Dr Suneel Chagger
CONSENT FOR IMPLANT TREATMENT
Consent is an active process of agreement and understanding by an individual for a treatment or procedure to be performed on them. If they are under 16 and/or are unable to satisfactorily give their own consent or not be in a capacity to give consent, a parent or guardian may do it for them. The decision whether the individual is incapable or incompetent of giving the consent lies with the judgement of the professional.
In all instances the professional must do his best to help the patient understand and involve him in the decision and consent process. This can be done by assessing if the person:
-Needs new skills or knowledge e.g. more explanation, more time, or need to be subjected to new experiences.
-Has someone e.g. carer, guardian or parent who can help with the communication process.
If after these steps, the person is still deemed incapable to make a consent a parent or guardian is able to do it for them. Occasionally if the treatment is necessary and in the patients best interest, the health professional can make the decision as long as it would be accepted by a similar peer group. This is usually common in life threatening or hospital environments. When considering the patients best interest, we must try to respect the patients beliefs and ethics eg cultural or religious such as use of animal materials that they would not want used as they are vegetarians or due to religious factors. (1,2)
In todays legal climate it is essential for practitioners to communicate with the patient so they understand and give their valid consent for treatment. In not doing so the practitioner is breaking his moral, ethical and possibly his legal duties. Individuals deemed not in capacity to consent, must still be provided with all the information in simple language that is required to:
1. Understand what the consent is for and what procedures are to be performed and why.
2. Understand the benefits, risks, costs and any alternatives.
3. Understand the risks involved if they were not to consent.
4. Remember the information, if needed have someone present and provide them with relevant literature, or media sources such as web sites /CD Roms etc. They must then be given enough time to absorb this information and understand it. How much time would have to be agreed by both parties.
5. Make a decision without any pressure or persuasion.
There are two types of consent which a patient could express (3)
1. IMPLIED. In this, consent for treatment is given by assessing a patients behaviour. For example if the patient attends the surgery, sits down, mouth open, a dentist may examine him and carry out other types of checks and minor procedures.
2. EXPRESSED. In this, the patient has expressed either verbally or by writing to have a procedure done. This is very important in dentistry where procedures are often physical, irreversible, or incurs some sort of risk or cost e.g. implants, bleaching or extractions. The majority of procedures carried out in dentistry e.g. fillings, scaling etc is done with verbal consent, but they too should have written consent as litigation increases, treatment options are increasing and patients are becoming more prudent and want more involvement in the decisions. For specific treatments such as implants, a verbal consent and a customised written consent should be taken. This is signed and forms a part of the records. This may need to be amended if the course of treatment changes, and in order to re-validate it the patient must again fully understand and consent to the change of treatment. In some situations procedures may change during the treatment for example bone grafting may be required for a minor defect during implant. These situations should be anticipated and the patients consent taken at the onset as it is now not feasible to stop the surgery, raise the chair and go through the whole consent procedure again especially if the patient is temporarily not in capacity to give consent e.g. Numb, sedated, disorientated etc.
Any type of consent can be withdrawn at any time by the patient.
The Implant consent form should be non-clinical jargon as possible so anyone can understand it. Difficulties can occur where terms like Osseo integration, autogenous bone graft or sinus lift are common terms. Possible risks should be mentioned along with how rarely they occur without going too much in depth. Unnecessary information is a high cause of patient stress and the chances are they may go elsewhere or not have the treatment altogether. A study by Casap N et al (4) concluded that patient who were given an overdisclosed documentation on having their wisdom tooth extracted had higher stress levels, measured through blood pressure, pulse and electrodermal activity. Asking patients their opinions as to whether they appreciated the information would help. It must also be set out in a clear concise manor with large clear fonts.
The consent used in our practice:
1. The patient understands everything involved in implants, given enough time to absorb any information and allowed to ask questions before making a decision to consent without pressure.
2. The treatment plan, its risks, benefits, costs and alternatives. These should outline each stage of the implant placement and the approximate times of them. Causes and risks of failure and the terms with which we will cover this, if this was to happen e.g no smoking, trauma not covered, regular checks.
3. Possible outcomes during and post-surgery, e.g. pain, swelling, the need for bone grafting.
4. Patient is able to specifically consent to having photos and the use of the records for other purposes e.g. cases, advertising, education.
This list should form the core of the consent. In the future more may be added when consents start becoming contract like, and healthcare professionals start handing them out as so for every procedure. It is for this reason that we must try to accept and imply the true value of a consent as a procedure through mutual understanding, communication and respect for the benefit of both the patient and the dentist. (5).
References
(1) Department of Health. Good practice in consent implementation guide: consent to examination or treatment.
(2) Department of Health. Reference Guide to Consent for Examination or Treatment.
(3)Yuill R. Consent in dentistry. Dental Profile. 2001;6-8.4
(4)Casap N. Alterman M. Sharon G. Samuni Y. The effect of informed consent on stress levels associated with extraction of impacted mandibular third molars. Journal of Oral & Maxillofacial Surgery. 66(5):878-81, 2008 May.
(5) Terry PB. Informed consent in clinical medicine. Chest. 131(2):563-8,2007Feb.
Wednesday, 26 November 2008
Dr. Suneel Chagger
Bone grafts from Intraoral Donor Sites
Introduction and Principles
Bone is a continuously modifying dynamically depositing, resorbing and remodelling. This is the basis through which bone grafting works.
The two types of bone grafts frequently used are:
1. Autografts -recipients own
2. Allografts. -from another member of the same species.
Ideal bone grafts are osteoinductive/conductive, biomechanically stable, disease free and contain minimal antigenic factors as usually is autograft bone. Allografts as well as not having these properties, have delayed vascular penetration, and union can be delayed or incomplete. They are osteoconductive but slightly osteoinductive. The structure of grafts vary:
a) Cortical- +density=-angiogenesis=-osteoblasts+osteocytes=graft becomes weaker initially due to more ostoecyte activity.
b) Cancellous -density=+angionesis=+osteoblasts-osteocytes=graft becomes stronger due to more osteoblast activity.
Therefore graft selection is important as it influences the structure and integrity of the substituting bone, aswell as the interface contact that effects the speed of vascular ingrowth.
Healing occurs in three distinct stages
1. Early Inflammatory- haematoma =+inflammatory/fibroblast cells infiltrate =+ neurovasculature formation =+ mesenchymal cells.
2. Repair- fibroblasts =+ callus. This is quite soft for up to seven weeks and so the union must be properly immobilized and protected to prevent fibrous union.
3. Remodelling- over years. Mechanical forces influence osteoblast/clast activity laying and resorbing bone to balance out stresses and through creeping substitution necrotic bone is replaced with new.
Intraoral donor sites
The most common sites for intraoral bone grafts are
1) mandibular symphysis- Membranous grafts revascularise more rapidly than endochondral types which have a thicker cortical component(1)
2) mandibular ramus.
Misch(2) et al reported in a comparison of symphysis and ramus grafts, that out of 31 patients symphysis patients were concerned regarding the compromise to the chin shape and contour, had greater postoperative sensory disturbance and greater chance of infection(2/31). The ramus had poorer access, grafts were thinner and cortical. To note. there were only 50 grafts performed and there were 22% more patients having sympyhsis graft, and conditions such as Patient compliance, immune control, and surgical sepsis may have varied all the results should not be conclusive.
3) mandibular/lingual tori - these occur quite infrequently but can be used and may even benefit the patient if they are large and effect speech, dentures etc.
4) Zygomatic bone -. Kainulainen(3) et al concluded that this was a safe donor site for
smaller defects based on a study on 20 cadavers. A total of 22 perforations into the sinuses were observed from ct scans in nearly half the specimens. Patient morbidity/discomfort as well as the operator skill requirement was also not considered when reaching the conclusion.
5) palate.
Graft structural composition depends on the manner by which it is extrapolated or prepared e.g. bone chunks, rings, chips, crushed, powdered (bone trap), mixed. Each has its own advantages and disadvantages and user preference.
Selection criteria
The selection criteria for donor source depends on the size/shape of the defect and on the availability of bone. These can be determined by the use of x-rays (OPT,PA,CT) and ridge mapping. Bearing in mind
1.the donor block should be away from teeth apices(5mm) and the inferior borders,
2. The third molars could prevent adequate harvest
3. The ID canal is away from the site.
4. Magnifications from x-rays are calibrated.
A Sethi et al(4) used the symphysis for 1-6 implant for small defects (2-4 mm), and the ramus for 1-2 implants with larger defect (6mm width and/or 4mm height). This is generally accepted by many authors who have also cited the high success rate of local block grafting. Dr D Schwartz-Arad(5), based on a study of ten patient files concluded” Intraoral bone block grafting is a predictable operation with a high success rate for longspan augmentation, up to complete jaw augmentation/ extensive bone reconstruction of the maxillary alveolar ridge“ . Although this was only studied till up to the implants were placed, only four of the ten files reviewed were totally uneventful.
Surgical principles
The fundamentals of surgery is the planning. The post tooth position must be determined so that we have a goal at aim for. This can be done by means of models with teeth on them and templates/stents. Surgery should always start at the recipient site in order to confirm the size and shape of the defect. Post operative management includes the use of antibiotic, anti inflammatory, cold packs and steroids to kerb pain and swelling
Soft tissue management
1. Bevelled incisions full thickness and divergent releasing incisions help to relocate the flap and maintain blood supply. The maxilla -remote palatal, The mandible - crestal. Papillaes maintained and released past adjacent teeth. .
2. Complete and tension free interrupted sutures- Periostium on the flap can be scored and periosteal released, or a soft tissue graft attached to allow stretching.
Access to graft sites:
a) Symphysis i)small grafts require sulcular incision between the canines.
ii)Larger require full thickness flap from ginivalmargin distal of the formina, (which is exposed and protected), Both are reflected to the lingual border.
b) Ramus Avoiding buccal and lingual nerves raise flap along the ridge distal and around the 2nd molar to expose the lateral ramus and the external oblique ridge.
Hard Tissue management
1. Evaluate the size of the defect and from where the graft is going to come.
2. The recipient bed is perforated with a small round bur and contoured to improve and accept the graft contact.
3. Symphysis grafts- fine fissure bur, and chisels. The superior osteootomy must be angulated downwards atleast 5mm below the apices and the inferior margin above and parallel to the inferior border.
Ramus is also initially marked for the 3d donation with fissure and round burs. The lower being a groove made by a large round bur above the ID canal.
4. Graft is removed, placed quickly, and stabilized with titanium screws. A membrane or particulate bone can be used if there are minor deficiencies.
Clinical applications
Grafting procedures will become more and more frequent as training/research and patients desire to have more aesthetic and stable implants increases. Areas where bone deficiencies or poor quality bone prevent the ideal placement of an implant which may lead to an unaesthetic or unstable implant/crown can now be rectified through knowing when to use specific grafting techniques with the science of graft healing and providing a more satisfactory results.
References
(1) Misch CM, Misch CE. The repair of localized severe ridge defects for implant placement using mandibular bone grafts. Implant Dent. 1995;4:261-67.
(2) Misch CM. Comparison of intraoral donor sites for onlay grafting prior to implant placement. Int J Oral Maxillofac Implants. 1997;12:767-76.
(3) V T Kainulainen, G K B Sàndor, C M L Clokie, A M Keller, K S Oikarinen The zygomatic bone as a potential donor site for alveolar reconstruction--a quantitative anatomic cadaver study.Int J Oral Maxillofac Surg. 2004 Dec ;33 (8):786-91
(4) Sethi A, Kaus T. Ridge augmentation using mandibular block bone grafts: preliminary results of an ongoing prospective study. Int J Oral Maxillofac Implants. 2001;16:378-88.
(5) Dr. Devorah Schwartz-Arad Intraoral Autogenous Block Onlay Bone Grafting for Extensive Reconstruction of Atrophic Maxillary Alveolar RidgesJ Periodontol 2005;76:636-641
Bone grafts from Intraoral Donor Sites
Introduction and Principles
Bone is a continuously modifying dynamically depositing, resorbing and remodelling. This is the basis through which bone grafting works.
The two types of bone grafts frequently used are:
1. Autografts -recipients own
2. Allografts. -from another member of the same species.
Ideal bone grafts are osteoinductive/conductive, biomechanically stable, disease free and contain minimal antigenic factors as usually is autograft bone. Allografts as well as not having these properties, have delayed vascular penetration, and union can be delayed or incomplete. They are osteoconductive but slightly osteoinductive. The structure of grafts vary:
a) Cortical- +density=-angiogenesis=-osteoblasts+osteocytes=graft becomes weaker initially due to more ostoecyte activity.
b) Cancellous -density=+angionesis=+osteoblasts-osteocytes=graft becomes stronger due to more osteoblast activity.
Therefore graft selection is important as it influences the structure and integrity of the substituting bone, aswell as the interface contact that effects the speed of vascular ingrowth.
Healing occurs in three distinct stages
1. Early Inflammatory- haematoma =+inflammatory/fibroblast cells infiltrate =+ neurovasculature formation =+ mesenchymal cells.
2. Repair- fibroblasts =+ callus. This is quite soft for up to seven weeks and so the union must be properly immobilized and protected to prevent fibrous union.
3. Remodelling- over years. Mechanical forces influence osteoblast/clast activity laying and resorbing bone to balance out stresses and through creeping substitution necrotic bone is replaced with new.
Intraoral donor sites
The most common sites for intraoral bone grafts are
1) mandibular symphysis- Membranous grafts revascularise more rapidly than endochondral types which have a thicker cortical component(1)
2) mandibular ramus.
Misch(2) et al reported in a comparison of symphysis and ramus grafts, that out of 31 patients symphysis patients were concerned regarding the compromise to the chin shape and contour, had greater postoperative sensory disturbance and greater chance of infection(2/31). The ramus had poorer access, grafts were thinner and cortical. To note. there were only 50 grafts performed and there were 22% more patients having sympyhsis graft, and conditions such as Patient compliance, immune control, and surgical sepsis may have varied all the results should not be conclusive.
3) mandibular/lingual tori - these occur quite infrequently but can be used and may even benefit the patient if they are large and effect speech, dentures etc.
4) Zygomatic bone -. Kainulainen(3) et al concluded that this was a safe donor site for
smaller defects based on a study on 20 cadavers. A total of 22 perforations into the sinuses were observed from ct scans in nearly half the specimens. Patient morbidity/discomfort as well as the operator skill requirement was also not considered when reaching the conclusion.
5) palate.
Graft structural composition depends on the manner by which it is extrapolated or prepared e.g. bone chunks, rings, chips, crushed, powdered (bone trap), mixed. Each has its own advantages and disadvantages and user preference.
Selection criteria
The selection criteria for donor source depends on the size/shape of the defect and on the availability of bone. These can be determined by the use of x-rays (OPT,PA,CT) and ridge mapping. Bearing in mind
1.the donor block should be away from teeth apices(5mm) and the inferior borders,
2. The third molars could prevent adequate harvest
3. The ID canal is away from the site.
4. Magnifications from x-rays are calibrated.
A Sethi et al(4) used the symphysis for 1-6 implant for small defects (2-4 mm), and the ramus for 1-2 implants with larger defect (6mm width and/or 4mm height). This is generally accepted by many authors who have also cited the high success rate of local block grafting. Dr D Schwartz-Arad(5), based on a study of ten patient files concluded” Intraoral bone block grafting is a predictable operation with a high success rate for longspan augmentation, up to complete jaw augmentation/ extensive bone reconstruction of the maxillary alveolar ridge“ . Although this was only studied till up to the implants were placed, only four of the ten files reviewed were totally uneventful.
Surgical principles
The fundamentals of surgery is the planning. The post tooth position must be determined so that we have a goal at aim for. This can be done by means of models with teeth on them and templates/stents. Surgery should always start at the recipient site in order to confirm the size and shape of the defect. Post operative management includes the use of antibiotic, anti inflammatory, cold packs and steroids to kerb pain and swelling
Soft tissue management
1. Bevelled incisions full thickness and divergent releasing incisions help to relocate the flap and maintain blood supply. The maxilla -remote palatal, The mandible - crestal. Papillaes maintained and released past adjacent teeth. .
2. Complete and tension free interrupted sutures- Periostium on the flap can be scored and periosteal released, or a soft tissue graft attached to allow stretching.
Access to graft sites:
a) Symphysis i)small grafts require sulcular incision between the canines.
ii)Larger require full thickness flap from ginivalmargin distal of the formina, (which is exposed and protected), Both are reflected to the lingual border.
b) Ramus Avoiding buccal and lingual nerves raise flap along the ridge distal and around the 2nd molar to expose the lateral ramus and the external oblique ridge.
Hard Tissue management
1. Evaluate the size of the defect and from where the graft is going to come.
2. The recipient bed is perforated with a small round bur and contoured to improve and accept the graft contact.
3. Symphysis grafts- fine fissure bur, and chisels. The superior osteootomy must be angulated downwards atleast 5mm below the apices and the inferior margin above and parallel to the inferior border.
Ramus is also initially marked for the 3d donation with fissure and round burs. The lower being a groove made by a large round bur above the ID canal.
4. Graft is removed, placed quickly, and stabilized with titanium screws. A membrane or particulate bone can be used if there are minor deficiencies.
Clinical applications
Grafting procedures will become more and more frequent as training/research and patients desire to have more aesthetic and stable implants increases. Areas where bone deficiencies or poor quality bone prevent the ideal placement of an implant which may lead to an unaesthetic or unstable implant/crown can now be rectified through knowing when to use specific grafting techniques with the science of graft healing and providing a more satisfactory results.
References
(1) Misch CM, Misch CE. The repair of localized severe ridge defects for implant placement using mandibular bone grafts. Implant Dent. 1995;4:261-67.
(2) Misch CM. Comparison of intraoral donor sites for onlay grafting prior to implant placement. Int J Oral Maxillofac Implants. 1997;12:767-76.
(3) V T Kainulainen, G K B Sàndor, C M L Clokie, A M Keller, K S Oikarinen The zygomatic bone as a potential donor site for alveolar reconstruction--a quantitative anatomic cadaver study.Int J Oral Maxillofac Surg. 2004 Dec ;33 (8):786-91
(4) Sethi A, Kaus T. Ridge augmentation using mandibular block bone grafts: preliminary results of an ongoing prospective study. Int J Oral Maxillofac Implants. 2001;16:378-88.
(5) Dr. Devorah Schwartz-Arad Intraoral Autogenous Block Onlay Bone Grafting for Extensive Reconstruction of Atrophic Maxillary Alveolar RidgesJ Periodontol 2005;76:636-641
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