Once an implant is placed, there are three loading protocols that may be used. An implant loading protocol is defined as the time elapsed between implant placement and the attachment of the prosthesis so that the implant is brought into function. Conventional loading of dental implants is defined as loading 2 or more months after implant placement. This is a well-established protocol that allows for complete healing of bone and peri-implant soft tissues prior to prosthesis attachment. In an early loading protocol, the prosthesis is attached between 1 week and 2 months subsequent to implant placement. The implants are put into function during the later stages of bone healing but prior to complete healing of soft tissues. This results in a relatively reduced treatment time between implant placement and loading compared to the conventional loading protocol. In contrast, immediate loading of dental implants is defined as prosthesis attachment within 1 week of implant placement, including the day of surgery. In this case, the process of peri-implant bone and soft tissue healing occurs with the provisional prosthesis attached to the implant from the outset.

Immediate loading - in which the prosthesis is attached at or soon after implant placement - has the greatest potential to shorten the overall treatment time for the patient. However, the quest for quicker treatment may increase the risks of complications and failure, so the clinician must be aware of the risks involved. Therefore, the aim of this module is to review the concept of immediately restoring an implant after surgical placement and to outline the indications and contraindications for this treatment approach.

After completing this ITI Academy Module, you should be able to: define the terms immediate restoration and immediate loading; list the prerequisites for immediate restoration and loading; describe the advantages and disadvantages of immediate restoration and loading; and list the indications for immediate restoration and loading.

'Immediate loading' is a term that includes two distinct but interrelated concepts: the 'restoration protocol' and the 'loading protocol'. This is illustrated in the following diagram. The restoration protocol refers to the point at which a prosthesis is attached onto an implant after it has been surgically placed. 'Immediate restoration' is defined as a provisional prosthesis that is attached to an implant or implants within 1 week of implant placement. The loading protocol is then determined by whether functional occlusal contacts on the prosthesis can be avoided or not. It is usually preferred to avoid functional occlusal contacts with an immediate restoration whenever possible. This can usually be achieved in single-tooth and short-span cases where functional occlusal contacts can be provided by the neighboring teeth. The provisional prosthesis is said to receive 'no loading' during the integration period. If the immediate restoration is in full functional contact with opposing teeth, this is referred to as 'immediate loading'. Immediate loading occurs in cases of full-arch and extended edentulous spans, where functional contacts cannot be avoided due to the lack of natural teeth.

The following clinical case fulfills the definition of immediate restoration, as the provisional prosthesis was connected within 1 week of implant surgery and there were no functional occlusal contacts. The implant was placed immediately after tooth extraction and was inserted with adequate primary stability. A provisional prosthesis was fabricated and attached to the implant on the same day as the implant surgery. The occlusal view shows that the provisional prosthesis received no loading, as there were no functional occlusal contacts with the opposing lower incisors. Although occlusal forces may be avoided in immediate restoration cases, it is important to highlight that the action of the oral musculature - such as the tongue, lips, and cheek, as well as interposed food when chewing - will result in forces being directed onto the implant. This must be taken into account for safe utilization of this protocol.

This case represents the definition of immediate loading, as the provisional prosthesis was connected within 1 week of implant surgery and was in full functional occlusal contact with the maxillary teeth from the outset. Five implants were placed in the anterior region of the mandible. After connection of abutments to the implants, a full-arch provisional prosthesis was inserted, supported by the five implants. The marks on the occlusal surface of the prosthesis made by articulating paper indicate that the prosthesis was in functional occlusal contact with the opposing dentition. In full arch-cases, multiple posterior contacts in centric occlusion and a balanced dynamic occlusion are recommended.

In immediate restoration and immediate loading, it is recommended that a provisional prosthesis be used. Ongoing modifications are often necessary during the early healing phase after implant placement. A provisional prosthesis allows the clinician to readily modify the shape, profile, and occlusion prior to the final impressions for the definitive prosthesis. Is also recommended that there be a period of undisturbed healing post-implantation to allow adequate healing of the hard and soft tissues in contact with the implants and the prosthesis. The clinician should avoid removing the provisional prosthesis as far as possible during this time, as this could result in excessive movement of the implants, which could in turn jeopardize osseointegration. The period of undisturbed healing varies depending upon the case and the clinician's estimation of the time for the implants to integrate and the soft tissue to heal, but as a general rule this should not be less than 6 to 8 weeks. Once the osseointegration is confirmed, soft tissue conditioning can begin. The provisional prosthesis is modified by adding or removing material in certain areas to obtain an adequate emergence profile and mucosal architecture that suits the design of the definitive prosthesis. This step is vital in fixed dental prostheses, where the soft tissue contour plays an important role in esthetics and access for homecare and maintenance. After soft tissue conditioning of about 4 months for single-tooth implants and 6 months for multiple adjacent implants, the definitive prostheses may then be delivered.

This concept is illustrated in the following clinical case. The implants were placed in the ideal positions according to a prosthodontically driven treatment plan using a surgical template. Next, screw-retained provisional abutments were placed in the implants, and the provisional prosthesis was tried in. It is important to confirm correct seating of the prosthesis before it is affixed to the abutments using acrylic. Note that the acrylic portion covering the palate in the right image helps the prosthesis to seat correctly. This portion will be removed when the prosthesis is trimmed up and finalized ready for fitting. In either case, acrylic resin is added to affix the provisional prosthesis to the abutments and to pick them up together.

After 8 weeks of healing, the provisional prosthesis was modified to create an adequate soft tissue framework for the definitive prosthesis. After 8 months of soft tissue conditioning by altering the shape and contour of the prosthesis, the soft tissues are suitable for final impressions, and the definitive ceramic bridges are delivered. Please note the scalloping of the soft tissues, which gives the appearance of interdental papillae.

Definitions, Key Learning Points: Immediate restoration is defined as the connection of a provisional prosthesis within 1 week of implant placement. Immediate loading is defined as an immediate restoration in full functional occlusal contact. Immediate restoration without functional occlusal contacts can only be achieved in single-tooth or short spaces. Immediate restoration with immediate loading occurs in extended spaces or full-arch cases. A minimum of 6 to 8 weeks of undisturbed healing is recommended before commencing soft tissue conditioning for both non-loaded and immediately loaded situations.

A critical prerequisite for immediate restoration and loading is the selection of implants of sufficient length with a surface that encourages osseointegration. Implants between 8 and 11 millimeters in length are ideal for this purpose. The placement of implants less than 8 millimeters in length increases the risk of micromovements that may jeopardize osseointegration. Conversely, implants longer than 11 mm can be used, but there is the added risk of overheating the bone during preparation of the osteotomy prior to implant insertion. Extra care needs to be taken with longer implants to ensure that the site preparation does not overheat the bone. The macro design of an implant plays an important role in achieving primary stability and force distribution in the early stages of healing. Thus, threaded implants are recommended. Tapered-design implants may also increase implant stability, specially in low-density bone.

The clinician should select an implant with a surface that is conducive for rapid osseointegration. An optimal surface will shorten the osseointegration time, create better conditions for bone apposition, and increase bone-to-implant contact at later healing stages. As a general recommendation, implants with a microroughened surface between 1 and 2 microns and which have evidence for rapid osseointegration should be selected.

When an implant is immediately restored or loaded, there is a risk that movement of the implant could prevent it from successfully integrating with the surrounding bone. Excessive movement may result in the implant becoming encapsulated in fibrous tissue rather than integrating with the bone. In an experimental study, implants that were unstable at the time of placement failed to achieve osseointegration. A layer of loose fibrous connective tissue was present between the implant surface and the newly regenerated bone. This radiograph shows a case where the implant failed to integrate after it was placed. A radiolucent space can be observed between the implant and the surrounding bone throughout the length of the implant, suggesting the presence of interposed fibrous connective tissue. Although there are no precise recommendations for what the threshold of this movement might be, studies have suggested that micromovement in the range of 50 to 150 microns can be tolerated and indeed, may be beneficial to the integration process. From a practical point of view, it is not possible to measure small degrees of micromovement in a clinical setting. Therefore, it is recommended that the clinician plan the treatment and design the prosthesis to minimize micromovement of any implant for which immediate loading and/or immediate restoration is being planned.

For an implant to be used in an immediate restoration and loading protocol, it is recommended that the implant achieve a final insertion torque between 30 and 45 Ncm. Implants placed with less than 30 Ncm of torque may be subjected to higher degrees of micromovement, which may affect osseointegration. If implants are placed with torque greater than 45 Ncm, there is a significant risk of trauma to the bone, which could result in microfractures. Excessive torque can lead to early implant loss. The clinician can measure the achieved stability at final seating of the implant using a number of measures, including manual ratchets and digital instruments that provide measures of stability such as the Implant Stability Quotient, or ISQ, and the Periotest value, or PTV. The device shown in the image at right uses resonance frequency analysis to quantify implant stability. Magnetic pulses from the probe cause a peg attached to the implant to vibrate like a tuning fork. Measuring the resonance frequency of the peg provides an estimation of the stiffness in the interface between the implant and the bone. The result is presented as an ISQ value from 1 to 100. The higher the ISQ value, the more stable the implant. The ISQ reading of 82 recorded for this implant indicates a high degree of stability.

Another important prerequisite for immediate restoration and loading is to ensure that the implant is placed in the correct three-dimensional prosthodontic position. In doing so, not only will the implant be correctly positioned and framed by the surrounding hard and soft tissues, but forces will also be transmitted along the long axis of the implant. In immediate loading and restoration, forces transmitted predominantly through the long axis of the implant cause less micromovement than forces transmitted non-axially. The design of the provisional prosthesis should conform to the predetermined prosthodontic plan.

Clinicians should be very cautious in recommending immediate restoration and loading in patients with a history of occlusal parafunction. Patients with parafunctional habits can generate significant non-axial forces on the natural teeth as well as on the implant prosthesis. It is therefore recommended that patients with evidence of occlusal parafunction should not be selected for immediate restoration and loading protocols. It is also recommended that patients requiring bone grafting either for lateral ridge augmentation or sinus floor augmentation should not be selected for immediate restoration and loading.

Prerequisites for Immediate Restoration and Loading, Key Learning Points: An optimal length, design, and surgical protocol are important factors for implant survival. An implant surface treatment will shorten the osseointegration time. Excessive micromovements during the osseointegration phase should be avoided. Primary stability between 30 and 45 Ncm is recommended. Implant 3D positioning has a strong impact on force distribution and prosthetic design. It is not recommended to combine immediate loading with bone grafting and/or parafunctional habits.

Provided that appropriate cases are correctly identified and that the prerequisites for successful outcomes during treatment are achieved, immediate restoration is predictable in several clinical indications, including single-tooth replacements, short spans, and edentulous arches. These clinical indications will be detailed later in this module.

Another advantage of immediate restoration is that osseointegration of the implants takes place together with initial contouring of the soft tissues, which adapt to the shape of the provisional prosthesis. The soft tissue conditioning is said to be passive because healing progresses undisturbed and no adjustments are made to the provisional prosthesis in this early healing phase. Passive conditioning of the soft tissues is illustrated in this clinical case. 48 hours post-implantation, the provisional prosthesis is attached, which initiates the transmission of occlusal forces to the bone-implant interface. Once the implants have integrated, active conditioning of the soft tissues takes place during modification of the shape of the provisional prosthesis.

One significant advantage of immediate restoration relates to the comfort of the patient during treatment. Immediate restoration avoids the need for removable or bonded interim prostheses. Interim prostheses include vacuum-formed removable prostheses, acrylic removable prostheses, and resin-bonded bridges. Removable interim prostheses are inconvenient for the patient and may interfere with speech and function. They can sometimes cause pain if they are overextended and often require ongoing modification during the healing period.

Immediate loading is not applicable in all clinical cases. In order to achieve a successful outcome, the clinician must carefully select the patient and case type to ensure that the clinical conditions are favorable for an immediate loading protocol. Each case needs to be evaluated individually and the correct protocol recommended. This requires a structured approach to assessment and treatment planning, commencing with a detailed clinical examination and three-dimensional radiographic assessment. Additional investigations should include diagnostic set-ups using articulated models to evaluate the occlusion more thoroughly. With this information, a diagnosis of the underlying problems can then be made, which in turn allows the clinician to assess the risk of the different treatment approaches that may be considered. If immediate loading is considered, the prerequisites for successful outcomes as described in the previous section must be fulfilled.

There are a number of disadvantages to immediate loading that need to be considered. It is generally recognized that a high level of clinical skill and experience is required to undertake the diagnosis, case selection, and treatment required for immediate loading protocols. In this clinical example, advanced clinical skills and experience were required to treat the case. Following extraction of the mandibular incisor teeth, the alveolar bone had to be reduced in height and reshaped to provide a flat surface prior to the insertion of implants. This required elevation of mucoperiosteal flaps and careful extraction to avoid bone fractures. An optimal degree of stability of the implants had to be achieved to carry out the planned immediate loading of the implants. Finally, the prosthodontic steps of impression taking, transference and registration of the occlusion, and fabrication and delivery of the provisional prosthesis needed to be performed accurately. Thus, several surgical and prosthodontic steps had to be undertaken sequentially to manage the case appropriately.

Occlusion is a key element in dental implantology, but it is particularly important in immediate loading of full-arch rehabilitations. The vertical dimension of occlusion (or VDO), centric occlusion, and the occlusal plane must be evaluated in the diagnostic phase, modified if necessary, and then incorporated into the treatment plan. The planned occlusion must then be maintained during the surgical and prosthodontic phases. In immediate loading, the implants will be subjected to functional and parafunctional forces as soon as the provisional prosthesis is attached. Therefore the occlusion should be designed to distribute the forces as evenly as possible. The best way to achieve this is to obtain several occlusal contacts harmoniously distributed that direct forces axially through the implants to avoid excessive micromovements. For dynamic occlusion, the recommendation is group function where possible without interferences during excursive or protrusive movements. The aim is to reduce non-axial forces both on the implants and on the screw-fixation components of the prostheses.

Implant treatment is interdisciplinary and involves three disciplines: surgery, prosthodontics, and the dental laboratory. In immediate loading protocols, the interdisciplinary relationships are closely integrated, and treatment steps need to be executed in a relatively short time frame. This increases the complexity of treatment and requires clinicians from the various disciplines to allocate and coordinate clinical and laboratory time, and to work closely together in both the diagnostic and treatment phases. The following case illustrates the planning required. Based on the clinical and radiographic assessment, the implant positions are planned from both a surgical and a prosthodontic perspective whilst at all times maintaining the concept of prosthodontically driven treatment planning. During the surgical phase the prosthodontic plan must be communicated to the surgeon through the use of surgical templates. In this case, it can be seen that the five implants have been precisely placed according to the surgical template. This subsequently assists in the next phase, which is fabrication and attachment of the provisional prosthesis. In order to carry out immediate loading with a high level of predictability, the clinician needs to structure and organize the practice to allow for interdisciplinary treatment planning and management.

Advantages and Disadvantages, Key Learning Points: Advantages of immediate restoration and loading are that: it is predictable in specific clinical indications; osseointegration and passive soft tissue contouring take place at the same time; and there is less postoperative inconvenience due to a removable or fixed interim prostheses. Disadvantages of immediate restoration and loading are that it requires: careful patient selection; a high level of clinical skill and experience; precision in occlusal management; and interdisciplinary planning and organization.

In this section, the indications for immediate restoration and immediate loading will be presented. There is a high level of evidence to support immediate restoration of single implants in anterior sites, provided cases are correctly selected and the provisional prostheses do not receive functional occlusal loading. In these cases, the literature reports similar implant survival and radiographic marginal bone changes compared to early and conventional loading protocols. In maxillary anterior sites where esthetic demands may be high, this treatment approach should be adopted with caution due to the risk of adverse esthetic outcomes. Immediate restoration of single implants in anterior sites should only be undertaken by experienced clinicians. According to the ITI SAC classification, immediate restoration for single implants in anterior sites is 'Complex'.

In this clinical case, a young patient with thick biotype presented with traumatic avulsion of a central incisor. A single implant was placed and immediately restored with a single crown with the absence of any occlusal contacts. Once osseointegration and optimal soft tissue architecture was achieved, the definitive prosthesis was delivered.

For single implants in posterior sites, the evidence for successful outcomes differs for the maxilla and mandible. In the mandibular molar region, immediate restoration of single implants is a predictable procedure. However, there is often not a strong clinical indication to adopt this approach in mandibular posterior sites. Therefore this approach should be adopted only where clinical benefits can be identified, for example, to prevent migration of adjacent teeth. In contrast, there is not enough evidence to support immediate restoration of implants for single teeth in the posterior maxilla. The clinician should exercise caution if adopting this approach in this region of the maxilla. According to the ITI SAC classification, immediate restoration in single-tooth posterior sites is 'Complex' and should only be undertaken by experienced clinicians.

In this clinical example, orthodontic treatment was undertaken to upright a mesially tipped second molar and to create more mesiodistal space in the first molar edentulous site. The first molar had been missing for many years. As soon as the second molar was correctly positioned, an implant was placed in the first molar site. An immediate restoration protocol was utilized to maintain the created mesiodistal space and to prevent relapse tipping of the second molar. The final image shows the ceramic crowns 2 years after implant placement. There has been some recession of the mucosa on the buccal aspect as compared to the soft tissue levels at the gingival margins of the adjacent natural teeth, most likely as a result of a relatively thin buccal plate of bone at the time the implant was placed. The definitive crown has been constructed to mimic gingival recession.

Immediate restoration and loading protocols have relatively low levels of evidence to support this treatment approach in sites with adjacent multiple missing teeth. In anterior sites, there is currently insufficient evidence to support immediate restoration and immediate loading protocols. If this treatment approach is utilized, the clinician must be aware of the potential for complications and adverse outcomes. In posterior sites, there is more evidence to support immediate restoration and loading. The literature indicates that this approach seems predictable. However, the clinical benefits for adopting this approach are limited, and it should only be recommended if clear clinical advantages can be identified. When there are multiple missing teeth in a partially edentulous patient, the potential for overloading implants in the early healing phase is increased. Therefore, to minimize risk implants of adequate length and microroughened surfaces should be placed with adequate primary stability. As in previous indications for immediate restoration and loading, the ITI SAC classification considers this treatment approach for adjacent multiple missing teeth to be 'Complex'.

In this clinical case, two implants were placed in the second premolar and first molar sites in a maxillary posterior region, and an immediate restoration protocol was utilized. Due to a wide smile, the missing tooth spaces were visible and an esthetic concern to the patient. She could not tolerate a removable partial denture due to a strong gag reflex. 8 weeks after implant placement, the provisional prosthesis was removed, revealing the surrounding soft tissues. Note that in this situation, the provisional crowns have been splinted together and occlusal contacts have been minimized.

In the edentulous jaws of the maxilla and mandible, immediate restoration and loading with one-piece fixed provisional prostheses is supported by the literature. However, the ITI SAC classification considers this treatment approach to be 'Complex', and it should only be performed by experienced clinicians and in the correct clinical indications. When there are remaining teeth that need to be extracted at the time of surgery, the alveolar ridge should be reduced in height and flattened to create a suitable platform for locating the implants. The number of implants placed as well as their dimensions and distribution should be based on a prosthodontic plan. This plan must take into consideration local anatomic structures that may influence the position and length of the implants to be placed. Simultaneous bone augmentation procedures for either lateral augmentation or sinus floor elevation are considered to be relative contraindications for immediate loading, as they increase both the surgical morbidity and the risk of complications and failure.

This clinical example illustrates mandibular full-arch rehabilitation. After discussion of all suitable prosthodontic options, the patient chose a full-arch immediate implant-supported solution. The six remaining teeth were extracted at the time of implant placement. The immediate loading protocol allowed a fixed provisional prosthesis to be attached to the implants within 48 hours of surgery. The patient was able to function with a fixed prosthesis throughout the treatment period, which greatly enhanced the patient's comfort and well-being. This image shows the definitive zirconia and ceramic hybrid fixed prosthesis 1 year after implant insertion.

The literature for immediate loading of removable prostheses in edentulous jaws is not as strong as that of fixed prostheses in edentulous jaws. The available evidence suggests that immediate implant loading using removable prostheses is predictable in the mandible. It is recommended that at least two implants be utilized in an immediate loading protocol with a removable prosthesis. On the other hand, there is limited evidence to support this treatment in the maxilla, and therefore this treatment approach should be used with caution. If immediate loading of a maxillary removable prosthesis is considered, it is recommended that four or more implants be utilized. Regarding the type of retention used for the removable prosthesis, early evidence suggests no difference in the 1-year survival rate of implants that are splinted with a bar compared to that of unsplinted implants. As in previous indications for immediate restoration and loading, the ITI SAC classification considers the treatment of edentulous jaws with removable prostheses to be 'Complex'.

Indications for Immediate Restoration and Loading, Key Learning Points: Immediate restoration and loading of single implants is a predictable treatment in most clinical situations and can be performed with a low level of risk. Use of an immediate protocol for multiple missing teeth in a partially edentulous patient is not strongly supported by literature. Immediate loading of fixed prostheses in edentulous patients can be recommended as a safe procedure. Immediate loading of removable prostheses in the mandible is supported by literature, whereas in maxilla the evidence for this treatment is weak. In all clinical situations, general prerequisites for immediate restoration and loading protocols should be followed.

Immediate Restoration and Loading, Module Summary: Immediate restoration is defined as the connection of a provisional prosthesis within 1 week of implant placement. Immediate restoration without functional occlusal contacts is possible for single implants or short spans; immediate loading occurs in extended spaces or full-arch cases. Prerequisites for immediate restoration and loading are the selection of implants of sufficient length and design with a surface that encourages osseointegration and the placement of those implants with adequate primary stability in the correct three-dimensional position.

Advantages of immediate restoration and loading include its predictability in specific clinical indications, passive soft tissue contouring at the same time as osseointegration, and less postoperative inconvenience for the patient. Disadvantages are the requirements for careful patient selection, a high level of clinical skill and experience, precise occlusal management, and interdisciplinary planning and management.