tissue adjacent to an implant (referred to as a palatal roll) can be moved towards the lip (buccal), gingiva from the palate can be transplanted, deeper connective tissue from the palate can be transplanted or, when a larger piece of tissue is needed, a finger of tissue based on a blood vessel in the palate (called a vascularized interpositional periosteal-connective tissue (vip-ct) flap) can be repositioned to the area.: 113–188 additionally, for an implant to look esthetic, a band of full, plump gingiva is needed to fill in the space on either side of implant. the most common soft tissue complication is called a black-triangle, where the papilla (the small triangular piece of tissue between two teeth) shrinks back and leaves a triangular void between the implant and the adjacent teeth. dentists can only expect 2–4 mm of papilla height over the underlying bone. a black triangle can be expected if the distance between where the teeth touch and bone is any greater.: 81–84 recovery the steps taken to secure dental crowns on the implant fixture including placement of the abutment and crown the prosthetic phase begins once the implant is well integrated (or has a reasonable assurance that it will integrate) and an abutment is in place to bring it through the mucosa. even in the event of early loading (less than 3 months), many practitioners will place temporary teeth until osseointegration is confirmed. the prosthetic phase of restoring an implant requires an equal amount of technical expertise as the surgical because of the biomechanical considerations, especially when multiple teeth are to be restored. the dentist will work to restore the vertical dimension of occlusion, the esthetics of the smile, and the structural integrity of the teeth to evenly distribute the forces of the implants.: 241–251 healing time there are various options for when to attach teeth to dental implants, classified into: immediate loading procedure. early loading (one week to twelve weeks). delayed loading (over three months) for an implant to become permanently stable, the body must grow bone to the surface of the implant (osseointegration). based on this biologic process, it was thought that loading an implant during the osseointegration period would result in movement that would prevent osseointegration, and thus increase implant failure rates. as a result, three to six months of integrating time (depending on various factors) was allowed before placing the teeth on implants (restoring them). however, later research suggests that the initial stability of the implant in bone is a more important determinant of success of implant integration, rather than a certain period of healing time. as a result, the time allowed to heal is typically based on the density of bone the implant is placed in and the number of implants splinted together, rather than a uniform amount of time. when implants can withstand high torque (35 ncm) and are splinted to other implants, there are no meaningful differences in long-term implant survival or bone loss between implants loaded immediately, at three months, or at six months. the corollary is that single implants, even in solid bone, require a period of no-load to minimize the risk of initial failure. single teeth, bridges and fixed dentures an abutment is selected depending on the application. in many single crown and fixed partial denture scenarios (bridgework), custom abutments are used. an impression of the top of the implant is made with the adjacent teeth and gingiva. a dental lab then simultaneously fabricates an abutment and crown. the abutment is seated on the implant, a screw passes through the abutment to secure it to an internal thread on the implant (lag-screw). there are variations on this, such as when the abutment and implant body are one piece or when a stock (prefabricated) abutment is used. custom abutments can be made by hand, as a cast metal piece or custom milled from metal or zirconia, all of which have similar success rates.: 1233 the platform between the implant and the abutment can be flat (buttress) or conical fit. in conical fit abutments, the collar of the abutment sits inside the implant which allows a stronger junction between implant and abutment and a better seal against bacteria into the implant body. to improve the gingival seal around the abutment collar, a narrowed collar on the abutment is used, referred to as platform switching. the combination of conical fits and platform switching gives marginally better long term periodontal conditions compared to flat-top abutments. regardless of the abutment material or technique, an impression of the abutment is then taken and a crown secured to the abutment with dental cement. another variation on abutment/crown model is when the crown and abutment are one piece and the lag-screw traverses both to secure the one-piece structure to the internal thread on the implant. there does not appear to be any benefit, in terms of success, for cement versus screw-retained prosthetics, although the latter is believed to be easier to maintain (and change when the prosthetic fractures) and the former offers high esthetic performance.: 1233 prosthetic procedures for removable dentures overdenturesfour lower implants to retain a complete denture with novaloc abutmentsunderside of a denture; housing fits like a ball and socket to hold the denturexray of four straumann implants and abutments when a removable denture is worn, retainers to hold the denture in place can be either custom made or "off-the-shelf" (stock) abutments. when custom retainers are used, four or more implant fixtures are placed and an impression of the implants is taken and a dental lab creates a custom metal bar with attachments to hold the denture in place. significant retention can be created with multiple attachments and the use of semi-precision attachments (such as a small diameter pin that pushes through the denture and into the bar) which allows for little or no movement in the denture, but it remains removable.: 33–34 however, the same four implants angled in such a way to distribute occlusal forces may be able to safely hold a fixed denture in place with comparable costs and number of procedures giving the denture wearer a fixed solution. alternatively, stock abutments are used to retain dentures using a male-adapter attached to the implant and a female adapter in the denture. two common types of adapters are the ball-and-socket style retainer and the button-style adapter. these types of stock abutments allow movement of the denture, but enough retention to improve the quality of life for denture wearers, compared to conventional dentures. regardless of the type of adapter, the female portion of the adapter that is housed in the denture will require periodic replacement, however the number and adapter type does not seem to affect patient satisfaction with the prosthetic for various removable alternatives. maintenance after placement, implants need to be cleaned (similar to natural teeth) with a periodontal scaler to remove any plaque. because of the more precarious blood supply to the gingiva, care should be taken with dental floss. implants will lose bone at a rate similar to natural teeth in the mouth (e.g. if someone has periodontal disease, an implant can be affected by a similar disorder) but will otherwise last. the porcelain on crowns should be expected to discolour, fracture or require repair approximately every ten years, although there is significant variation in the service life of dental crowns based on the position in the mouth, the forces being applied from opposing teeth and the restoration material. where implants are used to retain a complete denture, depending on the type of attachment, connections need to be changed or refreshed every one to two years.: 76 an oral irrigator may also be useful for cleaning around implants. the same kinds of techniques used for cleaning teeth are recommended for maintaining hygiene around implants, and can be manually or professionally administered. examples of this would be using soft toothbrushes or nylon coated interproximal brushes. the one implication during professional treatment is that metal instruments may cause damage to the metallic surface of the implant or abutment, which can lead to bacterial colonisation. so, to avoid this, there are specially designed instruments made with hard plastic or rubber. additionally rinsing (twice daily) with antimicrobial mouthwashes has been shown to be beneficial. there is no evidence that one type of antimicrobial is better than the other. peri-implantitis is a condition that may occur with implants due to bacteria, plaque, or design and it is on the rise. this disease begins as a reversible condition called peri-implant mucositis but can progress to peri-implantitis if left untreated, which can lead to implant failure. people are encouraged to discuss oral hygiene and maintenance of implants with their dentists. there are different interventions if peri-implantitis occurs, such as mechanical debridement, antimicrobial irrigation, and antibiotics. there can also be surgery such as open-flap debridement to remove bacteria, assess/smooth implant surface, or decontaminate implant surface. there is not enough evidence to know which intervention is best in the case of peri-implantitis. risks and complications during surgery placement of dental implants is a surgical procedure and carries the normal risks of surgery including infection, excessive bleeding and necrosis of the flap of tissue around the implant. nearby anatomic structures, such as the inferior alveolar nerve, the maxillary sinus and blood vessels, can also be injured when the osteotomy is created or the implant placed. even when the lining of the maxillary sinus is perforated by an implant, long term sinusitis is rare. an inability to place the implant in bone to provide stability of the implant (referred to as primary stability of the implant) increases the risk of failure to osseointegration.: 68 implant complicationsbone loss (peri-implantitis) on implants over 7 years in a heavy smokerrecession of the gingiva leads to exposure of the metal abutment under a dental crown.black triangles caused by bone loss between implants and natural teethfracture of an implant and abutment screw is a catastrophic failure and the fixture cannot be salvaged.fracture of an abutment (all-zirconia) requires replacement of the abutment and crown.fracture of abutment screws (arrow) in 3 implants required removal of the remainder of the screw and replacement.dental cement under the gingiva causes peri-implantitis and implant failure. primary implant stability primary implant stability refers to the stability of a dental implant immediately after implantation. the stability of the titanium screw implant in the patient's bone tissue post surgery may be non-invasively assessed using resonance frequency analysis. sufficient initial stability may allow immediate loading with prosthetic reconstruction, though early loading poses a higher risk of implant failure than conventional loading. the relevance of primary implant stability decreases gradually with regrowth of bone tissue around the implant in the first weeks after surgery, leading to secondary stability. secondary stability is different from the initial stabilization, because it results from the ongoing process of bone regrowth into the implant (osseointegration). when this healing process is complete, the initial mechanical stability becomes biological stability. primary stability is critical to implantation success until bone regrowth maximizes mechanical and biological support of the implant. regrowth usually occurs during the 3–4 weeks after implantation. insufficient primary stability, or high initial implant mobility, can lead to failure. immediate post-operative risks infection (pre-op antibiotics reduce the risk of implant failure by 33 percent but do not affect the risk of infection). excessive bleeding: 68 flap breakdown (less-than 5 percent): 68 failure to integrate an implant is tested between 8 and 24 weeks to determine if it is integrated. there is significant variation in the criteria used to determine implant success, the most commonly cited criteria at the implant level are the absence of pain, mobility, infection, gingival bleeding, radiographic lucency or peri-implant bone loss greater than 1.5 mm. dental implant success is related to operator skill, quality and quantity of the bone available at the site, and the patient's oral hygiene, but the most important factor is primary implant stability. while there is significant variation in the rate that implants fail to integrate (due to individual risk factors), the approximate values are 1 to 6 percent: 68 integration failure is rare, particularly if a dentist's or oral surgeon's instructions are followed closely by the patient. immediate loading implants may have a higher rate of failure, potentially due to being loaded immediately after trauma or extraction, but the difference with proper care