Chapter 4 Flashcards
Stress Treatment Theorem for Implant Dentistry
Which of the following statements is false:
A) Biological factors play a greater role in tooth-supported prostheses complications
B) Biomechanical factors play a greater role in implant supported prostheses complications
C) Implant failures usually arise within 9 months of being loaded
D) Implants form a successful interface >95% of the time
C - A literature review focusing on implant failure indicated these problems primarily occur within 18 months of initial implant loading. These early implant loading failures occur most often in the softest bone types (16% failure) or the shortest implant lengths (17% failure)
Reasons for surgical failure of an implant include everything BUT:
A) Over-torquing a tapered screw-type implant during insertion
B) Excessive heat during osteotomy preparation
C) Excessive pressure during insertion
D) Micromovement
D - Brunski observed a fibrous tissue interface development when a dental implant moved more than 100 microns during initial healing.
Which is the correct order for most likely to experience screw loosening to least likely:
A) Single-implant > Multiple-unit fixed prostheses > Implant overdentures
B) Implant overdentures > Multiple-unit fixed prostheses > Single-implant
C) Single-implant > Implant overdentures > Multiple-unit fixed prostheses
D) Implant overdentures > Single-implant > Multiple-unit fixed prostheses
A - Single-tooth crowns exhibited the highest rate of 25% in early screw designs and concepts (and as high as 45%).
Recent studies indicate this ratio has been reduced to an overall 8% average, with multiple-unit fixed prostheses at a 5% average and implant overdentures at 3%
Adell et al report the average marginal bone loss in the first 12 months is
A) 1.2mm from the first thread
B) 1.8mm from the first thread
C) 3.3mm from the first thread
D) 1.2mm from the original crestal bone level
A - Adell et al. were the first to quantify and report marginal bone loss. The study also indicated greater magnitude and occurrence of bone loss during the first year of prosthesis loading, averaging 1.2 mm during this time frame, with a range of 0 to 3 mm. This report measured bone loss from the first thread as the 0-mm baseline, not from the original level of crestal bone at insertion, which was 1.8 mm above this baseline point. Thus the actual first-year crestal bone loss averaged 3.3 mm around the implants observed
Which of the following statements is true for long bones of the body:
A) 57% of the arterial supply and 100% of the venous return for long bones comes from the periosteum
B) 100% of the arterial supply and 57% of the venous return for long bones comes from the periosteum
C) 100% of the arterial supply and 90% of the venous return for long bones comes from the periosteum
D) 90% of the arterial supply and 100% of the venous return for long bones comes from the periosteum
D - Ninety percent of the arterial blood supply and 100% of the venous return are associated with the periosteum in the long bones of the body
Which of the following statements is false:
A) A smooth 4-mm collar below the bone is associated with more bone loss than a 2-mm collar
B) Biological width theory cannot explain the total vertical bone loss
C) Bone loss from biological width occurs within 3 months, regardless of loading or not
D) Biological bone loss is not related to the density of bone
C - A smooth polished 4-mm collar below the bone has been associated with greater bone loss than a smooth 2-mm collar below the bone. The implant biological width concept does not explain completely the total amount of vertical bone loss observed. In addition, the amount of bone loss from the biological width occurs within 1 month, whether the implant is loaded or not, and is related to the crest module implant design and the position of the abutment-implant connection in relation to the bone but is unrelated to the density of the bone.
Strain is: A) What you are feeling about now B) Change in length divided by original length C) Force divided by surface area D) Force x surface area
B - Bone remodeling at the cellular level is controlled by the mechanical environment of strain. Strain is defined as the change in length divided by the original length, and the units of strain are given in percentages. The amount of strain in a material is directly related to the amount of stress applied
Appleton et al demonstrated progressively loaded single-tooth implants:
A) Have less bone loss and greater bone density increases in the crestal half
B) Never vote conservative
C) Have more marginal bone loss than other implants
D) Have less bone loss and greater bone density increases in the apical half
A - A clinical report by Appleton et al. demonstrated that progressively loaded single-tooth implants in the first premolar region of human beings exhibited greater bone density increase in the crestal half of the implant interface and less marginal bone loss compared with nonprogressively loaded implants in the same jaw region
Which of the following statements is false:
A) Bone density is directly related to strength
B) Dense cortical bone is 10x stronger than soft, fine trabecular bone
C) D2 bone is 50% stronger than D3 bone
D) Bone density is not related to stiffness
D - Dense cortical bone is 10 times stronger than the soft, fine trabecular bone. D2 bone is approximately 50% stronger than D3 bone.
stiffness of the bone is affected by the bone density. Young’s modulus for compact bone is 10 times larger than cancellous bone. The denser the bone, the stiffer the bone, and the less biomechanical mismatch to titanium during loading.
Which of the following statements is true:
A) Shorter implants are helpful for initial stability
B) Longer implants are better at resisting shear/torque forces when abutments are screwed into place
C) Longer implants do a lot to decrease the stress at the crestal bone interface during occlusal loading
D) Each 0.25mm decrease in diameter increases the implant surface area by 5 - 10%
B - An excessive implant length is not critical at the crestal bone interface, but rather for initial stability and the overall amount of bone-implant interface.
Each 0.25-mm increase in implant diameter may increase the overall surface area approximately 5% to 10% in a cylinder implant body.
The four most common complications for three-unit fixed prostheses are :
(1) caries,
(2) endodontic problems,
(3) unretained prosthesis, and
(4) porcelain fracture
Eleven different gingival fiber groups are observed around a natural tooth. Which six of these gingival fiber groups insert into the cementum of the natural tooth: 1- dentogingival (coronal, horizontal, and apical), 2- alveologingival, 3- intercapillary, 4- transgingival, 5- circular, 6- semicircular, 7- dentoperiosteal, 8- trans-septal, 9- periosteogingival, 10- intercircular, 11- intergingival.
dentogingival (coronal, horizontal, and apical), dentoperiosteal, trans-septal, circular, semicircular, transgingival fibers.
The relationship between stress and strain determines the modulus of elasticity (stiffness) of a material. The modulus conveys the amount of dimensional change in a material for a given stress level. The modulus of elasticity of a tooth is similar to ?
A) Trabecular Bone
B) Titanium
C) Cortical bone
D) A Dentist after a day of Maxicourse surgery
C) Cortical bone
The modulus of elasticity of titanium is five to ten times greater than that of cortical bone
Which of the following is true?
A) Bone is 60% mineralized at 3 months and takes 16 weeks to complete its mineralization.
B) Bone is 60% mineralized at 4 months and takes 52 weeks to complete its mineralization.
C) Bone is 100% mineralized at 4 months.
D) I really don’t have to know this mineralization stuff!
B) Bone is 60% mineralized at 4 months and takes 52 weeks to complete its mineralization.
Woven bone is:
A) highly organized and stronger than lamellar bone, which lines the socket.
B) Produced in small villages in the Himalayas and available through Himalayan Mountain Bone Inc.
C) Unorganized and weaker than lamellar bone, which is organized and more mineralized.
D) is highly mineralized bone.
C) Unorganized and weaker than lamellar bone, which is organized and more mineralized.
