as colony-forming units (CFUs). The mean S. mutans copy number calculated from qPCR was higher than the SPC CFUs (1.3 × 10(6) and 1.5 × 10(5) CFUs, respectively). The qPCR values were usually higher in individual samples and qPCR detected the presence of S. mutans 84% (231/276) of the time that the SPC did not, compared with 33% (4/12) of the time when qPCR failed to detect S. mutans and the SPC did. The qPCR technique was found to be more sensitive for detection of S. mutans from oral samples, a method that is not dependent on the viability of the sample taken and therefore is proposed as a more reliable and efficient means of quantification of S. mutans.     

Systematic review of negative pressure wound therapy for head and neck wounds with fistulas: Outcomes and complications

Fistula formation in head and neck wounds is considered one of the most challenging complications that a head and neck reconstructive surgeon may encounter. The current mainstay of treatment is aggressive surgical debridement followed by vascularised soft tissue coverage. Negative pressure wound therapy (NPWT) has been successfully used for the closure of complicated wounds for decades. This study analysed the outcomes and complications of NPWT in the management of head and neck wounds with fistulas. A systematic search of studies published between January 1966 and September 2019 was conducted using the PubMed, MEDLINE, EMBASE, and SCOPUS databases and using the following key words: “negative pressure wound therapy,” “head and neck,” and “fistula.” We included human studies with abstract and full text available. Analysed endpoints were rate of fistula closure, follow‐up duration, and complications if present. Nine retrospective case series (Level IV evidence) that collectively included 122 head and neck wounds with orocutaneous fistulas, pharyngocutaneous fistulas, and salivary contamination were examined. The number of patients included in each study ranged from 5 to 64. The mode of NPWT varied among the included studies, with most adopting a continuous pressure of −125 mm Hg. Mean durations of NPWT ranged from 3.7 to 23 days, and the reported fistula closure rate ranged from 78% to 100%. To achieve complete wound healing, six studies used additional procedures after stopping NPWT, including conventional wound dressings and vascularised tissue transfer. Information regarding follow up was provided in only three of the nine studies, where patients were followed for 5, 10, and 18 months. No serious adverse events were reported. NPWT for head and neck wounds with fistulas may be considered a safe treatment method that yields beneficial outcomes with a low risk of complications. The current data originated mainly from studies with low levels of evidence characterised by heterogeneity. Therefore, definitive recommendations based on these data cannot be offered. Additional high‐quality trials are warranted to corroborate the findings of this systematic review.     

COVID‐19 in a high‐risk dual heart and kidney transplant recipient

The severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) is rapidly infecting people worldwide, resulting in the infectious disease coronavirus disease 19 (COVID‐19) that has been declared a pandemic. Much remains unknown about COVID‐19, including its effects on solid organ transplant (SOT) recipients. Given their immunosuppressed state, SOT recipients are presumed to be at high risk of complications with viral infections such as SARS‐CoV‐2. Limited case reports in single SOT recipients, however, have not suggested a particularly severe course in this population. In this report, we present a dual‐organ (heart/kidney) transplant recipient who was found to have COVID‐19 and, despite the presence of a number of risk factors for poor outcomes, had a relatively mild clinical course.