• In eccentric jaw movements, it is important not to
have contact on the implant-retained restoration.
Whenever possible, disclusion is preferred over the
• Whenever possible, the implant should be placed in
the middle of the edentulous crest of the bone.
FIGURE 35-4 Greater crestal bone loss occurs when
angulated abutments are given.
Implant failures and their management
Failures in implants can be classified as follows:
Failures in implants related to surgery and initial
Failures in implant related to abutment connection
(iii) Screw loosening or cement failure
Failures in implants detected during follow-ups:
(i) Wear or breakage of the components
(ii) Soft tissue complications
(iv) Fracture of abutment screw
Failures in implant due to bacterial-induced factors:
(i) Poor oral hygiene of the patient
(ii) Retention of cement in the subgingival area
(iii) Macroscopic gaps between the implant components subgingivally
(iv) Marked inflammation, exudation and proliferation of the soft
Failures in implants related to initial healing
Mobile fixtures: If primary stability is not achieved during implant
placement, the fixture is primarily unstable and this prevents
• Overheating of bone during placement or failure to
achieve primary stability can result in loss of
• It can be managed by placing a standard length
implant with bigger diameter, if possible.
• Implant failure rate in smokers is almost twice as
• The patient is advised to quit smoking at least
during the first week of implant placement.
Mucosal fixtures: It can occur due to defective flap adaptation, suture
remnant granulomas or decubitus ulcer below the denture.
• It can be managed by excision of the perforation
site, flap mobilization, resuturing and proper
Failures in implants related to abutment
connection and initial loading
Abutment loosening: It can occur due to repeated loading of the
implant during chewing cycles or due to any parafunctional habits
• It can be managed by relieving any premature
occlusal contact and adequately tightening the
Occlusal factors: Factors which can lead to implant failures are:
• Patient having parafunctional habits
• History of breakage of the superstructure or
• An angular pattern of bone loss
• Too few implants to replace missing teeth
Screw loosening or cement failure: This can occur due to ill-fitting
prosthesis or excessive loading.
• Screw loosening can also occur, if the arch form is
• The causative factors should be eliminated to
• If there is repeated incidence of screw loosening, the
Failures in implant detected during follow-ups
Wear or breakage of the components: The common cause of wear or
breakage of components is ill-fitting prosthesis.
• Broken component is replaced and the ill-fitting
Soft tissue complications: The mucosa surrounding the abutment
should be checked for any inflammation.
• It may be caused due to poor implant positioning.
• The soft tissue is checked for increased probing
depth, soft tissue proliferation, bleeding, exudates
• The area is examined radiographically to determine
the loss of bone or loss of integration.
• Soft tissue complications may require surgical
• If there is adequate attached gingiva, simple
• A loosely tightened abutment screw may cause the
formation of the granulation tissue at the
• The granulation tissue is removed once the
• After the removal of granulation tissue, the
abutment screw is adequately tightened.
Exposed implant threads: It may occur due to horizontal bone loss.
• There may be soft tissue proliferation over the
• At the time of placement, the implant is placed deep
• Proper oral hygiene maintenance is important.
• There may be a need for periodontal therapy to
create attached gingiva by free mucosal or skin
Fracture of abutment screw: Ill-fitting prosthesis or overloading of
implant is common cause for fracture of the abutment screw,
although the incidence is low.
• The fractured abutment screw is first retrieved and
• New properly fitting prosthesis is constructed and
the broken screw is replaced with the new one.
Fracture of the fixture: Progressive horizontal bone loss is an
indication for stress concentration which can result in fracture of the
fixture over a period of time.
• The fractured fragment is removed using a small
• The area is inspected after removal of the fragment
and a new long abutment is placed.
• The junction of the abutment and the fixture is
checked for intimate fit using a radiograph.
Loss of implant: This may occur due to rapid horizontal and vertical
• The cause is evaluated and then treated first.
• After stabilization, another implant next to the site
Peri-implantitis is defined as ‘inflammation around the dental implant,
usually the dental abutment’. (GPT 8th Ed)
The inflammation occurs at the soft tissue implant interface. The
clinical signs of inflammation in the peri-implant soft tissues are:
• Plaque accumulation in peri-implant mucosa
• Periapical and vertical bitewing radiographs are helpful in
• Plastic periodontal probe is used to assess the gingival health and to
• No bleeding occurs on probing around implants because more rapid
breakdown occurs around implants in patient having poor oral
• Crestal bone loss with loss of perimucosal seal may occur.
• Mobility of implant can occur.
• Changes in the biochemical configuration of the crevicular fluid
• Good oral hygiene maintenance
• Proper use of oral hygiene aids
• Plastic or titanium instruments used to remove plaque and calculus
• Nonsurgical treatment is used by proper plaque control, oral
hygiene instructions, use of chlorhexidine mouthwash, treatment
with citric acid and sodium hypochloride to remove bacterial
• Surgical methods used for treating peri-implantitis are
mucogingival therapy, open debridement, apically positioned tissue
grafting, guided tissue regeneration and removal of implant.
• Implant is removed only in rare cases.
Immediate loading refers to a nonsubmerged implant which is placed
in single-stage surgery and is loaded with the provisional restoration
in the same appointment or shortly thereafter.
Immediate loading is a technique in which implants are restored, and
thus loaded at the time of the placement.
• Temporary restoration fitted on the same day as surgery and is in
• Patient is advised soft diet.
Immediate nonfunctional loading
• Temporary restoration fitted on the same day as surgery but is not
• Patient is advised soft diet.
FIGURE 35-5 Immediate functional loading.
Rationale for implant immediate loading
• Minimizes thermal injury and surgical trauma
• Acceleratory phenomenon of bone repair
• The interface is the weakest, at risk of overload at 3–6 weeks after
• Temperature: 38–41°C (M. Sharawy, C.E. Misch, N. Wellner, 2002)
and not above this range during osteotomy
• Slow intermittent pressure with irrigation and usage of sharp drills
• To reduce the risk of fibrous tissue formation
• To minimize woven bone formation and promote lamellar bone
• It preserves alveolar bone; biostimulation occurs, so ridge height
• Aesthetic results can be obtained.
• Case selection would be difficult.
• It may need soft tissue and hard tissue augmentation at a later date.
• In implant-retained overdenture for completely edentulous patient,
balanced occlusion or lingualized occlusion is given.
• In full fixed arch implant-supported bridges, there should be
simultaneous contact on the anterior and posterior teeth in centric
relation with anterior group function and multiple contacts in
• Guided bone regeneration is used for the treatment of localized
ridge defects and to regenerate bone in dehiscence and
• During osteotomy, care should be taken that the bone should not be
heated above 47ºC, as this will lead to bone cell death.
• Oil rig style bridge is made of standard cylindrical abutments
which are joined together with a composite resin bar used mostly in
the lower arch where aesthetics is not a primary concern.
• Misch occlusal analyser is used to evaluate the occlusal plane of the
patient before the restoration of the opposing arch.
• Minimum crown height space needed for the fixed implant
• The distance from the centre of the most anterior implant to a line
joining the distal aspect of the two most distal implants is called the
anteroposterior distance or (A-P spread).
• Greater the A-P spread, more favourable is the situation of the
• The tip of the osteotomes is usually concave and blunt so as to
minimize the chances of tearing the Schneiderian membrane
• In group function occlusion, there is contact of all the teeth on the
working side and there is no contact on the balancing side.
• Shim stock is the most accurate method of checking occlusion for a
• Anterior mandible is the ideal location for placement of implants.
• The intraoral sites for harvesting bone for autogenous graft are
maxillary tuberosity, mandibular symphysis, mandibular ramus or
• Recently introduced zirconia abutments provide excellent
• The implant should be placed at least 2 mm longer than the tooth
socket for good primary stability.
1. Write problems associated in cases of having single complete
dentures opposing natural remaining teeth.
2. Discuss dentogenic concept with reference to aesthetics in complete
3. ‘Establishing and verification of correct vertical jaw relations for
complete dentures always poses a challenge to prosthodontist’.
4. Write causes and methods of correcting occlusal discrepancies in
5. Discuss the advantages and shortcomings of balanced occlusion in
6. Describe the techniques of producing balanced occlusion.
7. Describe Bennett movement. How are these incorporated in various
8. Describe the biological aspects to be considered during complete
9. Discuss the importance of centric relation in complete dentures.
10. Describe the methods of obtaining centric relation for the
11. Discuss the usefulness of facebow. Give a brief historical account
of the origin and development of facebow.
12. Discuss the effects of complete dentures on hard and soft tissues of
the oral cavity with special reference to measures to minimize it.
13. Discuss the rationale for selecting artificial teeth for edentulous
14. Give an account of the evolution of artificial posterior tooth form.
15. Give an account of factors affecting occlusion in complete
16. Discuss the evolution of articulators.
17. Discuss the significance of ‘hinge axis’ theory of mandible. Give
your comments on its clinical importance in prosthodontics.
18. Discuss the objectives and procedure of selective grinding in
19. Discuss aesthetics and phonetics in complete denture prosthesis.
20. Discuss the factors for retention of complete dentures with a
special reference to posterior palatal seal.
21. Discuss the role of mandibular rest position as it relates to
complete denture prosthodontics.
22. Discuss how facial and functional harmonies are achieved during
arrangement of artificial teeth for complete dentures.
23. Discuss the muscle tone and its relationship to vertical dimension.
24. Discuss the importance of anterior guidance during aesthetic
25. Define patient education. Discuss the role of patient education and
patient motivation in the success of a complete denture therapy.
26. Describe the nutritional factor in complete denture patient.
27. Write briefly the procedure of making an impression of flabby
28. Discuss the treatment of abused tissues in complete denture
29. Define vertical jaw relations. What are the different methods by
which vertical jaw relations can be recorded?
30. Write a note on neutral zone.
31. Describe the peripheral structures affecting mandibular dentures.
32. Discuss the degenerative changes in the oral cavity on account of
ageing and its effects in the fabrication of complete dentures.
33. Discuss the preprosthetic surgery in the treatment of completely
34. Write a short note on masticatory efficiency of complete dentures.
35. Write a short note on denture cleansers.
36. Discuss posterior palatal seal as an indispensable clinical step in
maxillary complete dentures. Describe the methods of recording
37. Discuss the theories of impression making in complete dentures.
38. Discuss the critical role played by border moulding lingual flange
of the special tray in the stability of mandibular complete dentures.
39. ‘Troubleshooting in complete dentures prosthesis’. Discuss the
statement and your management.
40. ‘Immediate denture service designed to preserve oral structures’.
Discuss the merits and demerits of this statement.
41. Write importance of incisive papilla in the arrangement of anterior
42. Discuss the gothic arch tracings as related to the various
movements of lower jaws with special reference to the development of
43. What are jaw relations? How will you record the following
relations with maximum accuracy: (i) orientation of the plane of
occlusion, (ii) vertical dimension of occlusion (VDO) and (iii) centric
44. Define centric relation. Describe the technique of registering
centric relation in clinic for an edentulous case.
45. Write a short note on age changes in edentulous patients.
46. Write a short note on special tray for edentulous mouth.
47. Describe briefly about the sequelae of wearing complete dentures.
48. Describe briefly about the anatomy of maxillary denture-bearing
49. Write a short note on residual ridge resorption.
50. Write a short note on alveololingual sulcus.
51. Define retention, stability and support. Describe the biological,
mechanical and physical factors which promote these qualities in
52. Define impression. Classify the different types of impression in the
53. Differentiate between the mucostatic and mucocompressive
54. Discuss the statement ‘artificial denture can be a boon to the
patient, but artificially looking denture a curse’.
55. Explain in detail about the anatomy and physiology pertaining to
the maintenance of physiological rest position of the mandible with a
detailed note on muscle tone, muscle spindle and myotatic reflex.
56. Explain the significance of centric and eccentric jaw relations. Give
a critical evaluation of the methods to record centric jaw relations.
57. Explain the methods of making interocclusal records and
establishing the centric relations of partially edentulous conditions.
58. Discuss the rationale and technique of relining complete dentures.
59. Discuss the movements and the various reference positions of the
60. Describe the rationale and technique of ridge augmentation for
61. Write a short note on the evaluation of methods to obtain vertical
62. Write a short note on bar designs in overdentures.
63. Write a short note on Bennett movement.
64. Write briefly about the theories of occlusion.
65. Critically evaluate the various posterior tooth forms with respect
to balanced occlusion and masticatory efficiency.
66. Write a short note on border moulding of lingual crescent.
67. Write a short note on reduction of residual ridge.
68. Write a short note on semi-adjustable articulators in practice.
69. Discuss the statement ‘temporomandibular joint controls
biomechanical phase of prosthetic rehabilitation’.
70. Discuss the recent trends in prosthodontics research in complete
71. Describe the importance of characterization of the denture base
and anterior teeth with reference to the aesthetics in complete
72. Discuss the concept of ‘overdenture philosophy’ in preservation of
73. How do you select posteriors for edentulous patients with
74. Write short note on resilient permanent soft liners?
75. Define denture aesthetic. Discuss its importance in complete
76. Describe the types of denture teeth on the basis of materials and
77. Write about the selection of anterior teeth in complete denture
Comments
Post a Comment
اكتب تعليق حول الموضوع