Category Archives: Contemporary Implant Dentistry Edwin

Soft Tissue-to-Implant Interface

Soft Tissue-to-Implant Interface

The successful dental implant should have an unbroken, perimucosal seal between the soft tissue and the implant abutment surface. To maintain the integrity of this seal, the patient must maintain a high level of oral hygiene

Initial implant stability can be aided if implant can e two cortical plates o~!:;

Initial implant stability can be aided if implant can
e two cortical plates o~!:;

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specific to dental implants. Clinicians, dental hygienists. and patients must understand and appreciate the necessity for a comprehensive implant maintenance program, including regularly scheduled recall visits. In the natural dentition the junctional epithelium provides a seal at thebase of the gingival sulcus against the penetration of chemical and bacterial  ubstances. It has been demonstrated that epithelial cells attach to the surface of titanium in much the same manner in which the epithelial cells attach to the surface of the natural tooth, that is, through a basal lamina and by the  ormation of hemidesmosomes. The connection differs from thatoccurring with natural teeth at the connective tissue attachment level. In the natural dentition, Sharpey’s fibers extend from the bundle bone of the lamina dura
and insert into the c ementum of the tooth root surface.Because no ementum or fiber insertion is found on the  surface of an endosseous implant, the epithelial surface attachment is all-important. If this seal is lost, the periodontal pocket can extend directly to the oSseous structures.
Therefore if the seal breaks down or is not present,the area is subject to periirnplant gingival disease. Although the abutment-to-junctional epithelium attachment is not mechanically strong, it is adequate to
resist bacterial invasion with the assistance of adequatehome care. When implants are stable and they have a highly polished titanium collar transversing the tissue, gingival and periimplant health appear relatively easy to maintain. The lack of definitive gingival connective tissue
attachment appears to be less of a problem in osseointegrated implants than it was in impiants with fibrous corinective tissue attachments. Because osseointegrated implants have a different relationship between theimplant and bone, there appears to be different rnecha- . nisms working against nflammation caused by bacteria and their by-products. The pathogenicity of the bacteriaseems to be particularly diminished in the ompletelyedentulous patient restored with dental implants. Diseaseactivity around the natural dentition in the partially edentulous patient may contribute to a slightly higherincidence of periimplant disease in these patients.Implant survival depends on proper and timely homecare and maintenance. The dentist must ensure that thepatient receives thorough instruction in maintenancetechniques. The goal of implant maintenance is to eradicate microbial populations. Recall visits should be sched-
.uled at least ,every ;3 months for the first year, The sulculararea should be debrided of calculus by’ using plastic Dr wooden scalers. A rubber cup with low abrasive polishing paste or tin oxide may be used to polish implant abutments. Implant mobility should be evaluated and bleedingupon probing documented. Framework fit and occlusion should also be checked at recall appointments. These biomechanical factors are as important as oral hygienefor the long-term success of the dental implant.

BIOLOGYIC CONSIDRITION FOR OSSEOINTERATION

BIOLOGYIC CONSIDRITION  FOR OSSEOINTERATION

the discovery of methods to maximize the amount of # bone and implant contact. Osseointegration ‘is a histologic definition meaning “a direct connection between living bone and load-bearing end osseous Implant at the
light microscopic level.” Four main factors are required to achievesuccessful osseointegrated bone-to-implant interface: (1) a biocompatible material, (2) an implant precisely adapted to the prepared bony site, (3) traurnatic surgery to minimize tissue damage, and (4) an Irnrnobile, undisturbed healing phase. A biocompatihle material is necessary to promote healing without a foreign-body rejection reaction by the host tissue:lf biocompatible materials are not used, the body attempts to isolate theforeign-body plant material by surrounding it with granulation and then connective tissue. It has been.

BOX 14-1 .

Generally Accepted Implant Success Criteria

‘l. The individual unattached implant is immobile whentested clinically.
2. No evidence of periimplant radiolucency is present,
as assessed on an undistorted radio graph.
3. The mean vertical bone loss is less than 0.02 mmannually after the first year of service.
4. No persistent pain, discomfort, or infection is attributable to the implant.
5. The ‘implant design does not preclude placement of,a crown or prosthesis with .an appearance that is satisfactory to the patient and the dentist.

From Smith D, Zarb GA: Criteria for success for osseointegrated end osseous implants, J Prosthet Dent 62:567, 1989.

demonstrated that titanium and certain calciurn-phosphate ceramics are both biologically inert. The size of the gap between the implant and the bone immediately after implant placement is critical to achieving
osseointegration. The gap size can be controlled primarily by the preparation of a precise surgical bed into which the Implarrt is placed. Cylindrical preparations are the mostpredictably made in an accurate shape. Precision instrumentation and a technically sound surgical procedure minimize the distance between the implant and host bone.
Atraumatic surgery is required to allow minimal mechanical ‘and thermal injury to occur. Sharp, highquality burs that are run at low speed by high-torque  drills are essential to precise atraumatic bed preparation.
Copious irrigation by either internal or, external methods keeps the bone temperatures to Ievels below S6° C, which is the level beyond which irreversible bone damage occurs. It has been also found that bone tissue damage  occurs when the bone temperature reaches 47° C for more than 1 minute. If the temperature rises, alkaline phosphatase within the bone is denatured, which prevents alkaline calcium synthesis. If the gap between the implant and the bone can be minimized and surgery isatraumatic, embryonic bone will rapidly be laid down between the implant and the bone and WIll ihen mature into the lamellar load-bearing bone (Fig. 14-6).
Implant immobility during the healing phase is affect-.ed by bone quality and quantity. Areas of the jaws that have a high percentage of cortical
bone, such as the anterior mandible, are more likely to anchor the implant successfully. Areas of the jaws with a high percentage of cancellous bone make initial stability for the implant more difficult to achieve. It is also
advantageous for init ial implant stability if both the superior and inferior cortical plates can be used to stabilize the implant (Fig. 14-7), which is frequently possible in the anterior mandible and the maxilla. However, the
inferior alv, .lar can al prevents this from occurring in theposterior mandible.

FIG. 14-6 A, Implant site prepared in bone using irrigation to keep temperatures below 47~ C to prevent cell death in area. B, Precisely machined implant placed in' site. Gap between implant and bone should be less than 1 mrri: (,-If gap between implant and bone is small enough, embryonic bone will rapidly bridge gap. D, If implant is left undisturbed during healing phase, embryonic bone will ~ture to lamellar load-bearing bone.

FIG. 14-6 A, Implant site prepared in bone using irrigation to keep temperatures below 47~ C to prevent
cell death in area. B, Precisely machined implant placed in’ site. Gap between implant and bone
should be less than 1 mrri: (,-If gap between implant and bone is small enough, embryonic bone will
rapidly bridge gap. D, If implant is left undisturbed during healing phase, embryonic bone will ~ture
to lamellar load-bearing bone.

Once the initial stability of the implant has been  acruevcd. it must be maintained throughout the healing phase. Should the patient desire to continue to wear the removable prosthesis during the healing period, it is
important that a soft liner be placed in the removable denture to further decrease load transfer to the implant. The bone in the mandible is generally denser than the bone inthe maxilla. Therefore because the maxilla is primarily cancellous bone, osseointegration requires a longer healing
period. When placing implants, it is crucial to obtain primary stabilization for successful osseointegration. The achievement of successful  sseointegration is first assessed at the second -surgery. Once- the abutment is attached to the implant body, the surgeon should carefully ch eck for any signs Of clinically detectable mobility An immobile implant at this stage indicates successful osseointegration. Detectable mobility at this stage indicates that fibrous connective tissue has encapsulated the implant. If mobility .s detected, the implant should be  removed at that time. The failed site is allowed to heal and another implant can be placed at a later time.  once – a successful osseointegrated bone-to-implant interface . has been achieved, masticatory function at least equal that of natural dentition is generally possible. The major mechanisms for the destruction of osseointegration are similar to those’ of natural teeth. Disease activity in the periimplant soft tissue environment and biomechanical overload of the individual implant are the two factors most commo~11 associated with the potential breakdown of osseointegration.

Contemporary Implant Dentistry Edwin

CHAPTER OUTLINE

BIOLOGIC CONSIDERATIONS FOR OSSEOINTEGRATION
Soft Tissue-to-Implant Interface
Biomechanical Factors Affecting long-Term Implant
Success
CLINICAL IMPLANT COMPONENTS
Implant
Cover Screw
Healing Cap
Abutment
Impression Post
Laboratory Analog
Waxing Sleeve •
Prosthesis-Retaining Screw
IMPLANT PROSTHETIC OPTIONS
Completely Edentulous Patients
Implant- and Tissue-Supported Overdenture
All Implant-Supported Overdenture
Fixed Detachable Rest~ration
Partially Edentulous Patients
Free-End Distal Extension
Single-Tooth Implant Restorations
PREOPERATIVE MEDICAL EVALUATION OF IMPLANT
PATIENT
SURGICAL PHASE: TREATMENT PLANNING
Evaluation of Implant Site
Bone Height, Width, and Anatomic limitations
Informed Consent
Surgical Guide Template
BASIC SURGICAL TECHNIQUES
Patient Preparation
Soft Tissue Incision
Preparation of Implant Site
Implant Placement
Postoperative Care
Uncovering
COMPLICATIONS
Failing Implant
ADVANCED SURGICAL TECHNIQUES
Guided Bone Regeneration
Block Bone Grafting
Alveolar Distraction
Transantral Grafting (Sinus Lift)
SPECIAL SITUATIONS
Postextraction Placement of Implants
Anterior Maxilla Esthetic Zone
Atrophic Anterior Mandib.le
.II< Atrophic Posterior’ Mandible
Atrophic Max.illa
Implants in Growing Patients
“Implants in Irradiated Bone
Early Loading
Extraoral Implants
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The  dentalconsiderable clinical skill Whelp patients cope wit11 the
. . effects of partial or co mplete cdentulism. Dental problems that were historically the most difficult can be solved today with the assistance of dental Implants . . Completely edentulous patients now enjoy the security
and function of fixed restorations (Fig. 14-1). Patients missing a posterior abutment, who would ordinarily require a distal extension. removable partial denture, may now enjoy the benefits of a fixed restoration with
dental implants (Fig. 1-1-2). Trauma victims who -are missing teeth and bone can be successfully rehabilitated with fixed restorations (Fig. 14-3). Even the patient missingonly a single tooth can receive a restoration more
analogous to the missing natural tooth (Fig. 14-4). Likewise, a patient with the available bone can receive a complete fixed implant rchabilitatlon (Fig. 14-5). These examples illustrate advantageous and predictable alternatives
to ,edentulism tl1at arc becoming the standar-d of care within the dental community. The dental profession has not always’ had a positive opinion of dental implants. Implants had their beginnings.around the middle ‘of the twentieth century. Early types of dental implants came into relatively common1I~l’ during till’ 19()()s because of patient demand,

tlG. 14-1 Complete-arch implant restoration supported by five implants-in completely edentulous patient

tlG. 14-1 Complete-arch implant restoration supported by five
implants-in completely edentulous patient

FIG. 14-2 Radiograph of two-unit implant restoration used to restore dentition. Conventionally, replacement with removable -partial denture would be required.

FIG. 14-2 Radiograph of two-unit implant restoration used to
restore dentition. Conventionally, replacement with removable -partial
denture would be required.

although little or no scientifically sound research had been done to characterize implant success rates. In a 19~2 conference held in Toronto, the North American dental profession was .introduced to a body oi scientific literature on Swedish research into the bone- oimplant interface-a concept called osseointegration. This new conce pt is based on atraumatic implant placement and delayed implant loading. These factors contribute to a remarkably higher degree of implant predictably than was previously possible. The Swedish research team led by p. l. Branemark reported high success in the mandible for over 15 years. The knowledge gained from the experience of the Swedish team was used in the development of other systems currently available. on’ the market, Today
the American Dental Association (ADA) has also accepted many other systems. “In 1988 a National Institutes of Health (NIH) consensus conference was held in Washington, D.C. This conference
evaluated term long-term effectiveness ‘of dental implants ami established indications and contraindications for the various types of dental implants. Stnngcnt criteria for success were proposed and have gained general
acceptance (Box 14-1), By these criteria a success rate of 85% at the end of a 5-year observattothe end of a l Ovyear-period are minimal levels for sucess.

fiG. 14-3 A, Twenty-six-year-old patient with large dental defect rilused by shotgun wound, Three Irnplants placed in defect. B, Trau-' matic defect restored with implant-supported hybrid restoration retained by screws

fiG. 14-3 A, Twenty-six-year-old patient with large dental defect
rilused by shotgun wound, Three Irnplants placed in defect. B, Trau-‘
matic defect restored with implant-supported hybrid restoration
retained by screws

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FIG. 14-4 A, Thirty-year-old patient with missing mandibular premolar. Sinqle dental implant has been placed in extraction site. Abutment projects througb soft tissue. 8, Single-tooth implant restored without comprornlsinq adjacent tooth structure.

FIG. 14-4 A, Thirty-year-old patient with missing mandibular premolar. Sinqle
dental implant has been placed in extraction site. Abutment projects througb soft
tissue. 8, Single-tooth implant restored without comprornlsinq adjacent tooth
structure.

FIG. 14-5 Radiqgraph of complete-mouth fixed implant restoration .

FIG. 14-5 Radiqgraph of complete-mouth fixed implant restoration .