Evaluation of the surface damage of dental implants caused by different surgical protocols: an in vitro study.

The implant surface must withstand high insertion torque during implant insertion. The aim of this study was to investigate the damage to implant surfaces caused by two different insertion protocols in vitro. Fifteen titanium implants per group were inserted in standardized polyurethane foam models, group 1 according to a non-threaded surgical protocol and group 2 according to a threaded surgical protocol. Before and after insertion, the surfaces were visualized by scanning electron microscopy (SEM) and non-contact laser profilometry. Different surface area parameters were evaluated and maximum torque during insertion was determined. SEM detected topographical changes such as deposition of the test block and smoothening of the surface in the region of the thread crests in both groups. The laser profilometry analysis revealed significant changes in the surface topography of the implants in both groups, but no differences between the groups. Insertion torque was significantly decreased in the threaded group. Both types of surgical intervention resulted in surface damage. Less damage was detected to the thread crests with the use of a thread cutter, and most of the surface was not visibly affected by the surgical protocol at the microscopic level. The surgical protocol seems to have a minor influence on preservation of the implant surface.

A retrospective analysis of preoperative staging modalities for oral squamous cell carcinoma.

BACKGROUND: An accurate preoperative assessment of cervical lymph node status is a prerequisite for individually tailored cancer therapies in patients with oral squamous cell carcinoma. The detection of malignant spread and its treatment crucially influence the prognosis. The aim of the present study was to analyze the different staging modalities used among patients with a diagnosis of primary oral squamous cell carcinoma between 2008 and 2015. MATERIAL AND METHODS: An analysis of preoperative staging findings, collected by clinical palpation, ultrasound, and computed tomography (CT), was performed. The results obtained were compared with the results of the final histopathological findings of the neck dissection specimens. A statistical analysis using McNemar's test was performed. RESULTS: The sensitivity of CT for the detection of malignant cervical tumor spread was 74.5%. The ultrasound obtained a sensitivity of 60.8%. Both CT and ultrasound demonstrated significantly enhanced sensitivity compared to the clinical palpation with a sensitivity of 37.1%. No significant difference was observed between CT and ultrasound. A combination of different staging modalities increased the sensitivity significantly compared with ultrasound staging alone. No significant difference in sensitivity was found between the combined use of different staging modalities and CT staging alone. The highest sensitivity, of 80.0%, was obtained by a combination of all three staging modalities: clinical palpation, ultrasound and CT. CONCLUSIONS: The present study indicates that CT has an essential role in the preoperative staging of patients with oral squamous cell carcinoma. Its use not only significantly increases the sensitivity of cervical lymph node metastasis detection but also offers a preoperative assessment of local tumor spread and resection borders. An additional non-invasive cervical lymph node examination increases the sensitivity of the tumor staging process and reduces the risk of occult metastasis.

Lethal cervical abscess following bisphosphonate related osteonecrosis of the jaw.

CONTEXT: Bisphosphonates are common drugs used in the management of bone metabolic diseases. Because of their recently increased use, their adverse effects, especially bisphosphonate-related osteonecrosis of the jaw (BRONJ), are monitored more frequently. BRONJ is a critical challenge in craniofacial surgery and is difficult to treat. Its occurrence is either spontaneous or follows dentoalveolar surgery. Typical complications of BRONJ are painful exposed bone, pathological fractures, extra-oral fistula, and local infections. OBJECTIVE: The aim of this paper is to report a rare case of bacterial embolism in the internal jugular vein after a BRONJ-induced submandibular abscess resulting in bacterial sepsis, multi-organ failure syndrome, and death. CASE ILLUSTRATION: A 59-year-old female patient developed severe BRONJ (stage II) with recurrent abscesses after oral osteoporosis therapy with alendronic acid. A subsequent submandibular abscess led to bacterial embolism of the left internal jugular vein, causing sepsis and death. DISCUSSION: Prevention, early detection and management of BRONJ remain a crucial challenge in craniofacial clinical practice. Despite several therapeutic approaches described in the current literature, none have undergone bedside application. CONCLUSION: Considering this report of death after recurrent abscesses following BRONJ, the use of bisphosphonates should be carefully monitored in order to prevent such severe complications.

Nonsynostotic cranial deformity: a six-month matched-pair photogrammetric comparison of treated and untreated infants.

Objective : To photogrammetrically objectify changes in nonsynostotic craniofacial deformity in orthotically treated versus untreated infants. Design : A statistical retrospective pairwise comparison of two respective three-dimensional (3D) photo scans of 80 children performed in a 6-month time lag. Patients : Two comparable samples of children (40 treated, 40 untreated) with nonsynostotic cranial deformity. Interventions : Respective 3D photo scans were matched using Cranioform Analytics 4.0 software. Main Outcome Measures : Median change of 30° Cranial Vault Asymmetry Index (CVAI), modified CVAI (CVAImod), Cranial Index (CI), and posterior symmetry ratio (PSR). Results : We found an improvement in Δ30° CVAI by 3.3% (treated) and by 1.31% (untreated), respectively. CVAImod improved by 3.46% in the treated group and by 1.55% in the untreated group. CI improved by 4.41% in the treated group and by 3.68% in the untreated group, and PSR improved by 0.71 in the treated group and 0.49 in the untreated group. Although improvement of cranial asymmetry was higher in those children treated with an individual molding orthosis, we could not document a statistically significant difference between the two groups. Conclusions : Helmet therapy may be less appropriate for the correction of brachycephaly than for cranial asymmetry. Nonsynostotic cranial deformity shows some spontaneous correction. Photogrammetry presents an accurate method to objectify craniofacial changes in early infancy.

Reduced platelet aggregation in a boy with scurvy.

Pediatric scurvy is a rare condition characterized by perifollicular petechiae and bruising, hemorrhagic gingivitis and musculoskeletal symptoms, all assumed to be predominantly related to abnormal collagen structure. We report on a 9-year-old autistic boy with vitamin C deficiency due to a highly limited food range presenting with multiple petechiae, gum bleeding and debilitating bone pain, in whom platelet aggregometry revealed a distinctly reduced thrombocyte aggregation, normalizing after vitamin C supplementation. This observation indicates that platelet dysfunction may additionally contribute to the hemorrhagic diathesis in scurvy, and demonstrates that ascorbic acid deficiency should be considered in children with an otherwise unexplained acquired thrombocytopathy.

Non-linear 3D evaluation of different oral implant-abutment connections.

Micro-gaps and osseous overload in the implant-abutment connection are the most common causes of peri-implant bone resorption and implant failure. These undesirable events can be visualized on standardized three-dimensional finite element models and by radiographic methods. The present study investigated the influence of 7 available implant systems (Ankylos, Astra, Bego, Brånemark, Camlog, Straumann, and Xive) with different implant-abutment connections on bone overload and the appearance of micro-gaps in vitro. The individual geometries of the implants were transferred to three-dimensional finite element models. In a non-linear analysis considering the pre-loading of the occlusion screw, friction between the implant and abutment, the influence of the cone angle on bone strain, and the appearance of micro-gaps were determined. Increased bone strains were correlated with small (< 15°) cone angles. Conical implant-abutment connections efficiently avoided micro-gaps but had a negative effect on peri-implant bone strain. Bone strain was reduced in implants with greater wall thickness (Ankylos) or a smaller cone angle (Bego). The results of our in silico study provide a solid basis for the reduction of peri-implant bone strain and micro-gaps in the implant-abutment connection to improve long-term stability.

Accuracy of three-dimensional photogrammetric images in non-synostotic cranial deformities.

OBJECTIVE: Given the increasing incidence of deformational plagiocephaly due to infants' supine sleeping position to prevent sudden infant death syndrome, reliable anthropometric diagnostics are needed. Besides the traditional method of measuring landmarks with callipers, three-dimensional (3D) photography has great potential. In this investigation the accuracy of 3D photogrammetry is studied. METHODS: The study included 100 randomly chosen children between the ages of 4 and 20 months with a non-synostotic cranial deformity in a retrospective analysis. Measurements of diagonals A and B on the infant's head were obtained once using callipers. 3D photographs of these children were measured 5 times by 5 clinicians separately. RESULTS: The inter- and intra-rater agreements of the 3D measurements had low variability in the variance component analysis. The standard deviations for reproducibility and repeatability were 0.117-0.283 cm for diagonals A and B. The intra-class correlation coefficients for the inter-rater reliability resulted in excellent agreement (0.97 for plagiocephaly, 0.98 for brachycephaly, 0.96 for combined deformity). The comparison of the 3D photographic and callipers measurements showed that 3D photography resulted in a slight over-estimation. CONCLUSION: 3D photogrammetry is potentially a reliable tool for treatment planning and follow-up of abnormal head shapes in infancy.