Zygoma plus

Key points

  • •

    Zygomatic implants offer high survival rates but are limited by procedural complexity, invasiveness, and potential complex sinus-related complications.

  • •

    Conventional placement may result in suboptimal prosthesis contours and hygiene challenges due to anatomic limitations and natural pattern of maxillary atrophy in the palatal direction.

  • •

    The Zygoma Plus protocol is a patient-centred approach with flexibility in the type of anchorage, implant number and use of bone grafting to control the outcome, improve contingency and reduce risks.

  • •

    Vertical slot, hockey stick, and sinus crush techniques allow precise, prosthetically guided zygomatic implant placement and adaptation to individual anatomy while ensuring optimal correlation to the prosthesis for comfort and hygiene.

  • •

    Minimally invasive zygomatic implants precision osteotomy technique facilitates safe sinus access, membrane preservation, optimal engagement within the zygomatic bone and optimal implant positioning.

  • •

    Immediate Final Teeth with a rigid frame using a digital workflow offer an additional level of control by reducing the bio-mechanical burden on individualimplants during healing.

Abbreviations

3D 3 Dimensional
CAD computer-aided design
CBCT cone beam computed tomography
CEP crestal entry point
CTV compound torque value
FMA Frankfort-Mandibular Plane Angle
PMMA polymethyl methacrylate (milled)
PRF platelet rich fibrin
VDO vertical dimension of occlusion
ZEP zygoma entry point
ZIPO zygomatic implants precision osteotomy

Introduction

The use of zygomatic implants has increased in recent years. Yet despite reported high survivals, zygomatic implants have been proposed and used with some reluctance due to the invasiveness and complexity of the procedure and potential intraoperative complications, as well as the known biological complications particularly those associated with the maxillary sinus.

In conventional graftless techniques, zygomatic implants are placed in a manner to preserve and optimize reliance on the residual alveolar ridge. However, the pattern of atrophy of the edentulous maxilla is in the palatal direction, , and in dentate patients, the sinuses may be pneumatized and surround the roots of the teeth. , The morphology of the maxilla may also change by the wearing of a denture resulting in extrusion of the posterior residual ridges (combination syndrome) , limiting the restorative space available for the upper prosthetic teeth to occupy at the correct occlusal plane. For these reasons, the anatomy of the residual alveolar bone, maxillary sinuses, and soft tissues rarely correlates to the most optimal position and contours of the proposed prosthetic teeth. Placement based entirely on anatomic considerations may lead to bulky restorations with uneven contours affecting patient’s enjoyment and cleanability and may, in turn, lead to biologic complications with significant morbidity due to the proximity to the sinus.

When reserving Zygomatic implants only for the most atrophic cases, the outcome is compounded by the anatomical complexity resulting in shifting the focus towards surgical containment of the implants within available bone, inevitably ignoring the restorative compromises, which are often a primary contributor to future surgical complications.

Accessibility for hygiene becomes even more critical as the use of zygomatic implants expands beyond the edentulous population, and to younger patients with terminal dentitions, who often lose their teeth due to lifestyle choices or a lack of motivation and cannot be further impaired by an iatrogenic barrier. To decrease the incidence of biological complications, zygomatic implants, like conventional implants, should be placed in a manner allowing a maxillary prosthesis to be fabricated with full access to the implants for maintenance.

Zygoma plus protocol

The Zygoma Plus protocol is a component of All On 4 Plus patient-centered system (System) for full arch fixed implant-based rehabilitation. Irrespective of the type of anchors, the use of 4 implants is preferred to reduce the biologic strain with less connections; thus, simplified cleaning, but more implants may at times be needed to reduce the mechanical strain depending on individual circumstances when there is an imbalance between the forces (imparted through function, diet, habits, or parafunction) and the resistance of the scheme, which depends on bone quality and bone quantity, and which can be improved with cortical engagement, the use of longer implants, more implants, and bone grafting.

The System has evolved since 2002 to predictably ensure

  • 1.

    Optimal surgical placement of implants for comfort and cleanability;

  • 2.

    Adequate anchorage for long-term bio stability (including by incorporating remote anchorage and zygomatic implants);

  • 3.

    Adequate restorative space for aesthetics and durability; and,

  • 4.

    A reliable immediate restoration to further help reduce the biomechanical burden.

Most notably, it has the needed flexibility on a minimalistic approach (eg, in relation to the type and number of implants or use of bone grafting) to manage all clinical and anatomic situations, and since 2006 includes the routine delivery of immediate final teeth fixed on 4 or more (or sometimes less) implants, enhancing the patient’s journey and experience, while at the same time also helping to better control the outcome by creating an environment, which is conducive to biostability over time and the patient’s enjoyment ( Figs. 1–3 ).

Fig. 1

Top view of immediate final teeth before insertion, showing a narrow prosthesis with a cleanable interface.

Fig. 2

Occlusal view of immediate final teeth in mouth after 12 months, showing healthy tissues and a thin restoration offering optimal comfort and cleanability.

Fig. 3

Conventional dental panoramic radiograph of Zygoma Plus treatment at 12 months with visible bone grafting along the trajectories of the right zygomatic implant and posterior left zygomatic implant.

The Zygoma Plus protocol involves techniques that enable accurate placement and adaptation of zygomatic implants according to the prosthetic needs, and making modifications to the anatomy using bone reduction and/or bone grafting (see Fig. 3 ) as required to achieve the most optimal restorative outcome.

Fig. 3 ; Figs 4–6 illustrate the same case involving Straumann ZAGA and BLX implants using various methods resulting in an ideal implant position as determined by the location of the access holes in the prosthesis in Fig. 4 – yet in Fig. 5 showing the healed tissues, it is not possible to ascertain the type of implant in each position without referring to the radiograph.

Fig. 4

Immediate final prosthesis (inserted within 24 hours) showing idealized implant positions.

Fig. 5

Clinical appearance of the soft tissues at 2 years.

Fig. 6

CBCT reconstruction of Zygoma Plus treatment at 2 years review. Quadrant 1 has Straumann ZAGA Flat and the bone graft is stable around the coronal part of the implant. Quadrant 2 shows 2 ZAGA Flat implants with the posterior of the 2 showing substantial stable bone graft along the entire shaft, whereas the anterior showing a much thinner layer along the shaft due to its mostly extra maxillary placement (requiring less grafting). The sinuses are clear on both sides.

The use of bone grafting is clearly visible as a lining along the zygomatic implants in the conventional panoramic radiograph at 12 months (see Fig. 3 ) as well as on the reconstructed CBCT radiograph taken at 24 months (see Fig. 6 ).

The incorporation of immediate final teeth (visible on the radiograph in Figs. 3 and 6 ) with its rigid titanium frame not only improves the patient’s treatment journey but also offers a critical layer of control and protection during healing, and especially when procedures are adopted that increase the biologic burden, such as when incorporating bone grafting along with the placement of zygomatic implants and in a way that focuses on the restorative outcome.

Zygoma plus antrostomy techniques

There are 3 techniques used in the Zygoma Plus protocol to attain prosthetically driven adaptation of zygomatic implants: vertical slot, hockey stick, and sinus crush.

The placement of the zygomatic implants using any of these techniques may be extramaxillary, partially-extramaxillary, or completely intramaxillary (within the sinus) depending on the anatomy of the maxilla and extent of pneumatization of the sinuses, but in almost all cases awareness and manipulation of the sinus tissues is required, whether or not bone grafting is also planned or used.

Vertical slot technique

Description and rationale

The slot technique is a minimally invasive antrostomy outlining only the shape and trajectory of the zygomatic implant ( Fig. 7 ) or part of the trajectory, which is in proximity to the sinus and/or the zygoma bone. As a minimally invasive technique, it is suitable in cases where the zygomatic implant would not substantially infringe into the sinus space after determining the coronal emergence and trajectory of the implant for an idealized prosthetic ( Fig. 8 ).

Fig. 7

Simplified diagrammatic illustration of the slot technique.

Fig. 8

Zygoma Plus vertical slot technique, minimally invasive osteotomy keeping the lateral wall of the sinus intact, partially extramaxillary placement.

The concept of a slot was used by Stella and colleagues in 2000 as a means to simplify position and orientation of zygomatic implants placement, but the sinus membrane was not preserved (unlike the Zygoma Plus protocol). It also resembles the ZAGA channel osteotomy but follows prosthetically guided placement rather than Zygomatic anatomy -guided approach as prescribed under the ZAGA protocol.

The slot facilitates exploration of the internal curvature of the zygoma bone to determine an appropriate entry point at the base of the zygomatic bone.

The technique preserves the sinus mucosa ( Fig. 9 ), involves a minimum amount of bone grafting as an additional buffer between the implant and the sinus ( Fig. 10 ), and allows for a close adaptation of the implant to the bony edges ( Fig. 11 ), which in certain cases offers additional stabilization of the implant, similar to the Stella slot except with the aforementioned bio-physiological benefits. The close adaptation of the implant to the walls of the slot acts as a barrier protecting the grafts and tissues medial to it. It reduces the biologic strain and facilitates osseointegration along the shaft of the implant. Overall, whilst there is a less volume of grafted bone for contingency, the thinner layer of the graft is able to heal and mature within a shorter timeframe, thus reducing biological risks over time.

Fig. 9

Slot preparation exposing Schneiderian membrane.

Fig. 10

The slot is lined with a graft material.

Fig. 11

Straumann ZAGA flat implant in position.

Implant placement and profile

As the slot technique is typically used when the maxillary anatomy is concave, the implant is typically positioned as partly extramaxillary or extramaxillary placement (see Fig. 11 ).

When the lateral aspect of the sinus is more convex or bulbous and the expected implant position is deeper within the sinus, then a hockey stick approach is preferred for improved visualization and access to avoid tearing the Schneiderian membrane.

Indications

  • •

    Lateral aspect of maxilla is concave (like labial aspect of ZAGA 2 or 4 when referenced to an idealized prosthetic ( Fig. 12 )

    Fig. 12

    Concave lateral maxillary wall.

  • •

    Lateral aspect of maxilla is flat/concave or convex, but the lateral wall of the sinus is thicker than 2 mm ( Fig. 13 ).

    Fig. 13

    Lateral sinus wall is thicker than 2 mm.

  • •

    Simple unhindered slot elevation along the entire planned trajectory. No sinus septa or roots that could result in sinus mucosal tears (unless this can be controlled).

Procedure

A slot in the bone on the lateral aspect of the maxillary sinus is created along the line of the implant trajectory toward the zygomatic bone until reaching the zygomatic bone thickening. The slot may be created in 1 of 2 ways:

Option 1

Once the prosthetically driven crestal entry point (CEP) for the zygomatic implant is determined, provided it does not breach the floor of the sinus (or the sinus mucosa has already been reflected and protected), the drilling sequence can use tip and side cutting drills to elegantly and precisely create the slot ( Fig. 14 ).

Fig. 14

Tip and side-cutting drill (Versah) is used to carve out the slot.

Option 2

Preparation using a 2-mm round bur is commenced at the base of the zygoma ( Fig. 15 ), and a FIBI-1 sinus elevator is used to isolate the sinus mucosa ( Fig. 16 ). Once there is a 7 to 10 mm long slot from the base of the zygomatic bone, the lower part of the slot can be prepared by using the 2-mm drill or a diamond side-cutting drill ( Fig. 17 ).

Fig. 15

2-mm round drill.

Fig. 16

FIBI-1 sinus elevator.

Fig. 17

ANDO side-cutting drill is used to remove the bone on the lateral and define the slot.

The side-cutting diamond drill may not be used in situations where the prosthetically driven CEP for the zygomatic implant is such that the crestal bone can be preserved with adequate coronal encasement to enable the use of a ZAGA Round coronally threaded implant, in which case option 1 is preferable.

Once the bone is removed along the slot exposing the membrane, the sinus lining is gently and minimally elevated along the slot and only slightly beyond avoiding overinstrumentation ( Fig. 18 ).

Fig. 18

FIBI-1 sinus elevator (long curved side).

Bone grafting is used in most cases but not always. When used, it is minimal as its only purpose is to protect the sinus mucosa during drilling (in areas where required, Figs. 19–25 ).

Fig. 19

Bio-Oss Collagen is used as a thin layer along the slot.

Fig. 20

NanoBone is layered over the Bio-Oss Collagen to create a water-repelling base for the drilling sequence.

Fig. 21

The osteotomy is performed according to the zygomatic implants precision osteotomy sequence.

Fig. 22

ZAGA profiler is used to optimize the adaptation of the implant collar to the crest.

Fig. 23

The slot lined with bone grafting ready for the implant.

Fig. 24

Straumann ZAGA Flat. The driver is attached to the mount screw to verify the angulation in relation to the lower.

Fig. 25

Platelet-rich fibrin (PRF) membranes are used on the buccal aspect before closure.

In cases where the maxilla is extremely concave and implant position is likely to be entirely or substantially extramaxillary, the slot may only be required at the base of the zygomatic bone to enable instrumentation to explore the internal anatomy of the zygoma. In those situations, grafting is not required because its protective function at that level is less important and not critical to the outcome ( Fig. 26 ).

Fig. 26

Radiograph showing anterior piriform and nasal floor cortical anchorage with Straumann BLX and zygoma slot with grafting in quadrant 1 and without grafting in quadrant 2 using ZAGA Flat (the case shown in see Figs. 16–26 ).

The concept of a sinus grafting using a minimally invasive slot in a horizontal direction has been shown to be a safe technique with low complications. The cross-sectional radiographs in Fig. 27 show the maturation of the graft after 2 years along the trajectory of the zygomatic implant.

Fig. 27

( A–F ) Cross section of the slot technique after 2 years showing clear sinuses and apposition of a thin layer of bone along the length of the implant. The sinus is clear.

Hockey stick antrostomy

Description and rationale

Hockey stick antrostomy resembles the shape of the bottom section of a hockey stick. Similar in concept and application to the Caldwell-Luc lateral sinus lift and trapdoor approach described by Tatum, ,, the shape and larger window improves visualization, instrumentation, and control of the sinus mucosa. This technique facilitates preservation and repair of the sinus mucosa, as well as exploration of the internal curvature of the sinus and zygoma bone to determine an appropriate entry point at the base of the zygomatic bone ( Figs. 28 and 29 ). Grafting is used to protect sinus membrane during drilling and improves contingency once mature.

Fig. 28

Illustration of the hockey stick technique.

Fig. 29

Straumann ZAGA Flat implant placed with hockey stick technique.

Implant placement and profile

Since the hockey stick technique is typically used when the lateral sinus wall is flat or convex, the implant is typically positioned intrasinus or partly extramaxillary . It may also be extramaxillary where isolating and protecting the sinus mucosa during instrumentation may not be a factor, but grafting is desired for future contingency.

Indications

The hockey stick technique is used under the following conditions:

  • •

    The lateral aspect of maxilla is flat or convex and the implant is anticipated to be largely within the sinus (like labial aspect of ZAGA 0 or 1 when referenced to an idealized prosthetic) ( Figs. 30 and 31 );

    Fig. 30

    Lateral window is extended with a slot superiorly toward the zygomatic bone along the proposed implant trajectory to create the shape of the bottom of a hockey stick.

    Fig. 31

    The depth gauge outlining the planned implant trajectory. The sinus is wide and hollow with flat or slightly convex buccal aspect resulting in the bulk of the body of the implant to be within the sinus. The anterior part of the hockey stick remains accessible for further control during the osteotomy and placement.

  • •

    The lateral wall of the sinus is thin (not thicker than 1.5–2 mm); and/or

  • •

    There are teeth roots encroaching the sinus space or septa requiring better access for more delicate instrumentation of the sinus, whether concave or convex; and/or

  • •

    More extensive sinus grafting is desired specifically for contingency.

Procedure

A lateral window is created on the lateral aspect of the maxillary sinus (like described by Tatum ) extending distally to the line of the planned implant trajectory ( Fig. 32 ).

Fig. 32

Round drill outlining the hockey stick antrostomy.

The stick portion of the hockey stick resembles the superior aspect of the slot technique, created by extending a slot from the distal-superior corner of the lateral window along the line of the implant trajectory laterosuperiorly toward the zygomatic bone until reaching the zygomatic bone thickening. The slot is created using the same 2-mm round drill used for the lateral window but can also be extended using the tip of a tip and side-cutting drill (as described earlier for the slot technique) once the sinus lining is isolated and protected.

The sinus floor is gently elevated ( Figs. 33 and 34 ) particularly surrounding the planned zygomatic implant entry point, which is a critical zone ZICZ, but also extending further anteriorly and distally (for an extended contingency graft, as desired). If the sinus mucosa is thin, a PRF membrane is layered over it before the application of a bone graft (as later described).

Fig. 33

FIBI-3 Sinus membrane elevator.

Fig. 34

FIBI-1 Sinus membrane elevator.

The window allows excellent visualization and improved accessibility for instrumentation at the floor of the sinus with the curved FIBI-3 sinus membrane elevator (see Figs. 33 and 34 ). The superior slot is accessed with the FIBI-1 sinus membrane elevator to determine the shape and thickness of the internal inferior surface of the zygomatic bone (see Fig. 34 ), and the zygomatic entry point (discussed later).

Compressed PRF membrane is then used to line the Schneiderian membrane ( Fig. 35 ), which is layered with Bio-Oss Collagen ( Fig. 36 ) and NanoBone ( Figs. 37 and 38 ) to create a protected and stable base for the implant osteotomy ( Figs. 39 and 40 ).

Fig. 35

Compressed PRF membrane lines the sinus membrane.

Fig. 36

Bio-Oss Collagen is layered over the PRF membrane.

Fig. 37

NanoBone is gently applied over the Bio-Oss.

Fig. 38

The NanoBone is gently pressed over the Bio-Oss to create a stable bed for the drilling sequence.

Fig. 39

The NanoBone helps protect the Bio-Oss and the sinus mucosa and does not dissolve or disperse, instead repels water.

Fig. 40

The osteotomy is completed without disturbing the graft or traumatizing the sinus tissues.

The rationale and detailed procedures for using these materials is covered later under bone grafting.

With the sinus tissues protected by the graft, the zygomatic implant can be safely positioned without risking entrapment of soft tissues or sinus contaminants in its path ( Figs. 41 and 42 ).

Fig. 41

Straumann ZAGA Flat implant can be accurately positioned due to improved visibility and protected sinus space.

Fig. 42

A 2.5-mm SRA is fitted, which is compatible with the platform of the other abutments in the arch.

Palatal-Keratinized soft tissues can be adapted over the reduced alveolar ridge to enhance the periimplant biotype ( Fig. 43 ) and PRF is placed on the buccal aspect ( Figs. 44 and 45 ).

Fig. 43

The excess palatal keratinized tissue as a result of the alveolectomy is adapted over the ridge and around the implant.

Fig. 44

Grafting is completed within contained defects but avoided over the buccal of the implant.

Fig. 45

PRF is applied.

Bone grafting is almost always applied with hockey stick technique ( Fig. 46 ), the only exception being if the sinus mucosa is extremely thin (or absent) or if there is an unrepairable perforation. The existence of roots, uneven internal morphology, or apical infections increase the risk for perforation, as well as the presence of arteries that also cause additional hindrance from bleeding if severed during the procedure.

Fig. 46

Radiography following zygoma placement using the hockey stick technique. More extensive bone grafting is visible surrounding the zygomatic implant.

In such cases, bone grafting does not take place and repair is achieved with soft tissues and PRF only. While this is less ideal and does not fulfill the contingency aims, the intraoperative decision must be balanced against the elevated risk for complications (or severity), otherwise associated with a perforation and uncontained bone grafting ( Figs. 47–50 ).

Fig. 47

Large perforation during hockey stick preparation.

Fig. 48

Two pin holes are made in the bone distal to the body of the implant and a thick layer of PRF is sutured to those pin holes lining the implant on the inside of the sinus.

Fig. 49

The PRF is sutured in place.

Fig. 50

PRF is applied on the buccal aspect before closure.

Sinus crush technique

Description and rationale

A sinus crush is a procedure where sinus elevation and soft bone graft material is used to facilitate an upward impaction (crush) alveoloplasty of the sinus floor to improve restorative space (when required and appropriate) when an alveolectomy is not feasible due to the pneumatization of the sinus within the alveolar ridge below the level of the needed vertical height reduction.

The outcome of this technique resembles a crestal window sinus lift described by Soardi and colleagues and osseodensified crestal window augmentation described by Salgar with an additional vertical adjustment for restorative space as required.

Implant placement and profile

Since the sinus crush technique involves a vertical upward repositioning of the sinus floor, the implants are typically intrasinus and with limited or absent crestal support ( Figs. 51 and 52 ), but they may also be partially extramaxillary depending on the lateral maxillary anatomy.

Fig. 51

Diagrammatic illustration of the sinus crush technique.

Fig. 52

Sinus crush illustrating the zygomatic implant suspended off the cheekbone without any crestal support.

Indication

When the required vertical bone reduction must necessarily extend beyond the inferior border of the sinus and into the sinus space.

Procedure

Sinus crush antrostomy typically begins from the lateral aspect as a hockey stick as this provides adequate access to carefully reflect the sinus lining. The approach may vary depending on access, shape of the sinus, and presence of septa or roots, and at its minimal form (depending on position for an idealized prosthesis), it may be in the form of a slot.

The sinus elevation necessarily extends to the palatal wall, and the mucosa is separated from the bone at the floor of the sinus. Once the sinus pocket is grafted and the lining protected, an upward impaction may be achieved with an alveolectomy or creation of a crestal window and removing the plate of bone at the floor of the sinus. The end result typically leaves an opening at the crest where the graft material is visible from the occlusal view, and there is no crestal support ( Fig. 53 ).

Fig. 53

The sinus is accessed using a hockey stick approach. The sinus membrane elevation must extend to the palatal wall, a crestal opening results after bone reduction for restorative space.

It is critical in sinus crush procedures to optimize engagement within the zygomatic bone with careful preparation of the bone using the zygomatic implants precision osteotomy method (discussed later). Whenever possible, some crestal support is advantageous, for example, with some mesial inclination of the trajectory allowing the implant collar to rest on the mesial aspect of the crestal window. An example of a sinus crush procedure incorporating a minimal mesial crestal rest is illustrated in the following sequence ( Figs. 54–68 ).

Fig. 54

Hockey stick approach and bone grafting using Bio-Oss collagen. A PRF membrane is often adapted to the sinus mucosa before the insertion of the graft.

Fig. 55

NanoBone is used to provide a stiffer base.

Fig. 56

Once the sinus is grafted and protected, the sinus crush may take place by cutting back the crestal bone through the sinus space to the required level. The graft is visible though the crestal opening.

Fig. 57

FIBI-3 sinus membrane elevator is used through the crestal opening to endure that the sinus mucosa is adequately reflected and not entrapped by the graft.

Fig. 58

NanoBone is added to provide a firmer base for drilling.

Fig. 59

The bone graft may be further lightly compressed through the crestal opening before the drilling.

Fig. 60

The osteotomy is performed according to the zygomatic implants precision osteotomy sequence (later discussed).

Fig. 61

The osteotomy is completed without disturbing the graft or traumatizing the sinus tissues.

Fig. 62

A depth gauge is used ensuring the implant length is adequate to penetrate the apical cortex. It is critical in sinus crush procedures for the zygomatic implant to penetrate the apical cortex for maximum engagement and stability due to the absence of a crestal rest.

Fig. 63

It was possible to have a crestal rest on the mesio-palatal aspect of the implant head, this is advantageous.

Fig. 64

Bio-Oss Collagen is layered to fill the mesial aspect of the lateral window, but not over the implant.

Fig. 65

Collagen membrane is used over the implant and grafted crestal opening.

Fig. 66

Preop smile showing excessive gum display on the right and supraeruption of the premolar, which required a larger alveolectomy and necessitating a sinus crush due to the low position of the sinus.

Fig. 67

The final result with immediate final teeth inserted within 24 hours from the surgery.

Fig. 68

Postoperative radiograph showing use of Zygomatic implants using sinus crush on the right (quadrant 1) piriform and midline implants for anterior support, as well as a Pterygoid implant on the right side due to the sinus crush procedure and a zygomatic implant otherwise unsupported at the crest.

Overall, sinus crush is a technique-sensitive procedure with the potential for more significant complications because the bone at the inferior border of the sinus (which provides a crestal rest to support the coronal portion of the zygomatic implant) is necessarily removed.

The inability to achieve a crestal rest for the implant in many (not all) sinus crush procedures adds a layer of complexity and biomechanical compromise. The concern without an adequate rest is a long-lever effect and microflexure of the implant due to:

  • 1.

    The elasticity of the zygoma bone itself, which depends on the quality of the bone and extent of cortical engagement within the zygomatic bone; and

  • 2.

    The elasticity of the implant itself, which depends on the diameter and length of the unanchored part of the implant ( Fig. 69 ).

    Fig. 69

    Anchorage within the zygomatic bone and flexure of the unsupported part of the implant proportional to its length.

Microflexure may interfere with the proper healing and adaptation of the implant in the early stages and in the medium to long-term may lead to recurring mucosal irritation due a micropump effect causing ingress of bacteria in the coronal part of the implant. As such, sinus crush procedures should be accompanied by careful case selection ensuring that the quality and quantity of the zygomatic bone is more than minimally adequate, and require additional mitigating measures including

  • •

    Reducing or avoiding a posterior cantilever ;

  • •

    Adding a Pterygoid implant in cases where the biomechanical burden is elevated;

  • •

    Use anticlenching injection before treatment and every 3 months in first year;

  • •

    Avoid pressurized hygiene devices like Water-Pik;

  • •

    Attainment of high individual implant stability of the other implants in the group with cortical anchorage where possible; and,

  • •

    Attainment of the requisite compound torque value

Primary stability and anchorage options

Individual implant torque and stability

Implant stability is a prerequisite for immediate loading and may also be a determinant of prognosis. , The highest possible torque up to 80 Ncm (but not under 35 Ncm) should be achieved for individual implants (Straumann BLX, TLX, BLC, and TLC), and up to 50 Ncm (but not under 35 Ncm) for zygomatic implants ( Fig. 70 ).

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Sep 27, 2026 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Zygoma plus

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