Comparison of Biological Characteristics of Different Paranasal Sinus Mucosa in Goats.

BACKGROUND/PURPOSE: Prosthetic implants are the primary treatment for patients with edentulism. This study aims to explore and compare the biological characteristics of mucosal thickness and tensile strength of the paranasal sinuses (maxillary and frontal sinuses) in goats, thereby providing a theoretical basis and guidance for mucosa-related problems involved in maxillary sinus lifting. MATERIALS AND METHODS: The paranasal sinus mucosa (maxillary sinus crest, maxillary sinus floor and frontal sinus mucosa) was obtained from the goats for use in maxillary sinus lifting. The mucosa was made into tissue section specimens and evaluated by a computer with built-in screenshot software and an optical microscope with a graduated eyepiece. A total of 3 readings were randomly selected and recorded. The mucosa was clamped with a laboratory-made clamp device. After connecting the push-pull meter, the mucosa exposed by the inner ring of the clamp device was pressed vertically and uniformly until it ruptured. The strength value was read and recorded. The left and right ends of the mucosa were connected with the clamp device; horizontal tension was applied evenly to the mucosa until the mucosa ruptured. The strength value was read and recorded. The normality test, analysis of variance, LSD pairwise comparison and linear regression were performed for each group of data. RESULTS: The thicknesses of the maxillary sinus crest mucosa, floor mucosa and frontal sinus mucosa in goats were 410.03 ± 65.97 um, 461.33 ± 91.37 um and 216.90 ± 46.47 um, respectively. There were significant differences between the maxillary sinus crest and frontal sinus and the maxillary sinus floor and frontal sinus (P < .05). The range of tensile strength of the maxillary sinus crest mucosa, floor mucosa and frontal sinus mucosa in goats was 0.48 ± 0.10 kg, 0.54 ± 0.11kg and 0.20 ± 0.05kg, respectively. There were significant differences between the maxillary sinus crest and frontal sinus and the maxillary sinus floor and frontal sinus (P < .05). Tensile strength was positively correlated with the thickness of the mucosa of the maxillary and frontal sinuses (P < .05). CONCLUSION: The mucosal thickness and tensile strength of the maxillary sinus crest and floor were greater than those of the frontal sinus mucosa. There was a positive correlation between the tensile strength and the thickness of the mucosa.

Comparison of biological and mechanical properties of different paranasal sinus mucosa in goat.

OBJECTIVE: The present study was designed to explore endurable pressure intensity of different paranasal sinus mucosa in goats. METHOD: Mucosa commonly involved in maxillary sinus augmentation, including mucosa from maxillary sinus crest, maxillary sinus floor, and frontal sinus, were harvested in a computed tomography-guided manner. The obtained mucosa was then sectioned into square and irregular ones for maximum endurable pressure intensity determination and morphological observation, respectively. RESULTS: Thickness of paranasal sinus mucosa, as determined under morphological staining by an optical microscope with a graduated eyepiece, were calculated. And the results showed that the average thickness of maxillary sinus crest mucosa, floor mucosa, and frontal sinus mucosa in goats were 410.03 ± 65.97 µm, 461.33 ± 91.37 µm and 216.90 ± 46.47 µm, respectively. Significant differences between maxillary sinus crest and frontal sinus, maxillary sinus floor, and frontal sinus were observed (P < 0.05). Maximum endurable pressure intensity was determined by utilizing a self-made clamp device and the results revealed maximum endurable pressure intensity of maxillary sinus crest mucosa, floor mucosa and frontal sinus mucosa in goats were 260.08 ± 80.12Kpa, 306.90 ± 94.37Kpa and 121.72 ± 31.72Kpa, respectively. Also, a statistically significant difference was observed when comparing the endurable pressure intensity between maxillary sinus crest and frontal sinus, maxillary sinus floor, and frontal sinus (P < 0.05). Further correlation analysis also revealed a positive correlation between the thickness of mucosa of the maxillary sinus and frontal sinus and maximum endurable pressure intensity (P < 0.05). CONCLUSION: Mucosal thickness and maximum endurable pressure intensity of maxillary sinus crest and floor were larger than that of frontal sinus mucosa and a positive correlation between the thickness of mucosa and endurable pressure intensity was observed. Our results thus might provide an experimental basis and guidance for mucosa-related problems involved maxillary sinus augmentation.

Design of Complete Dentures by Adopting CAD Developed for Fixed Prostheses.

The demand for complete dentures is expected to increase worldwide, but complete dentures are mainly designed and fabricated manually involving a broad series of clinical and laboratory procedures. Therefore, the quality of complete dentures largely depends on the skills of the dentist and technician, leading to difficulty in quality control. Computer-aided design and manufacturing (CAD/CAM) has been used to design and fabricate various dental restorations including dental inlays, veneers, crowns, partial crowns, and fixed partial dentures (FPDs). It has been envisioned that the application of CAD/CAM technology could reduce intensive clinical/laboratory work for the fabrication of complete dentures; however, CAD/CAM is seldom used to fabricate complete dentures due to the lack of suitable CAD software to design virtual complete dentures although the CAM techniques are in a much advanced stage. Here we report the successful design of virtual complete dentures using CAD software of 3Shape Dental System 2012, which was developed for designing fixed prostheses instead of complete dentures. Our results demonstrated that complete dentures could be successfully designed by the combination of two modeling processes, single coping and full anatomical FPD, available in the 3Shape Dental System 2012.

Feasibility of Shape-Memory Ni/Ti Alloy Wire Containing Tube Elevators for Transcrestal Detaching Maxillary Sinus Mucosa: Ex Vivo Study.

BACKGROUND: Osteotome sinus floor elevation is a less invasive approach to augment an insufficient alveolar bone at the posterior maxilla for dental implantation. However, this approach has some limitations due to the lack of sinus lift tools available for clinical use and the small transcrestal access to the maxillary sinus floor. We recently invented shape-memory Ni/Ti alloy wire containing tube elevators for transcrestal detaching maxillary sinus mucosa, and developed goat ex vivo models for direct visualizing the effectiveness of detaching sinus mucosa in real time during transcrestal maxillary sinus floor elevation. METHODS: We evaluated our invented elevators, namely elevator 012 and elevator 014, for their effectiveness for transcrestal detaching maxillary sinus mucosa using the goat ex vivo models. We measured the length of sinus mucosa detached in mesial and distal directions or buccal and palatal directions, and the space volume created by detaching maxillary sinus mucosa in mesial, distal, buccal and palatal directions using the invented elevators. RESULTS: Elevator 012 had a shape-memory Ni/Ti alloy wire with a diameter of 0.012 inch, while elevator 014 had its shape-memory Ni/Ti alloy wire with a diameter of 0.014 inch. Elevator 012 could detach the goat maxillary sinus mucosa in the mesial or distal direction for 12.1±4.3 mm, while in the buccal or palatal direction for 12.5±6.7 mm. The elevator 014 could detach the goat maxillary sinus mucosa for 23.0±4.9 mm in the mesial or distal direction, and for 19.0±8.1 mm in the buccal or palatal direction. An average space volume of 1.7936±0.2079 ml was created after detaching the goat maxillay sinus mucosa in both mesial/distal direction and buccal/palatal direction using elevator 012; while the average space volume created using elevator 014 was 1.8764±0.2366 ml. CONCLUSION: Both two newly invented tube elevators could effectively detach the maxillary sinus mucosa on the goat ex vivo sinus models. Moreover, elevator 014 has advantages over the elevator 012 for the capability to detach sinus mucosa.

Ex vivo comparative study on three sinus lift tools for transcrestal detaching maxillary sinus mucosa.

The objective of this study was to comparatively evaluate 3 different sinus lift tools, namely umbrella-shaped sinus lift curette YSL-04, our recently designed probe-improved sinus lift curettes, and our newly invented elevator 014, using our previous developed goat ex vivo models for direct visualizing the effectiveness of detaching sinus mucosa in real time. Goat ex vivo models for direct visualizing the effectiveness of detaching sinus mucosa in real time were generated according to our previously developed protocol. The effectiveness for each tool was evaluated through the length of sinus mucosa detached in mesial and distal directions or buccal and palatal directions, and the space volume created by detaching maxillary sinus mucosa in mesial, distal, buccal and palatal directions. The results showed that all 3 sinus lift tools could transcrestally detach the maxillary sinus mucosa and create extra space under the elevated sinus floor on the goat ex vivo sinus models. Moreover, our newly invented elevator 014 had advantages over the other 2 in term of the capability to detach the sinus mucosa. Our newly invented elevator 014 might be a promising tool for detaching maxillary sinus mucosa in transcrestal maxillary sinus floor elevation.

[Comparative study on bilateral temporomandibular joint of patients with unilateral multiple symptoms in cone-beam computed tomography].

PURPOSE: To investigate bilateral temporomandibular joint of patients with unilateral multiple symptoms in cone-beam computed tomography (CBCT) and explore the reference planes that may be different,providing reference for the diagnosis of temporomandibular disorders and comparative study. METHODS: 50 cases with unilateral multiple symptoms（except for cases with unilateral single symptom）were examined by CBCT and the following indexes were observed and analyzed,including horizontal angles of the cross-sectional condyle after the reconstruction in the same patient, joint space, macroaxis diameter of condyle and vertical angles of condyle, which were commonly used at oblique position parallelled to the long axis of condyle, the gradient of articular tubercle and the joint space,which could be obtained at sagittal and oblique position vertical to the long axis of condyle.The data obtained was analyzed by paired t test with SPSS13.0 software package. RESULTS: There was significant difference between the bilateral measured value of joint space when the angle was 60° in sagittal plane (P<0.05).The difference was more significant when the angle was 120° in parallel plane and 90° in sagittal plane (P<0.01). The other measured parameters were not significant different. CONCLUSIONS: For patients with TMD, it is more easily to observe differences between the bilateral measured value of joint space in the sagittal or vertical plane,where the increase of the front joint space can be seen and construction was more significant.