The Dental Implant Maintenance

As dental implant treatment has become a part of mainstream dental therapy, it is imperative to implement dental implant maintenance guidelines to achieve the long-term success of implant prostheses. Earlier, the success of a dental implant was mainly focused on the surgical phase to achieve good primary stability, with time, this belief has taken a major paradigm shift towards implementing and ensuring a periodic recall and following a maintenance phase for dental implants to achieve long-term success. As the dental team strives to attain and maintain the long-term success of implant prostheses, the patient should also recognize that their contribution towards the success of implant prostheses is also equally indispensable. This chapter highlights the importance of maintaining oral hygiene in implant rehabilitated patients and enumerates the implant maintenance protocol to be followed along with the different in-home and in-office procedures which can be implemented to achieve long-term success of the implant and peri-implant structures.


Introduction
The dental implant market value globally is expected to increase at a Compound Annual Growth Rate (CAGR) of 11% from 2021 to 2028 [1].This increase in demand for dental implant market size could be attributed to the numerous applications of implants along with the patient acceptance for implant prostheses.Despite the multitude of advancements made in surgical and technical fields of implant dentistry, the complications faced are still too high [2].In an observational study that was conducted to evaluate the patient's perception towards implant treatment and maintenance, it was concluded that most people were made aware of the importance of implant oral hygiene measurements and recall, however, the knowledge about implant-related complications and failures was dissatisfying.Although the patients were instructed about the importance of maintaining oral hygiene around implants, only 40.4% had reported having tried cleaning tools for maintenance [3].
We must acknowledge that implant placement requires a multidisciplinary treatment approach wherein a Maxillofacial surgeon, Prosthodontist, Periodontist, Oral Radiologist, Dental Hygienist, and the patient must work as a team to achieve long-term implant success.Hence, patients are considered as co-therapists in maintaining and achieving long-term implant success [4].
As the ideology of long-term implant success has taken a paradigm shift from attaining primary stability to implementing and ensuring periodic recall and maintenance, it is the responsibility of the dental team to convey the importance of oral hygiene maintenance and regular recall visits to the patients which can help them achieve long-term maintenance health of implant and the peri-implant structures.
Although there is scarce information available in the literature about dental implant maintenance protocols, in this chapter, we intend to compile in toto a detailed description of the various parameters which need to be examined and the measures to be implemented for achieving long-term implant success.

Risk factors that contribute to implant failures
The success of a dental implant depends primarily on the level of marginal bone loss, absence of mucosal inflammation, and probing depth.Risk factors that undermine the above criteria for long-term implant success should be explained to the patient and a comprehensive treatment plan must be presented to them.This comprehensive treatment plan must include all recommended dental therapy, possible alternative treatment options, the clinical risk which can be faced during the surgery, and the cost of the treatment.This discussion between the practitioner and the patient will help the patient understand why and how the procedure will be carried out.
Patient-specific risk assessment should include an extensive examination of the candidate and detailed medical and dental history.This will help the practitioner weigh the pre-operative and post-operative risks with implant placement.It is ideal and recommended to classify the implant patients according to their medical condition and associated co-morbidities using the American Society of Anesthesiologists Physical Status Classification System (ASA PS Classification) and co-relate their ASA PS status with the Type of dental treatment (Table 1) and their associated risk type (Table 2).

Sr. no Dental treatment Procedures
1.

Phase 1: assessment phase
The dentist will assess the patient's medical condition, analyze the risk factor/s which may pose as an etiology for the implant failure (Table 3).Along with the medical condition, the dental history of the patient should also be evaluated as it may provide us with information about the patient's oral hygiene and peri-implant status.It has been documented in multiple studies [37][38][39] that edentulous patients with high plaque scores before implant placement had experienced more implant failures than those with lower plaque scores.Furthermore, it has also been proven that patients treated for their periodontal conditions are more likely to experience implant complications compared to non-periodontal treated patients [40][41][42].Hence, to achieve long-term implant survival and success, patients with a previous history of aggressive periodontitis must undergo Supportive Periodontal Therapy (SPT) and diligently follow the regular maintenance phase and recall visits.
A typical maintenance phase should last for 1 h and should be scheduled every 3 months.The following are the parameters that are evaluated during the assessment phase of the implant maintenance protocol.

Peri-implant diagnostic parameters
The diagnostic parameters used to evaluate and monitor oral implants during the maintenance phase should have high specificity and sensitivity.We shall discuss the various peri-implant diagnostic parameters with modified dental indices that will be used during the assessment phase.

Plaque and mucosal assessment
Mombelli et al. [43] and Apse et al. [44] modified the plaque and mucosal assessment indices for peri-implant marginal mucosa and plaque evaluation (Table 4).

Peri-implant bleeding on probing
Similar to natural teeth conditions, the absence of bleeding on probing around peri-implant mucosa suggests a healthy implant soft tissue.In a study conducted by Lang et al. [45], it was concluded that healthy peri-implant sites were characterized by absence of bleeding on probing i.e. 0% whereas peri-implant mucositis reported 67% and peri-implantitis reported 91% of bleeding on probing.To avoid false-positive readings for bleeding on probing, Gerber et al. have recommended a minimum pressure of 0.15 N to be applied during the examination [46].

Peri-implant probing depth
Probing is an important and realistic diagnostic indicator for monitoring the peri-implant tissues.The probing force required is around 0.2-0.3N [47] and should always be measured using a periodontal probe from the mid-aspect of the mesiobuccal, buccal, distobuccal, mesiolingual, lingual, and distolingual surfaces of the implant.Probing depth for an implant having a supraosseous platform with healthy mucosa is around 2-4 mm [48].If the implant had been placed infrosseoulsy the probing depth may be slightly higher.However, an increase in clinical probing depth associated with bleeding on probing should be viewed as signs of peri-implant disease.

Peri-implant sulcus fluid analysis (PISF)
PISF has a substantial amount of biochemical mediators which act as a non -invasive host marker for identifying underlying peri-implant diseases.There have been studies conducted which show a positive correlation with PISF and plaque accumulation [55], degree of peri-implant soft tissue inflammation [55], and also the amount of bone resorption [56].

Suppuration
Suppuration is a confirmatory indicator of the disease activity and hence immediate anti-infective therapy is recommended [57].

Evaluation of food impaction around implants
Food impaction is one of the most common risk factors for developing periimplant diseases [58].Food impaction around implants can cause bleeding, edema, inflammation, halitosis, bone loss, pocket formation, implant mobility, and finally implant failure.The following is a classification for food impaction given by Chopra et al. [59] which will help us diagnose the cause for food impaction.
Class I: Food impaction present between either an implant supporting crown/ fixed dental prosthesis (FDP) and the adjacent natural tooth.
Class II: Food impaction present between either an implant supporting a single crown/FDP and a tooth with caries/faulty restoration/crown/FPD.
Class III: Food impaction present between two adjacent implants with either a single crown/FDP.
Class IV: Food impaction below the pontic of an implant with FDP.Class V: Food impaction around implant-supported/retained dentures.Class I-Class V has additional sub-categories based on the etiology of food lodgement [59].

Evaluation of implant mobility
Test for implant mobility is a primary factor for identifying the longevity of implant health.Implant mobility can be tested either by the conventional method or by using automated devices.The conventional method uses two rigid instruments that apply a labiolingual force of 500 g around the implant fixture to test its rigidity.The automated devices currently in use are Periotest and a non-invasive device that works on the principles based on Resonance Frequency Analysis (RFA).
The amplitude of implant mobility can be assessed using the Implant mobility scale given by Misch [60] (Table 5).

Occlusal evaluation
Occlusal evaluation must be done at regular intervals.Any deflective or premature contacts that may cause loosening or fracture of abutment screws, implant, or prosthetic failure must be evaluated and corrected.Parafunctional habits if present must be documented and treated accordingly as they may cause rapid bone loss [47].

Crestal bone loss and radiographic evaluation
Loss of crestal bone is a significant indicator of any ongoing peri-implant disease.After the prosthesis delivery, crestal bone loss around implants can be a primary indicator  e.In difficult to access regions especially the posterior area, end tufted brushes or tapered rotary brushes can be used.
b. Along with the mesial and distal surfaces, the facial and lingual surfaces should also be cleaned using the looping technique for effective debridement.
c. Patient should be instructed to place the floss subgingivally until resistance is met.
d. Dental floss can also be used to deliver antiseptic agents to the implants on daily basis.

Interproximal cleansers:
Foam tips, interproximal brushes, disposable wooden picks a. Chosen based on the size of the interproximal area.
b. Caution to be excised in cases where the interproximal brush has an exposed metal tip which can damage the peri-implant soft tissue and also the abutment's surface.
c. Chemotherapeutic agents can be delivered to the implant surface using the proxy and foam tip interdental brushes.

Water irrigation:
Hydro floss, Oracura a. Water stream should be directed interproximally and horizontally between implants or can cause damage to the peri-implant tissue Chemotherapeutic agents [65] Povidone iodine, Chlorhexidine gluconate, lasers, photodynamic therapy, or plant alkaloids a. Can be used in patients who have recurrent tissue inflammation in the form of rinses, gels, lozenges.
b.However, chlorhexidine gluconate has been proven to alter the surface topography of implants, and cause cell cytotoxicity thereby affecting the reosseointegration potential of implants [66] Table 6.
At-home oral implant hygiene care aids.
A preventive maintenance appointment should be scheduled every 3 to 4 months and a periapical/ bitewing radiograph should be made every 6 to 8 months.The periapical/ bitewing radiograph must be compared with the baseline radiographs to evaluate the crestal bone changes that have/have not occurred in the early stages of loading.
After 1 year, the previous radiographs must be compared with the recent bitewing radiograph and evaluated for further bone loss.If no changes are observed, a radiographic examination must be scheduled every 3 years, however, if there are noticeable unfavorable changes or crestal bone loss present, a radiographic evaluation must be carried out every 6-8 months along with stress reduction and hygiene maintenance protocol [60].

Phase 2: hygiene phase
Following the systematic assessment phase arduously performed by the clinician, it is now the responsibility of the patient, a co-therapist, to meticulously and habitually follow the implant oral hygiene protocol instructed by the clinician.After the implant
a. Metallic instruments should be avoided as they can scratch, contaminate or produce galvanic reactions at the implant-abutment interface.
b.If the prostheses limit the access to manual scalers, sonic or ultrasonic scalers with plastic or graphite-reinforced nylon tips may be used.
c. Depending on the sites of deposits, either horizontal, oblique, or vertical short working strokes with light pressure should be used to prevent inadvertent damage to the peri-implant tissues.
Polishing [65] Non-abrasive polishing pastes like aluminum oxide, tin oxide, APF free prophy paste, and low abrasive dentifrice a. Coarse abrasive polishing pastes and air polishing of implant components are contraindicated.
b. Air polishing may cause chipping of the porcelain or composite material.
c. May result in unwanted pitting or surface irregularities on the implant components and cause detachment of soft tissue from the implant surface due to air pressure.
a. Plastic irrigation tip may be used to introduce the antiseptic agents to the base of the implant sulcus.
b. Neutral sodium fluoride may be used instead of other fluorides which may have an acidic pH and thereby alter the implant surface Intraoral camera [65] a. Can be used to educate the patient about the effect of their oral hygiene care.
b. Based on the outcome of their previous oral care, any changes required can be implemented.This will help the patients to self-analyze their regular oral hygiene methods and motivate them to make necessary changes or continue with the same.

Table 7.
In-office oral implant hygiene care aids.
The Dental Implant Maintenance DOI: http://dx.doi.org/10.5772/intechopen.101187placement, patients usually have improper oral hygiene practice either due to the fear of damaging the implant or because of overzealous oral health care practice.Hence, as clinicians, it is important to convey both verbally and visually the different oral health care aids that can be practiced safely by the patients to achieve long-term implant success.
The following are the agendas to be covered in the hygiene phase: Directing the patient to control the underlying medical conditions which may cause peri-implant diseases and gradually implant failure.
Educating the patient about the importance of maintaining implant oral health and recall visits.
Training the patient to use different In-home hygiene products for the maintenance of implant oral health.
Oral implant hygiene methods can be broadly categorized as At-home implant care (Table 6) and In-office implant care (Table 7).

The implant health scale
The success of an implant should not focus on the implant fixture alone but also on the success of the entire implant prosthesis.A natural tooth in the oral cavity is not described as a success or failure, instead, a health scale is used to determine the condition and survival of the tooth.
Similarly, the implant health scale was introduced by James and further modified by Misch in the year 1993 [67,68].The Internation Congress of Oral Implantologists (ICOI), in Italy Consensus Conference, Pisa, on 5th October 2007, further modified the James-Misch Implant scale and approved a health scale with four categories for endosteal implants that describe their clinical conditions i.e. implant success, implant survival (satisfactory and compromised), and implant failure [69] (Table 8).After the final implant assessment phase, the clinician should categorize the implant health based on the assessed clinical condition of the implants.

Conclusion
The immediate outcome of implant dentistry for patients is usually esthetics and function.But long-term implant prosthesis success depends on an array of factors such as implant quality, implant surgery procedure, peri-implant health, implant/ prosthesis mobility, pain, exudate, etc.
A systematic review [70] was conducted to evaluate the different implant oral hygiene methods that are available and are in use by the general public and the dental team for the debridement of plaque and maintenance of implant oral health.It was concluded, that the knowledge that exists among the clinicians and the general public about oral hygiene maintenance is concerning natural teeth and no particular protocol or regimen were being followed [70].Hence, academics and private clinics must start spreading awareness both verbally and visually about the different implant oral hygiene aids which can be used to achieve long-term implant success.
The only elucidation to achieve long-term successful implant prosthesis is frequent maintenance recalls, regular professional and at-home implant hygiene care, as well as treating any peri-implant pathology at its earliest.In this chapter, we have meticulously compiled in toto the dental implant maintenance protocol and hope that the information provided will be helpful for the implant interdisciplinary team to guide the patient, educate them and simultaneously work with them to achieve long-term implant success.
mobility in any direction when 500 g force is applied 1Slight detectable horizontal movement with 500 g force 2 Visible moderate horizontal mobility up to 0.5 mm when a force of 500 g applied 3 Severe horizontal movement of more than 0.5 mm is seen when a force of 500 g applied 4 Moderate to severe horizontal movement along with any visible vertical movement

Table 2 .
Inter-relationship between ASA PS classification, type of dental treatment, and risk of implant placement.

Sr. no Systemic risk factors Influence on implant placement Contra-indication References
b. Due to reduced platelet count can result in uncontrollable hemorrhage in the surgical site.c.Can result in portal hypertension due to hepatic fibrosis during the surgery Relative [7, 19] The Dental Implant Maintenance DOI: http://dx.doi.org/10.5772/intechopen.101187Sr.

Table 3 .
Lists the different systemic conditions that can pose as a risk factor for implant placement.

Table 5 .
[64][62][63]lant mobility scale.The Dental Implant Maintenance DOI: http://dx.doi.org/10.5772/intechopen.101187 of the need for initial preventive therapy.Marginal bone loss of 0 to 0.2 mm after the first year of function is common and acceptable[61][62][63].However, a bone loss of 0.5 to 1 mm after the abutment is connected and during the first few years of the prosthesis in function is an indicator of excessive stress at the crestal implant-bone interface[64].The dentist should evaluate and reduce the cause of stress at the implant-bone interface which could be due to deflective occlusal contacts, cantilever length, or parafunction.