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| INVITED REVIEW |
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| Year : 2015 | Volume
: 7
| Issue : 3 | Page : 13-18 |
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Basics of clinical diagnosis in implant dentistry
Manu Rathee, Mohaneesh Bhoria
Department of Prosthodontics, Post Graduate Institute of Dental Sciences, Pandit Bhagwat Dayal Sharma University of Health Sciences, Rohtak, Haryana, India
| Date of Web Publication | 31-Dec-2015 |
Correspondence Address:
Manu Rathee
Department of Prosthodontics, Post Graduate Institute of Dental Sciences, Pandit Bhagwat Dayal Sharma University of Health Sciences, Rohtak - 124 001, Haryana
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/2231-0754.172929
 Abstract | | |
Implant-based prosthetic rehabilitation requires an understanding of associated anatomical structures. The ultimate predictability of an implant site is determined by the existing anatomy as related to dentition and the associated hard and soft tissues. Meticulous clinical assessment helps in determining the suitability of the potential site for implant placement. The purpose of this article is to present the clinical assessment for dental implants' placement to modulate peri-implant tissue characteristics in individual clinical need. Keywords: Dental implant, diagnosis, gingival biotype, residual ridge
How to cite this article:
Rathee M, Bhoria M. Basics of clinical diagnosis in implant dentistry. J Int Clin Dent Res Organ 2015;7, Suppl S1:13-8 |
| Introduction | |  |
Implant-based rehabilitation approach for an edentulous or partially dentulous condition requires a series of decisions that are taken to determine whether the patient is a reasonable candidate for implant therapy. Every effort should be made to preserve the natural tooth through restorations. Clinical evaluation to assess the suitability of the candidate for dental implant is a vital phase of treatment planning before implant surgery. The prognosis of implant surgery depends primarily on the desired prosthetic result.[1] Hence, such rehabilitation procedure requires a clear vision of the end result before the procedure begun. Clinical evaluation for dental implant placement requires overall condition assessment that resembles traditional dentistry. When a clinician evaluates the prosthetic need of patients, an orderly sequence is required regardless of the current status of the dentition. In other words, whether the patients are partial dentate or edentate, consistent approaches to evaluate before the management are beneficial.[2],[3]
Clinical diagnosis
Various factors have been discussed in the literatures that facilitate clinical assessment for dental implant selection and placement with consequent hard and soft tissue enhancement around the implant prosthesis. These factors are broadly categorized as the anterior (single/multiple) and posterior quadrants (single/multiple) [Figure 1]. The dentist must evaluate the elements during clinical examination as shown in [Figure 2]. | Figure 1: potential prognostic clinical assessment for dental implant placement
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General assessment of the patient's profile
The initial decisions involve meticulous case history involving medical and psychological examination for implant therapy. A medical evaluation is made from a questionnaire, a patient interview, and any medical consultations necessitated by the history. Medical conditions that make surgery complicated or adversely affect healing must be taken into consideration. If any significant medical contraindication exists and cannot be resolved promptly, implants are not indicated and alternative approaches must be sought.[3],[4] If the patient is medically and psychologically well-adjusted and understands the aesthetics or functional benefits of an implant approach, the consequences of the edentulous or partially dentulous condition should be considered next.[2],[3]
Specific assessment of patient profile
Meticulous assessment of the future dental implant site is a must for optimizing healthy aesthetic gingival appearance and establishing a functionally successful implant-supported restoration.
Aesthetic assessment (lip lines, tooth position, and other features)
Implant placement requiring replacement of an anterior tooth
In almost all the cases, the primary concern is an aesthetic tooth replacement; it is important to establish clinical concepts with well-defined parameters for successful aesthetics outcome with long-term stability of the peri-implant tissues. The aesthetic evaluation involves lip activity and lip length. In an average smile, 75-100% of the maxillary incisors and the interproximal gingiva are displayed. In a high smile line, additional gingival tissues are exposed. Less than 75% of the incisors are exposed in a low smile line. Other aids, such as previous photographs, may help in determining the natural position of the patient's lip when smiling. Considerable challenges occur in a high smile line as the implant prosthesis and gingival tissues are completely displayed. In these types of clinical situations, maximal efforts toward maintaining peri-implant tissue support throughout the planning, provisional, surgical, and prosthesis phases will be required. The low smile line is a less critical scenario where the implant prosthesis interfaces are less visible behind the upper lip. The tooth position needs to be evaluated clinically in three planes, that is, apicocoronal, faciolingual, and mesiodistal. The clinical tooth position assessment will considerably influence the presenting gingival architecture, papilla height, and contact area location.[4],[5]
Existing three-dimensional clinical evaluation
The three-dimensional clinical evaluation is dependent on many elements listed as follows:
- Available space
- Soft tissue ridge support
- Periodontal status
- Occlusal considerations
Assessment of the available space
In the posterior region, clinical assessment should ensure that the implant prosthesis unit restores functions as close to the natural dentition as possible to allow appropriate reestablishment of the occlusion and embrasure forms.
Clinical evaluation of the mesiodistal space involves adequate prosthetic space assessment so as to reestablish adequate tooth contours. If prosthetic space is inadequate, enameloplasty of the adjacent teeth or orthodontic repositioning must be given consideration. The mesiodistal space required depends on the type and number of teeth being replaced. Clinically-based decisions need to be made with regard to the implant size. The following guidelines may be used when selecting implant size and evaluating the mesiodistal space for implant placement: The implant should be at least 3 mm away from the adjacent teeth, the implant should be at least 3 mm away from an adjacent implant, and the diameter of the implant should be selected based on the tooth to be replaced. Based on the above guidelines, for two 4-mm diameter dental implants, a space of 17 mm is required. This amount of space would suffice to replace two premolars. If two premolars and a molar are required, an additional space is necessary. This situation can be resolved by the placement of two dental implants and fabrication of a fixed partial denture (FPD) or placement of three dental implants. If three implants are planned, a total space of 24 mm is required [Figure 3]. Clinical evaluation of the buccolingual space, at least 6 mm of bone buccolingually, is required for the placement of a 4-mm diameter implant and 7 mm for a wider diameter of 5-mm implant. Posterior mandibular dental implant should be planned so that the exit angle of the screw access points toward the inner incline of the palatal cusp. Posterior maxillary implants should be placed so that the exit angle of the screw access points toward the inner incline of the buccal cusp. Clinical evaluation of the occlusogingival space can be evaluated under crown height space availability. Sufficient crown height space must exist for harmonious aesthetic and functional replacement with the adjacent teeth. On clinical examination, the space between the residual ridge and the opposing occlusal plane should be evaluated. For instance, if replacing the premolar and molar teeth, a space of 10 mm must exist between the residual ridge and the opposing occlusion. A 7-mm space would be considered the minimum space required. In situ ations where the opposing teeth overerupt and compromise the prosthetic space, enameloplasty or minimal restorative therapy, orthodontic intrusion, elective endodontics, crown lengthening, and full coverage of the crown may be required to create space.[6],[7]
Evaluation of the soft tissue ridge support
The health or quality of the soft tissue influences harmonious aesthetic outcomes in dental implant rehabilitation. The supracrestal soft tissue constituting the papillae positioning influences the harmony between the new prosthesis, the remaining teeth, and the surrounding soft tissues. Classically, soft tissue topography is determined by parameters such as contact point position, crown dimensions, tooth implant distances, and implant diameter. The assessment of keratinizing mucosa that surrounds the adjacent teeth is thought to be a positive factor in maintaining the health of the soft tissue around the dental implant. Enough space between the implants is needed to allow interdental papilla reconstruction or at least soft tissue preservation. When the space between the dental implants is too close, insufficient blood supply may result in papilla collapse and when the dental implants are placed far apart, unsupported inter-implant papilla may collapse. The contour of the ridge, along with the height and width, can be visually inspected and carefully palpated. The presence of concavities, particularly on the facial aspect, is detected with ease. However, accurate assessment of the underlying bone dimension is clinically difficult when the overlying tissue is fibrous, especially on the palate where the tissue palpated may be of thick variant and can result in pseudo-impression of the healthy bone profile.[5],[6]
Ridge mapping
Techniques such as ridge mapping may clinically help in assessing the bone profile. The area of concern is assessed under local anesthesia and the thickness of the soft tissue is measured by puncturing through to the bone, using either a graduated periodontal probe or specially designed callipers. The same information is then transferred to a diagnostic cast that is sectioned through the ridge. This method provides a better indication of the bone profile than simple palpation but error is inevitable. Whenever evaluation of the bone width and contour is critical, radiographic assessment is advised.[2]
Ridge angulation
The relationship of ridge angulations and the opposing dentition is important to assess. The available distance should be measured to ensure adequate room for the prosthetic components. Proclined and retroclined ridge forms tend toward angled implant placement that could affect the aesthetics and loading protocol. Large horizontal discrepancies between the jaws, for example, the pseudo class III jaw relationship following extensive maxillary resorption is not suitable for treatment with fixed bridges. The clinical examination of the ridge also allows assessment of the soft tissue thickness that is important for the attainment of good aesthetics. Keratinized tissue that is attached to the edentulous ridge provides a better peri-implant soft tissue than nonkeratinized mobile mucosa. The length of the edentulous ridge can be measured to give an indication of the possible number of implants that could be accommodated in the edentulous span. However, this also requires reference to radiographs to allow a correlation with the available bone volume and the diagnostic setup for the proposed tooth location. In partially edentulous ridges bound by teeth, the available space is affected by angulations of the adjacent tooth roots, which may be palpated or assessed radiographically.[7]
If the height or width of the recipient ridge areas is inadequate or the trajectory is unsatisfactory, an implant may not be feasible. Bony undercuts also present problems as do the positions of anatomic features, such as the mental foramen. If the ridge is inadequate for any reason, an implant is inappropriate and alternatives should be considered.[6],[7]
Assessment of periodontal status
A complete periodontal examination is considered to be an appropriate screening tool. The best way to clinically assess the implant site is preextraction evaluation of the failing tooth [8],[9],[10] [Figure 4]. An understanding of the associated anatomical structure is essential. The ultimate predictability of the implant site may be determined by the patient's presenting anatomy more than the clinician's ability to manage the state-of-the-art procedures. The factors that need to be considered include relative tooth position and location, form and type of the periodontium, natural teeth periodontal condition, and available ridge defect classification (Seibert's classification).
Understanding the biological principles for achieving healthy soft tissue surrounding a dental implant is essential for health, function, and aesthetics. Formation of a biological connection between the hard and soft living tissues start during tooth development and that has to be created during the healing process after placement of the implant. The aesthetics of dental implant prosthesis depend on the health and stability of the peri-implant mucosa. Understanding of soft tissue healing and maintenance around the dental implants are of paramount importance for implant success. Hence, an assessment of suitable implant site(s) based on soft tissue profile is a must during treatment planning and therapy.[4] Gingival biotype has been described as one of the key elements for a successful treatment outcome in implant dentistry. It has been suggested that the presence of papilla between the immediate single tooth implants and the adjacent teeth is correlated with a thick-flat biotype. Moreover, more gingival recessions at the immediate single tooth implant restorations have been noted with a thin scalloped biotype. A thick gingival biotype is a desirable characteristic that positively affects the aesthetic outcome of an implant restoration because a thick tissue biotype is more resistant to mechanical and surgical insults. Based on the current literature, thick gingival biotype is geared up against thin gingival biotype variety as the thicker biotype available with a thick labial plate potentiate regeneration around the implant by holding the bone graft and soft tissue graft in position, enhancing primary wound closure, enhancing revascularity, and protecting the site. Moreover, resistant to mucosal recession or mechanical irritation, better peri-implant soft tissue depth can be achieved that is better at concealing the titanium/metal margin and is more accommodating toward a different implant position and the resultant abutment angulation. Although in cases with thin biotype variety, the selection of abutment provides more concerns due to its inability to be a barricade to conceal the titanium/metal margin and it being highly prone to mucosal recession on irritation/insult. Hence, for thin tissue phenotype variety, minimally invasive or flapless surgery is more appealing because it minimizes or compromises the blood supply of the underlying bone and decreases the risk of recession after implant placement.[4],[5]
Occlusal considerations
Masticatory forces achieved by implant-supported restorations are considered to be equivalent to natural dentition. When clinically assessing a case for implant-supported restorations, a general assessment of the load to be placed on the dental implants should be made. If the patient is a bruxer, the clinician may plan additional implants to allow for more favorable load distribution. Unlike natural teeth, osseointegrated dental implants are without an intervening periodontal ligament and the mean axial displacement is noted to be approximately 3-5 µ when compared to 25-100 µ range of motion of teeth in the socket. The range of motion of osseointegrated implants has been reported to show deflection in a linear and elastic pattern and movement of the implant under the load is dependent on the elastic deformation of the bone. There are studies supporting the finding that implants are more susceptible to occlusal overloading than natural teeth, that is, displacement of a tooth begins with an initial phase of periodontal compliance that is nonlinear and complex followed by a secondary movement phase occurring with the engagement of the alveolar bone. The occlusion should be evaluated and organized so that there is anterior guidance and disclusion of the posterior teeth. There should be no contact of the posterior teeth with the nonworking sides. If the canine is compromised, group function is acceptable.[11]
| Conclusion | | |
The clinical assessment of a candidate for implant therapy follows several conventional criteria from the evaluation of temporomadibular joint to prognosis of the failing tooth to the available residual alveolar ridge. This initial evaluation possibly determines the final decision for implant case selection/placement. However, the final treatment strategy is largely dependent on the anatomical limitations, expectations/desires, and financial requirements.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
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