Calculation of postoperative bone healing of cystic lesions of the jaw-a retrospective study.

OBJECTIVES: There is a long history of studies into cystic lesions of the jaws. However, there is little data on postoperative bone regeneration. The aim of the study was to calculate the size of the residual bone lesions after cystostomies and cystectomies to predict the postoperative bone healing. MATERIAL AND METHODS: This retrospective study focused on patients undergoing cystectomy (n = 114) or cystostomy (n = 86), who were treated for cystic lesions between 2010 and 2015. New formulas were developed to measure the decrease in lesion sizes using the craniocaudal and mesiodistal diameters from preoperative as well as postoperative radiographs (panoramic radiographs, CT scans, CBCT). With these predictive models (calculated by linear regression analyses), it is possible to calculate how the lesions would shrink using initial size of the cyst and time after surgery for both dimensions. RESULTS: After cystostomy, the mesiodistal size was initial size 6.0 + 0.7 × initial size - 9.4 × time. The craniocaudal size was 5.1 + 0.7 × initial size - 7.3 × time. After cystectomy, the mesiodistal size was 0.4 + 0.7 × initial size - 8.4 × time. The craniocaudal size was 0.4 + 0.5 × initial size - 6.4 × time (R2 = 0.59 and 0.67, respectively). CONCLUSION: These formulas are suggested to be used to calculate residual size of bone lesion after cystostomy and cystectomy to predict postoperative bone healing. CLINICAL RELEVANCE: The formulas are based on deliberately simple measurement using only panoramic radiographs to encourage their application in daily clinical practice.

Fiber-Reinforced Resin Fixed Prostheses on 4 Short Implants in Severely Atrophic Maxillas: 1-Year Results of a Prospective Cohort Study.

PURPOSE: The aim of this study was to report on 1-year outcomes of fixed full-arch fiber-reinforced resin bridges on short implants in atrophic maxillary jaws. MATERIALS AND METHODS: A prospective cohort study was designed and patients with severely atrophic maxillas, corresponding to Cawood and Howell Classes V and VI, were included. Mesial and distal peri-implant bone levels were assessed on panoramic radiographs that were taken at the time of implant insertion (baseline) and during follow-up visits. RESULTS: Eighteen patients with 72 implants inserted in atrophic maxillary jaws were included in this study. All patients had a follow-up visit 1 year after loading. The cumulative 1-year patient-based implant survival rate was 88.8%, and the cumulative 1-year implant-based survival rate was 97.2%. The marginal bone level (MBL) was -0.5 ± 0.5 mm at the time of loading (n = 72) and -0.8 ± 0.6 mm (n = 72) after 1 year. The MBL depended substantially on the depth at the time of insertion. No prosthetic failure, such as chipping or fracture, occurred within the first year of loading. CONCLUSION: Prosthetic rehabilitation of atrophic maxillas with prostheses supported by 4 4.0- × 5.0-mm or 3.0- × 8.0-mm implants seems to be a viable and cost-effective treatment option in the short-term.

Fixed, Fiber-Reinforced Resin Bridges on 5.0-mm Implants in Severely Atrophic Mandibles: Up to 5 Years' Follow-Up of a Prospective Cohort Study.

PURPOSE: The aim of this study was to evaluate the midterm outcomes of fixed, full-arch, fiber-reinforced resin bridges on ultrashort implants in terms of marginal bone loss and overall implant survival. PATIENTS AND METHODS: Patients with severely atrophic mandibles, corresponding to Cawood and Howell class V and class VI, were included in this prospective temporal cohort study. Mesial and distal peri-implant bone levels were measured on panoramic radiographs taken at the time of implant insertion (baseline) and at follow-up visits. RESULTS: A total of 17 patients with atrophic mandibular jaws with an average follow-up period of 2.9 ± 1.5 years were included. The cumulative 1-, 3-, and 5-year patient-based implant survival rates were 94.1%, and the cumulative implant survival rates were 98.5%. The marginal bone level (MBL) of the mesial implants was 0.0 ± 0.3 mm at the time of loading (n = 33), -0.1 ± 0.3 mm (n = 20) after 1 year, -0.4 ± 0.5 mm (n = 10) after 3 years, and -1.5 ± 1.0 mm (n = 4) after 5 years. The mesial bone level depended significantly on time and insertion depth. The MBL of the distal implants was -0.4 ± 0.4 mm (n = 34) at the time of implantation, -0.4 ± 0.6 mm (n = 20) after 1 year, -0.5 ± 0.5 mm (n = 10) after 3 years, and -2.2 ± 1.7 mm (n = 4) after 5 years. The distal bone level depended significantly on time and insertion depth. CONCLUSIONS: Fixed, full-arch, fiber-reinforced resin bridges retained by 4 ultrashort implants provide a comparatively cost-effective, safe, stable alternative for prosthetic restoration of the severely atrophic mandible. The overall implant survival rate and the MBL after 5 years are equivalent to those of threaded implants of conventional lengths.

Soft Tissue Changes in Patients Undergoing Intraoral Quadrangular Le Fort II Osteotomy Versus Conventional Le Fort I Osteotomy.

PURPOSE: The aim of this study was to evaluate soft tissue changes after intraoral quadrangular Le Fort II osteotomy (IOQLFII) and correlate those changes to underlying osseous changes. MATERIALS AND METHODS: Twenty-six non-growing patients with midfacial deficiency and Class III malocclusion were analyzed. A study group of 13 patients who underwent IOQLFII was compared with 13 patients who underwent conventional Le Fort I osteotomy (LFI). After fusion of pre- and postoperative computed tomograms, each patient's hard and corresponding soft tissue changes were measured. Measurement points were defined at 3 levels in the IOQLFII group (infraorbital rim [IR], sinus floor [SF], and lateral incisor tip [LI]) and at 2 levels in the LFI group (SF and LI). Linear models were created to test for correlations between hard and soft tissues. RESULTS: The slope (a1 coefficient) between anteroposterior hard and soft tissue changes was found to be highly significant at each measurement point for all groups. In the IOQLFII group, soft tissue advancement was 69% (confidence interval [CI], 62 to 77%) of the hard tissue advancement at the IR, 90% (CI, 84 to 96%) at the SF, and 73% (CI, 64 to 82%) at the LI. In the LFI group, the corresponding percentages were 90% (83 to 97%) at SF and 84% (77 to 90%) at LI. CONCLUSION: IOQLFII results in predictable correction of midfacial deficiency. At the IR, bony advancement always resulted in markedly less soft tissue advancement than at the SF level. These results indicate that the planned infraorbital advancement should not be too conservative because soft tissue changes are smaller in this region.

Biliary metal stents for proximal esophageal or hypopharyngeal strictures.

INTRODUCTION: Endoscopic dilation is the standard of care for stenoses of the cervical esophagus, but refractory strictures require some form of stenting. Most endoscopists avoid the placement of metal stents near the upper esophageal sphincter as they can cause major problems like severe cervical pain and globus sensation. We report our results with the use of biliary SEMS in the upper esophagus, which have a smaller diameter than regular esophageal stents and therefore exert less expansive force. MATERIAL AND METHODS: We retrospectively reviewed all patients in our center between July 2011 and June 2014 who received a biliary metal stent because of a refractory stricture in the cervical esophagus. We implanted biliary SEMS (Wallflex, Boston Scientific) with a diameter of 1 cm and length of 6-8 cm. Technical and clinical success, adverse events and duration of stenting were evaluated. RESULTS: Ten patients were treated with biliary SEMS in the upper esophagus. Strictures were located between 10 and 19 cm from incisor teeth. Stent placement was successful in all (10/10) patients. One stent had to be extracted because of pain and globus sensation. Apart from that stent tolerability was good. All remaining patients (9/9) reported improvement of dysphagia with a decrease in mean dysphagia score from 3.2 to 1.78. Mean duration of stenting was 68 days. DISCUSSION: Because of a high clinical success rate and good tolerability, biliary metal stents are a reasonable alternative for difficult strictures in the cervical esophagus, especially in the palliative setting.

Palatal sinus elevation revisited: a technical note.

The palatal sinus lift is a good choice for patients with scarred buccal soft tissue and those with poor wound healing such as smokers or diabetics or when visual side effects such as swelling must be concealed. We provide a surgical protocol for palatal sinus lifting without a vertical release incision. The incision is started in a slightly palatal aspect, at the distal end of the dental arch, and describes a curve laterally on the alveolar crest while running in a mesial direction. As a marginal incision, it can continue to the central incisor. Submucosal exposure will lift the gum and the greater palatine artery. After insertion of a tongue depressor, the sinus is opened on the palatal side, opposite the zygomaticoalveolar crest, using a rose bur or a piezotome. After sinus augmentation, the incision is easy to close, and the wound will heal smoothly.

Bone formation after surgically assisted rapid maxillary expansion: comparison of 2 distraction osteogenesis protocols.

OBJECTIVE: The aim of this study was to compare bone formation between 2 distraction osteogenesis protocols by analyzing cone beam computed tomography (CBCT) scan data. STUDY DESIGN: In this retrospective study, the efficacy of 2 different surgically assisted rapid maxillary expansion protocols (group 1 [G1], 3 × 0.25 mm/d; group 2 [G2], 1 mm start followed by 2 × 0.25 mm/d) was analyzed using CBCT scans obtained at 3 time points: preoperatively (T0), immediately after surgery (T1), and 6 months after surgery (T2). Bone formation at T0, T1, and T2 was analyzed using the Dolphin Imaging 11 program. RESULTS: At T1, both groups had significantly higher bone volume than at T0 (G1, 135.6 vs 124.65 mm3, respectively; G2, 153.49 vs 118.9 mm3, respectively), with no significant difference between groups (P = .6). Moreover, bone density measured in the region of interest was similar between groups at all 3 time points; however, in both groups, bone density was significantly lower at T1 and T2 than at T0 (P < .01), with no difference between T1 and T2. CONCLUSIONS: Bone density between the incisors decreased with progressive distraction (i.e., increasing volume), regardless of the distraction protocol used; thus, both protocols can be used safely in clinical practice. Nevertheless, our results indicate that stress should not be applied to the incisors within 6 months of surgery, regardless of the protocol used. Surgeons and orthodontists should therefore consider immature bone formation and avoid using excessive force to close a diastema.

Quantifying the environmental impact of clustering strategies in waste management: A case study for plastic recycling from large household appliances.

The complex composition of waste electrical and electronic equipment (WEEE) plastics represents a challenge during post-consumption plastic recycling. A single WEEE category, e.g. large household appliances (LHA), can contain several different plastic types with overlapping material properties, making the sorting of individual plastics a challenge. Significant increases in plastic recovery rates can be expected by clustering product categories, as clustering can avoid mixing of non-compatible plastics with overlapping material properties. For this purpose, a life cycle assessment (LCA) is conducted to investigate the influence of different clustering strategies on the environmental performance of waste treatment and the production of recycled plastic from LHA waste stream. To assure comparability between waste treatment scenarios a system expansion approach is applied, and to allocate the burden of shared processes over the first and second use cycle of the material partitioning is applied. Results show that an increased separation of product clusters by plastic type can improve the plastic recovery rate from 5.8% to 47.1% and reduce the overall environmental impact, quantified with the ReCiPe (2016) method, by up to 23%. The environmental impacts of using recycled plastics from LHA waste can be reduced by 27 to 38% compared to single-use plastic. The holistic approach used in this study demonstrates (1) the potential benefits of implementing product clustering strategies for LHA plastic recycling, (2) the relevance of different allocation procedures when integrating recycling into an LCA, (3) the importance of using less virgin material and avoiding final waste treatment, and (4) the limitation of the recycling system to reduce the environmental burden associated with products.

Changes of temporomandibular joint position after surgery first orthognathic treatment concept.

Orthognathic surgery treatment (OGS) after orthodontic treatment of dentofacial deformities is a widely performed procedure, often accompanied by a bilateral sagittal split osteotomy (BSSO). Positioning of the condyle during this procedure is a crucial step for achieving optimal functional and anatomical results. Intraoperatively poorly positioned condyles can have a negative effect on the postoperative result and the patient's well-being. Changes of the condylar position during OGS Procedures and its effects on the temporomandibular joint in orthognathic surgical interventions (OGS) are subject of scientific discussions. However, up to date, no study has investigated the role of condyle position in the surgery first treatment concept. The aim of this study was to investigate the influence of OGS on the three-dimensional position of the condyle in the joint in a surgery first treatment concept without positioning device and to record the change in position quantitatively and qualitatively. Analysis of our data indicated that OGS in surgery first treatment concept has no significant effect on the position of the condyle and the anatomy of the temporomandibular joint.

What do sales data tell us about implant survival?

OBJECTIVE: The aim of this study was to evaluate the influence of implant diameter, length and shape on a surrogate parameter of implant survival; i.e. the implant return rate in a big data analysis. MATERIALS AND METHODS: A retrospective study was conducted and the factors influencing the success rates of 69,377 sold implants over a seven-year period were evaluated. The osseointegration program of a reseller provides reliable data of a single country. Implant loss rates were investigated using logistic regression models and regressed by implant type, diameter, and length. RESULTS: The return rate of 69,377 sold implants was 2.78% and comparable to implant loss rates in previous published prospective studies as its surrogate parameter. A total of 80% of implant returns had occurred within 157 days, and an additional 15% within 750.25 days. Diameters of 3.8 to 5.0mm showed the lowest return rates with its bottom in the 4.3mm implant whilst 6.0mm implants had significantly higher return rates. In comparison to the most sold implant length (13mm) shorter implants showed significantly higher early return rates. CONCLUSIONS: The study provides evidence that in cases of standard indications and sufficient bone, the use of screw typed dental implants with 3.8 or 4.3 diameter and 11 or 13 mm length shows the lowest implant return rates. Other implants may be selected only in specific indications.

Evaluation of an experimental oblique plate for osteosynthesis of mandibular condyle fractures.

OBJECTIVE: The aim of this study was to test the bone thickness and potential screw length for osteosynthesis of condylar base fractures (according to the Loukota classification) with an experimental titanium plate, placed in an ideal position against 2 types of conventional plates. STUDY DESIGN: After exclusion of completely edentulous mandibles, 28 dentate macerated mandibles available at the time of the study were included. Linear regression models 1 and 2 compared the sums of the 2 cranial bone thicknesses and the 3 caudal thicknesses among the 3 different plate designs, and linear models 3 and 4 tested the bone thickness in the 2 most cranial screw axes. RESULTS: Linear models 1 and 2 revealed significantly higher potential screw lengths for the experimental oblique plate. Equally, linear models 3 and 4 indicated significantly higher bone thickness for the novel oblique plate. CONCLUSION: The novel proposed oblique plate allows for favorable plate positioning in a biomechanically ideal location with sufficient amounts of local bone for stable plate fixation. When plates with 15-degree angulated screw holes are used, stable bicortical plate fixation can be achieved.

Does osteoporosis influence the marginal peri-implant bone level in female patients? A cross-sectional study in a matched collective.

BACKGROUND/PURPOSE: Osteoporosis, being a homeostatic imbalance, affects the remodeling of bone. Whether this catabolic bone disease influences peri-implant marginal bone remodeling remains unknown so far. The purpose of this study was to evaluate the influence of osteoporosis on peri-implant marginal bone loss (MBL) in postmenopausal women. MATERIALS AND METHODS: In a matched collective, radiographic peri-implant bone level (at baseline and at follow-up examinations) was compared in healthy and osteoporotic women. General health and behavioral history of the patients were recorded using a printed questionnaire. RESULTS: A best fit matching procedure generated a sample of 48 women with a total of 204 implants matched at patient and implant level that was further statistically analyzed. The mean mesial MBL-statistically corrected to report the first year-was -0.6 ± 1.2 mm (range: -5.1 to 2.2) in the healthy control group and -1.1 ± 1.3 mm (range: -5.3 to 2.2) in the osteoporotic group. Similarly, the mean distal MBL was -0.5 ± 1.3 mm (range: -5.1 to 4.8) in the healthy control group and -1.2 ± 1.3 mm (range: -4.7 to 1.6) in the osteoporotic group, respectively. The base linear regression models including solely osteoporosis and time without any other confounders revealed a significant influence of osteoporosis and time since implant placement on the MBL at the mesial and the distal implant aspect. The significance of osteoporosis on bone loss did not change incorporating the confounders: bone level at implantation, smoking, jaw, location, surface, concrement, plaque, augmentation, edentulism in opposing and implant jaw, bisphosphonates, vitamin D, fixed versus removable prosthetics, connection type. CONCLUSIONS: There is no contraindication to place dental implants in osteoporotic patients. This study implicates to respect the bone level at implant placement and not to place the implant below bone level if possible.

Morphometric analysis of sinus depth in the posterior maxilla and proposal of a novel classification.

The aim of this study was to analyse the posterior maxillary sinus based on its extension into the alveolar process and to provide a simple clinical classification. A retrospective cohort study was conducted in CT scans of 200 dentate and 200 edentulous patients (100 women and 100 men, respectively). After manual placement of 12 reference points morphometric analysis was performed and sinus depth, residual alveolar ridge height (RH) and the sinus opening angle were calculated. Sinuses were classified according to the quartiles of sinus depth: class I (above the hard palate), class II (0-6 mm below the hard palate) and class III (>6 mm below the hard palate). Sinus depth was found to be a reliable anatomical landmark and did not vary significantly between gender (p = 0.8940) or dentition groups (p = 0.9723). Alveolar height varied significantly between sinus classes (p < 2 × 10-16) and dentition groups (p < 2 × 10-16) but not between genders (p = 0.5178). The sinus opening angle was significantly different between sinus classes (p < 2.2 × 10-16) but not between gender or dentition groups. We propose a novel classification built upon the quartiles of sinus depth, dividing the sinuses into three classes. Our classification is the first one that represents the anatomy of the patient independent of gender and dentition.

Natural polymer-stabilized multiple water-in-oil-in-water emulsions: a novel dermal drug delivery system for 5-fluorouracil.

OBJECTIVES: The aim of this study was to create multiple water-in-oil-in-water (W/O/W) emulsions with an increased long-term stability as skin delivery systems for the hydrophilic model drug 5-fluorouracil. METHODS: Multiple W/O/W emulsions were prepared in a one-step emulsification process, and were characterized regarding particle size, microstructure and viscosity. In-vitro studies on porcine skin with Franz-type diffusion cells, tape stripping experiments and attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR) were performed. KEY FINDINGS: The addition of Solagum AX, a natural polymer mixture of acacia and xanthan gum, led to multiple W/O/W emulsions with a remarkably increased long-term stability in comparison to formulations without a thickener. The higher skin diffusion of 5-fluorouracil from the multiple emulsions compared with an O/W-macroemulsion could be explained by ATR-FTIR. Shifts to higher wave numbers and increase of peak areas of the asymmetric and symmetric CH2 stretching vibrations confirmed a transition of parts of the skin lipids from an ordered to a disordered state after impregnation of porcine skin with the multiple emulsions. CONCLUSIONS: Solagum AX is highly suitable for stabilization of the created multiple emulsions. Moreover, these formulations showed superiority over a simple O/W-macroemulsion regarding skin permeation and penetration of 5-fluorouracil.