Dental Implant Assessment and Treatment.
22 Feb 2011
Patient assessment is absolutely essential for planning implant treatment. The assessment is undertaken in two phases:
- Preparation phase
During this phase, the clinician discusses with the patient their primary dental problems, medical history and expectations. Treatment is initiated so that the patient can be assessed with a view to progressing into the next phase which is:
- Definitive planning phase
Once all the primary problems have been dealt with, definitive treatment planning can start. A full assessment and evaluation for planning the replacement of missing teeth with an implant-retained prosthesis is undertaken.
The benefits of the assessment phase are:
- It gives the dental team the opportunity to obtain a full evaluation of the patient including their concerns, expectations and medical/dental history.
- It also gives the dental team the opportunity to build rapport with the patient and hopefully gain their confidence and trust.
- The patient’s attitude to treatment can be ascertained.
- Patients who have unrealistic expectations of the treatment outcomes can be identified and informed.
- The history that the patient gives will help identify the cause of tooth loss and will give some indication about the level of patient compliance and motivation for treatment.
- It allows the dental team to identify whether the patient is currently wearing a denture and whether they are coping with it.
- The patient’s suitability for surgery and their ability to cope with long procedures is determined during this phase.
The next stage is an extra-oral and intra-oral examination.
The extra-oral examination involves assessing the patient’s smile line, facial height and
facial profile, as well as the asymmetry and the patient’s mouth opening.
The intra-oral examination involves assessment of the following:
- Soft tissue assessment: an assessment of the soft tissues, including the sulcus depth and the contour, is undertaken and the relationship with the adjacent teeth is evaluated.
- Periodontium: the health of the gum tissues is determined including the quality of the gum tissues, which is called the biotype. The amount of keratinised tissue present is also recorded in the site of the implant placement.
- Teeth: how many teeth are present, including their condition, is assessed along with the recording of missing teeth. The intended tooth position is determined and evaluated against the underlying soft tissue. Additionally, the presence of any over-eruption of drifting is recorded.
- Occlusion: the intra and inter-occlusal relationship of the teeth is assessed and an analysis undertaken of any interferences.
- Other investigations: including OPG and periapical radiographs which give an overview of the dental structures and also an indication of the anatomical structures in relation to the site of the missing teeth, condition of the existing teeth and the alveolar bone height.
Once the clinician has completed the basic assessment, he/she will be able to judge the patient’s suitability for implant treatment. Extra factors included in making this decision are:
- Case complexity.
- Supplementary diagnostic information relating to the bone height and width.
- Type of prosthetic replacement to use.
Because patient demands are increasing and cases are becoming more complex, meticulous treatment planning is absolutely essential. To supplement the basic assessment, the following diagnostic aids are needed to finalise the treatment plan:
- Study models: these give an accurate assessment of the site of implant placement viewed outside the mouth on a model. The models should ideally be mounted on an articulator so that the relationship of the upper and lower jaws is determined and an assessment of the teeth can be undertaken three dimensionally. These study models can also be shown to the patient at the end of treatment as a pre-operative model, in comparison to the final result.
- Diagnostic wax-up: this is a mock up of the ideal end result. It shows the intended position of the teeth that are to be replaced. Other benefits are that it helps identify the shape and size of the teeth to be replaced and their relationship to the existing teeth along with the impact of any soft tissue loss and any possible need for bone augmentation. It is a great tool to show the patient as they get to see what their teeth will look like at the end and this may help them make a final decision. The diagnostic wax up is also used to obtain radiographic and surgical guides thus ensuring the intended replacement tooth position is replicated accurately.
- Radiographic template: this is normally made using the diagnostic wax up (or the denture if the patient has been wearing a denture where the tooth position is acceptable). The radiographic guide will contain a radiopaque material in the teeth to be replaced, so that when the radiograph is taken with the stent in position, the intended tooth position is replicated onto the radiographic image thus relaying this position to the underlying bone and soft tissue. The radiographic templates also help incorporate the proposed treatment plan into the radiographic examination so that an indication of the need for soft and hard tissue augmentation to meet the restorative needs can be made.
- Bone mapping: this is normally done if additional radiographic facilities are unavailable. It is particularly useful for single tooth replacement. Bone mapping can also be a cost-effective alternative to gain information on the buccolingual dimension of the bone available for implant placement. It involves placing local anaesthesia into the potential implant site and using a sharp probe with markers on it to assess the depth of the soft tissue at recorded intervals. This information is then transferred to a cross sectioned study model at the intended implant site.
- Specialist radiographs: in addition to an OPG and basic periapical radiographs, it is sometimes necessary to refer the patient for a lateral tomogram (these films give an indication of the buccolingual dimension) or computerised tomogram (gives an outline of both the soft and hard tissues using interactive three-dimensional imaging).
The next stage is decision making.
Once all the data has been collected during the assessment phase, including all the additional aids, a risk-assessed treatment plan that is designed to satisfy all the patient’s presenting complaints is created. The patient is shown the diagnostic wax up and all the tooth replacement options, including implants, are discussed. Risks and benefits are discussed and bone augmentation is discussed and explained if necessary. Sedation can also be discussed providing the patient is particularly anxious or phobic and the clinician can offer it. The decision making process will alert the patient to the following:
- The recommended implant retained restoration for them.
- The need for bone augmentation if applicable.
- The need for soft tissue augmentation if applicable.
- Sedation and what it involves if the patient requests it.
- The healing period and the time frame between the implant placement and the fitting of the restoration.
- Risks associated with the treatment including implant failure.
- Short and long term complications associated with the treatment.
- The need for long term maintenance and support in order to ensure maximum longevity.
The next stage is starting treatment.
The phases of implant treatment are:
- Surgical placement of the implant(s): the implant placement will take place and an aseptic sterile technique is followed. The implant is placed into the bone as directed by the surgical guide, which gives the clinician an idea of the final tooth position and helps ensure that the implant is placed within the desired prosthetic location. The site is prepared by using a series of drills which are customised to the specific implant system being used, e.g. Astra Tech or Straumann®. Whilst the clinician is drilling, the nurse will be cooling the site with sterile water. Overheating of the bone can lead to bone cell death (necrosis). Implant placement can take place in either one or two stages. The one stage procedure involves placing a healing abutment on the head of the implant straight after placement, allowing the implant to be exposed above the gum and then reviewing at a later date to commence with the restoration. The two stage procedure involves keeping the implant buried under the gum and then reviewing at a later date to expose the implant and then connect the healing abutment. Exposure of an implant requires the same aseptic technique of an implant placement. Once the healing abutment has been connected, the bone is left to heal for anywhere between 4 weeks to 6 months depending on the case. Some patients can have their restoration immediately placed however this depends on many factors.
Prosthetic reconstruction: This can begin after the healing period and can be undertaken at: 4-6 months after osseointegration, 4-8 weeks after osseointegration or immediately after the implant placement. Impressions are taken using special impression copings and sent to the laboratory-sterile, labelled and marked with the patient’s details. All instructions will also be included on the lab ticket. The lab technician will also usually request a jaw registration or bite block and shade from the patient. If the prosthesis is a denture, then the usual registration, try and fit appointments are required. Crown/bridgework will generally consist of a final preparation and fit appointment.
Long term maintenance is essential in order to ensure optimum health and longevity of the implant and restoration.