5

Patient Management and Surgery Preparation

A surgical procedure usually means extraordinary physical stress and anxiety as well as lost working hours and time for the patient. The result of a procedure performed intraorally cannot be 100% predicted due to the contaminated surgical field and cannot be guaranteed by the physician. The principle of participatory decision making ensures that patients recognize the necessity and the benefit for themselves and take joint responsibility for the result.

5.1 Elective Surgery

A dental implant procedure is usually elective. This means that, in contrast to vital indications, the patient and the doctor are free to choose the scope, procedure, timing, materials, and surgical environment to suit them. For both, this also means minimizing or avoiding unnecessary risks. Elective surgery offers the opportunity to carefully weigh and discuss the advantages and disadvantages in advance. The patient and the surgeon are free to choose the date. The procedure can be prepared in terms of materials, assistance, methods, etc. An implant procedure can be scheduled in reserved practice times, during which the team can concentrate on it without interruption. This calmness in the team is then also transferred to the patient and is a quality feature of the surgery performed.

5.2 Patient Selection According to Risk Factors

Preparation for an elective procedure also includes risk management based on the patient’s preexisting conditions. For example, in the case of an elective procedure, there is time to have high blood pressure checked again by the patient’s general practitioner before the procedure. If risk factors are present, referral to specialized centers is an option for difficult implant procedures.

Today, there are few real contraindications to augmentation surgery. The following should be mentioned here: simultaneous cytostatic treatments as part of tumor therapies as well as antiresorptive therapy such as the use of bisphosphonates or denosumab, an antibody against receptor activator of nuclear factor kappa-beta ligand (RANKL).

The former contraindications have largely become risk factors. This means that, if the case is severe enough and necessary, limited augmentation of soft tissue or bone can be indicated with the acceptance of an increased complication rate on both sides. There are hardly any risk calculations for complications associated with bone or soft tissue augmentations, only for dental implant placement, and here also only for early loss of dental implants. As an example of such risk calculations, a meta-analysis on implants placed in the irradiated jaw found a risk ratio of 2.18 for implant loss in the irradiated versus the healthy jaw.¹ In this study, the risk of implant loss was 4.6% in the healthy jaw group and 4.6% x 2.18 = 10.1% in the irradiated jaws. Approximately every tenth implant was lost in the irradiated jaw according to this meta-analysis, and one can use this handy figure in the patient education discussion. Further complications such as osteoradionecrosis must of course be taken into account in the indications and information (Fig 5-1). In the case of implant placement, however, attention should still be paid to the further risk-increasing combination of individual risk factors.

Fig 5-1 Wound-healing disorder after implant restoration with exposed bone in the mandible after radiation therapy.

In addition, the risk for wound-healing disorders is higher when bone and soft tissue augmentations are performed along with dental implant placement compared with dental implant placement alone. In this group of procedures, if risk factors are present, the indications should be particularly critical. In the case of all risk factors, the degree of suffering and the severity of the indication for the procedure must always be weighed on a patient-by-patient basis. For example, in the case of an unstable mandibular full denture, the severity is usually higher than in the case of replacement of an anterior tooth, which might also be possible with an adhesive bridge. The benefit must always be weighed against the risk of damage and an alternative selected if necessary. Primum non nocere, ie, first do no harm, is a basic rule in surgery.

Risk factors for augmentation surgery include poorly controlled diabetes mellitus with a glycohemoglobin fraction (HbA1c) greater than 7.5%. Smoking is a risk factor for early survival of dental implants depending on the amount of cigarettes and increases very strongly with more than 20 cigarettes per day.² For dental implant placement in combination with sinus floor augmentation in heavy smokers, the implant loss rate even increases to five times that of nonsmokers.³ A history of periodontitis increases risk for early implant loss,⁴ but this is negated for patients who have undergone periodontal rehabilitation and are receiving supportive periodontal therapy.⁵ Autoimmune diseases such as rheumatoid arthritis are risk factors mainly due to immunosuppressive medication. Especially with the immunosuppressive drug methotrexate, which is a cytostatic drug by folic acid antagonism, severe wound healing disorders are seen. Glucocorticoids are detrimental to wound healing, but one study showed no effect on early implant loss rate.⁶ Prostaglandins have a positive effect on bone healing, so antagonization by nonsteroidal anti-inflammatory drugs (NSAIDs) is always suspected of causing bone-healing disorders. However, there is a lack of studies on implantology and augmentation surgery.⁷ Newly coming into focus are proton pump inhibitors for the reduction of gastric acid and selective serotonin uptake inhibitors (antidepressants), which, based on the evidence level of retrospective studies, triggered an increased rate of early implant loss.^8,9 Vitamin D deficiency is common in the population, and a negative influence on the osseointegration of dental implants is suspected but could not be proven in studies so far.¹⁰ Malnutrition or undernutrition leads to wound-healing disorders¹¹; however, an age higher than 65 years does not increase the risk of implant loss.¹²

Fig 5-2 a. Hematoma in the floor of the mouth with respiratory obstruction due to swollen and elevated tongue after placement of a central mandibular dental implant in a patient without anticoagulant medication. b. Panoramic radiograph of the same patient. Such hematomas occur due to injury of oral floor arteries, especially during implant placement in the interforaminal region of the mandible with accidental lingual bone perforation.

Congenital or acquired coagulopathies represent a special risk group for augmentation surgery (Figs 5-2 and 5-3). The latter can be classified as thrombocytic (eg, acetylsalicylic acid [ASA] medication), plasmatic (eg, phenprocoumon therapy), or vascular (eg, Osler disease). As a rule, thrombocytic disorders are characterized by a prolonged intraoperative bleeding time, whereas plasmatic disorders are prone to extensive hemorrhage and hematoma even days later because no stable fibrin polymer (coagulum) is formed. Phenprocoumon and ASA are both characterized by long effect duration after discontinuation, so that short-term discontinuation of therapy does not provide any advantage for the frequency of re-bleeding. As a result, the strategy here is usually to reduce the invasiveness of the procedure and provide precise topical surgical hemostasis. New direct oral anticoagulants can be well controlled when taken orally; eg, after a waiting period of 12 hours after discontinuation of dabigatran, no increased bleeding complications occurred compared to the normal group.¹³ However, the possible discontinuation of anticoagulants should be discussed with primary care physicians and depends on the severity of the underlying disease. Implant placement alone is less critical than when combined with bone and soft tissue augmentations with regard to the risk of postoperative bleeding.

Fig 5-3 Facial hematomas with an ultimately mild course after implant surgery in a patient under anticoagulation treatment with phenprocoumon.

See Table 5-1 for a summary of the relative risk for dental implant loss associated with various medical and dental preexisting conditions.

Table 5-1 Relative risk (risk ratio) corresponding to the increased clinical risk for dental implant loss due to certain general medical and dental preexisting conditions compared with patients without this risk factor, calculated from meta-analyses and study data. Such data are not available for augmentation surgeries.

Implants and augmentations in osteoporosis

Osteopenia and osteoporosis can be prevented if one succeeds in developing peak bone mass early in life and in delaying the inevitable age-related decrease in bone mass thereafter as long as possible, so that one does not fall below the critical limit of fracture risk (Figs 5-4 and 5-5). According to a metaanalysis there was no significantly increased implant loss rate for patients with osteoporosis in almost 30,000 dental implants analyzed, only an increased marginal bone loss of 0.18 mm compared to patients with healthy bone mass.¹⁴ Dental implants are therefore possible in patients with osteoporosis. Nevertheless, osteoporosis should not be underestimated, because bone may have already lost 70% of its mineral content and stability before changes become visible as a warning sign on a conventional radiograph. As a result, drilling resistance when placing the implants can be unexpectedly low, and it is very difficult to achieve primary stability (Fig 5-6). In patients with osteoporosis there is a special indication for augmentation, with the aim of achieving firmer bone or a mechanically more favorable implant distribution, for example, by sinus elevation.

Fig 5-4 Representation of osteopenia and osteoporosis as an age-related deviation from the statistical normal distribution of bone mass.

Fig 5-5 Paramedian fracture of the right mandible during implant treatment in a 75-year-old female patient with osteoporosis. Delayed secondary fracture healing with formation of a callus zone and bone distention (elephant foot) can be seen. The suspicion of osteoporosis arises from this panoramic in view of the relatively thin basal cortical bone of the mandible, which has moth-eaten appearance on the left side.

Fig 5-6 Bone hardness in the implant site, classified according to Misch’s drill feel (Carl Misch, DDS, 1947–2017, US). The bone hardness results mainly from the distribution of cancellous bone and compact bone, as can be seen in the cross sections of the jaws.

Implants and augmentation with use of antiresorptive medication

A meta-analysis found that among patients with osteoporosis, those taking bisphosphonates did not have increased implant loss rates compared to those not taking bisphosphonates.¹⁵ Thus, dental implants are in principle also possible under bisphosphonate medication and possibly also under denosumab. On the other hand, the cited meta-analysis listed seven studies in which the occurrence of jaw necrosis in connection with dental implant placement in patients on antiresorptive medication was reported. Jaw necrosis occurred in 71% of cases in the mandible, predominantly posteriorly. Identified triggers of jaw necrosis were Implant placement (15 times), implant removal (5 times), and the pure presence of a dental implant (41 times). Because of these severe side effects (Fig 5-7), the indication for dental implants should be made very strictly, weighing the individual risk-benefit profile. According to current data, bone augmentation should be avoided altogether. The most favorable approach is to carry out a preventive sanitation of the dentition, including augmentations and implant placements, before starting antiresorptive therapy, if the indication permits this in terms of time.

Fig 5-7 Exposed bone and implant in the course of implant placement in a patient taking antiresorptive medication.

5.3 Informing the Patient

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