Static‐Computer Assisted Implant Surgery: Where Are We Now?

ABSTRACT

Background

Static Computer‐Assisted Implant Surgery (s‐CAIS) has become a widely accepted standard in guided implant placement, leveraging advancements in digital technologies. Despite its widespread adoption, s‐CAIS faces several limitations, and emerging alternatives like dynamic and robotic CAIS are gaining traction.

Methods

This narrative review synthesises the current literature on s‐CAIS to provide a comprehensive overview of its current state, clinical applications, and future potentials. Key aspects included s‐CAIS terminology and componentry, indications, clinical outcomes, patient‐reported experience, educational implications, advantages, and limitations.

Results

s‐CAIS demonstrates superior accuracy compared to non‐guided surgery. It can enhance efficiency in complex cases and facilitate minimally invasive and immediate loading protocols. However, limitations include restricted intraoperative flexibility, higher costs, and challenges in cases with limited access or unusual anatomy.

Conclusion

Despite emerging technologies such as dynamic navigation and robotic assistance, s‐CAIS remains a predictable and widely used modality for guided implant placement. Clinicians should weigh its advantages against limitations and consider patient‐specific factors when selecting guided surgery approaches. Further research should prioritise collective assessment of clinical and patient‐reported outcomes over accuracy metrics alone.

Summary.

• s‐CAIS is at present an affordable, accessible and predictable technology to assist accurate implant placement.

• Rather than a single technology, s‐CAIS is an entire workflow encompassing multiple steps and several interconnected devices.

• s‐CAIS can benefit the patients by increasing efficiency and reducing the invasiveness of implant procedures.

• Understanding not only the workflow but also its indications, potentials and limitations is imperative in modern implant practice.

• While advancements with dynamic and robotic CAIS may decrease the overall reliance on surgical guides, it is anticipated that s‐CAIS will continue to serve as the primary modality of guided implant placement in the near future.

1. Introduction

Prosthetically driven implant planning, combined with precise execution of Computer Assisted Implant Surgery (CAIS), has become the gold standard in dental implant rehabilitation [1]. Clinical evidence indicates that the factors of implant malposition [2, 3] and suboptimal prosthesis design [4] significantly compromise peri‐implant health and long‐term success. With the advent of digital innovations, prosthetic components can now be virtually designed according to established biological and mechanical principles. Consequently, achieving optimal clinical outcomes relies critically on the accurate translation of virtual planning into surgical reality.

Since the inception of computer‐aided planning and surgery in the late 90s [5, 6], static‐CAIS (s‐CAIS) has morphed into a predictable, clinically accessible and well‐documented surgical modality with over more than two decades of application. Numerous studies have reported their potential for enhancing the accuracy of implant placement [7], although certain limitations or challenges persist.

Meanwhile, new technological paradigms such as dynamic CAIS (d‐CAIS) and robotic CAIS (r‐CAIS) are rapidly emerging. These modalities offer enhanced intraoperative visualisation and surgical flexibility, yet they demand higher technical proficiency and come with increased costs. As the field continues to evolve, clinicians are faced with a critical decision point regarding the most appropriate CAIS modality for routine practice. Hence, a comprehensive overview of s‐CAIS is essential to support clinical decision‐making and promote evidence‐based practice.

The aim of this narrative review is to summarise the current state of the science and art in s‐CAIS and to clarify its role in contemporary clinical practice by focusing on the following aspects: (a) terminology and componentry, (b) indications, (c) clinical outcomes, (d) patient‐reported outcomes, (e) implications for education and training, (f) advantages and limitations, and (g) future directions and potentials.

1.1. S‐CAIS Terminology and Componentry

In the context of implant dentistry, a surgical guide is defined by the Glossary of Computer‐Assisted Implant Surgery and Related Terms [1] as “CAD/CAM device aiming to guide the osteotomy and the placement of a dental implant in the planned position or be used to guide other modifications of the anatomy, such as ostectomy, gingivectomy, sinus surgery, etc. This device is used temporarily in the patient's oral cavity during surgery with or without fixation elements.” Although surgical guide has historically been historically the focus of attention, the s‐CAIS workflow extends beyond surgical guides and requires a wider purpose‐made set‐up (Table 1), described as a Guided Implant Surgery System (GISS), which includes a variety of components to be utilised under an often‐proprietary Guided Implant Surgery Protocol (GISP). Key to the entire workflow is the digital treatment plan, which requires a sound understanding of implant dentistry and a specifically designed Computer‐Aided Design Implant Planning software (CAD‐IPS) [1].

TABLE 1.

Different elements of an s‐CAIS workflow, including characteristics of the surgical guide.

Aspect of s‐CAIS	Details
Extent of guidance	Fully guided Partially guided (including pilot drill guide)
Drill bit design	Sleeve‐in‐sleeve Mounted sleeve‐on‐drill Integrated sleeve‐on‐drill
Sleeves	Material	Stainless steel Titanium Zirconia PEEK
	Design	Open Closed
	Features	Self‐locking Non‐locking
Surgical guide	Support	Teeth‐supported Mucosa‐supported Bone‐supported Implant‐supported Hybrid
	Extent	Full coverage Partial coverage
	Stabilisation/retention	Fixation pins Ball clasps
	Multiple‐guides	Stackable guides Interchangeable guides
	Material	Acrylic Resin Metal (Stainless steel/titanium)
	Manufacturing	Additive (3D printing) Subtractive (Milling)
CAD Implant Planning Software (CAD‐IPS)	Access	Open platform Closed system
	Most documented brands	CoDiagnostix Nobel Clinician Bluesky Bio DTX Implant Studio Exocad Romexis 3D StendCad 6D Planning Simplant 3Diagnosys R2Gate OnDemand 3D RealGuide SMOP SmilePlan Galimplant Implant Viewer

Although most commercially available GISS abide by the same fundamental principles for guiding the osteotomy and implant placement, there is a wide variety of surgical guide and instrument designs, as well as corresponding protocols. It is important to note that this diversity in hardware, software, and protocols is rather attributed to different design philosophies among manufacturers, rather than comparative research [8]. Currently available GISS can be categorised in many ways, depending on the components and workflow in focus. From the point of clinical relevance, it might be most interesting to focus on the different (a) Surgical guide designs and (b) Guided implant surgery kits (GISK).

1.1.1. Surgical Guide Designs

Surgical guides have historically been used in many ways, from guiding only the pilot drill (pilot‐guided) to guiding the entire osteotomy (partially‐guided) and guiding both osteotomy and implant placement (fully‐guided). The fully guided approach has been shown to offer superior outcomes in terms of accuracy [9, 10, 11, 12, 13, 14, 15, 16]. Although it is well anticipated that all major design elements can contribute to clinical outcomes or predispose to complications and deviation, there is very little evidence comparing different surgical guide design elements and principles. Surgical guides can be organised based on the support mechanism:

• –Tooth‐supported (Figure 1a);
• –Mucosa‐supported (Figure 1b);
• –Bone‐supported (Figure 1c);
• –Implant‐supported
• –Hybrid (a combination of the above)

FIGURE 1.

(a–e) Different types of surgical guides organised on the basis of support.

Tooth‐ and mucosa‐supported surgical guides allow flapless or minimally invasive flap elevation procedures, whereas bone‐supported guides typically require full‐thickness flap elevation. Anchor or fixation pins can be used to ensure retention and stability, often arranged in a tripod configuration on the buccal or palatal, or a combination of both surfaces. In more complex cases where multiple guides are needed, the system may be stackable (Figure 1d) or interchangeable (Figure 1e). Stackable guides typically involve a base guide that is secured to the bone with fixation or anchor pins, upon which subsequent guides are placed using mechanical interlocking, pins, or magnets. Interchangeable guides rely on an initial guide to establish pin channels; once these are placed, the initial guide is removed and replaced with a subsequent guide that fits securely into the pre‐established pin positions.

Osteotomy surgical guides commonly incorporate sleeves to enhance drill guidance. The sleeves are inserted into the guide and stabilised either by friction fit or bonding. Regardless of the stabilisation method, it is essential to ensure that the sleeve remains secure throughout the surgical procedures (Figure 2). Sleeveless guides are also frequently used; however, some manufacturers have raised concerns about the potential generation of guide material debris contaminating the osteotomy site, caused by friction between the drill bit and the guide. The position of the sleeve should have sufficient clearance from the soft tissue or bone, and this is taken into consideration during the planning stage based on the CBCT and intraoral scan. The guide sleeve is available in various standard diameters and can be made of different materials, commonly titanium, steel, or Polyetheretherketone (PEEK), the latter of which could have locking or non‐locking features.

FIGURE 2.

Example of incomplete seating of sleeve in surgical guide being used to guide implant osteotomy.

A unique design feature for a tooth‐supported surgical guide is the incorporation of inspection windows, which allow clinical verification of full seating of the guide. It is recommended that these windows are positioned bilaterally to the implant site for optimal visual confirmation [17].

The surgical guide can then be additionally described based on the material it is made of, typically resin or acrylic and metal.

Surgical guides are not to be confused with intraoperative prosthetic templates (Figure 3), which are vacuum‐formed stents manufactured on a replacement tooth digital or analogue wax‐up to provide the proposed position of the final prosthesis as a reference to the surgeon. The continued use of such templates is based on operator preference; however, they do not, however, belong to the guided‐CAIS workflow.

FIGURE 3.

Examples of intraoperative template (non‐guided‐CAIS): (a) Mucosa‐supported partially guided stent. (b) Example of tooth‐supported pilot‐guided surgical stent.

1.1.2. Guided Implant Surgery Kits (GISK)

These kits consist of proprietary‐designed instruments such as drill bits, which interact with the surgical guide through a variety of interfaces. These instruments are essential for controlling the three‐dimensional position of the osteotomy. Common drill‐guide interfaces include sleeve‐in‐sleeve (with an additional handheld drill key or handle), integrated sleeve‐on‐drill designs, and mounted sleeve‐on‐drill systems with or without a sleeve in the surgical guide (Figure 4) [8].

FIGURE 4.

Designs of drills for different Guided Implant Surgery Systems (GISS) (Figure courtesy of Atiphan Pimkhaokham): (a) Sleeve‐in‐sleeve, non‐interlocking, (b) sleeve‐in‐sleeve, interlocking, (c) mounted sleeve‐on‐drill, (d) integrated sleeve‐on‐drill, (e) integrated sleeve‐on‐drill, sleeveless surgical guide.

Clinicians often report the sleeve‐in‐sleeve design as the most ergonomically challenging. It requires the surgeon to hold an additional component during the osteotomy, unless a self‐locking sleeve is used. These systems are typically developed by implant manufacturers to support implant placement of their specific production line. Assessment of GISK should consider not only accuracy, but also ergonomics and cost‐effectiveness, to provide clinically relevant insights and support informed decision‐making. Too often, the guide system is selected as a by‐product of implant choice, potentially limiting the clinicians' autonomy and efficiency.

1.2. Indications

Although surgical guides were initially developed for the accurate placement of dental implants, the concept gradually expanded to include other indications, either related to implant surgery (e.g., pre‐implant mandibular ostectomy) or non‐implant‐related procedures (e.g., crown lengthening surgery). Currently, the most common indications for the use of surgical guides as adjuncts to implant surgery include (a) bone reduction/ostectomy, (b) window osteotomy for lateral maxillary sinus floor elevation (MSFE), (c) immediate implant placement with the partial extraction/socket shield technique, and (d) zygomatic and pterygoid implant placement.

1.2.1. Bone Reduction/Ostectomy

Surgical guide can be designed to guide the amount of bone reduction to the planned level of implant platform (Figure 5). This is applicable in immediate implant cases with uneven bone levels around teeth with poor prognosis, or in fully edentulous patients presented with knife‐shaped alveolar ridge (Cawood and Hawell class IV) [18]. Currently there is little evidence with regard to the accuracy of bone reduction and its significance in relation to the final implant positioning [19]. Only one study with a small sample size of 4 patients reported a mean discrepancy in volume, level and angular deviation between virtual ostectomy and actual ostectomy of 493 mm³, 0.0248 mm and 6.03° respectively [20].

FIGURE 5.

Bone reduction guide (photo courtesy of Dr. Jarungvit Lorwicheanrung).

1.2.2. Lateral Maxillary Sinus Floor Elevation (MSFE)

In guided MSFE (Figure 6), the use of a surgical stent to transfer the outlines of the planned lateral window osteotomy can improve accuracy, reduce the time required, and possibly contribute to a reduction of morbidity by avoiding anatomical landmarks such as septa and vessels [21, 22, 23]. However, a recent clinical trial showed that patients operated on with s‐CAIS surgical guides in MSFE reported significantly more swelling than those who underwent free‐hand surgery. This prompted the authors to reflect and emphasise on the importance of guide design and to recommend the reduction of the size of the upper part of the frame, which corresponds to the superior border of the lateral window [23]. The surgical guide could also be designed to accommodate a hydraulic pressure device for the crestal sinus lift approach as part of the implant drill sequence (e.g., Crestal Approach Sinus/CAS kit).

FIGURE 6.

(a–c): Sinus lift surgical guide, (a, b) physical guide, (c) digital plan (photos courtesy of Dr. Peiman Yazdani).

1.2.3. Partial Extraction/Socket Shield Technique

The socket shield technique, which aims to preserve the labial bone in immediate implant cases, is a highly technique‐sensitive protocol requiring training and skills. Several case reports have described the use of a surgical guide to guide root separation prior to guided implant placement [24, 25]. However, no further comparative data are available on clinical outcomes of guided root shield preparation technique versus freehand.

1.2.4. Zygomatic/Pterygoid Implants

Zygomatic and pterygoid implants are considered viable alternatives for the rehabilitation of the severely atrophic maxilla, offering the advantage of avoiding extensive bone grafting procedures, reducing patient morbidity, and shortening overall treatment time. However, their placement is technically demanding due to the long drilling trajectory and the proximity of critical anatomical structures such as the orbital floor and the infratemporal fossa. Compared to s‐CAIS in conventional dental implantology, the application of surgical guides for zygomatic implant placement has been reported far less frequently in the literature [26, 27, 28, 29, 30, 31, 32]. Chrcanovic et al. noted that conventional surgical templates were insufficient for achieving accurate zygomatic implant placement [29], largely due to the challenges posed by the extra‐long implant length, which led to instability of the drill at the apical endpoint. An additional difficulty is in achieving proper stabilisation of the surgical guide on a severely resorbed, edentulous maxilla.

To address these limitations, modified s‐CAIS systems for zygomatic implant placement such as incorporating double sleeve designs and reinforced materials at the entry point and zygomatic emergence zone, have been suggested to improve accuracy [28, 33, 34, 35, 36]. A recent systematic review concluded that the use of double‐sleeve guide in zygomatic implant surgery produces clinically acceptable outcomes in terms of mean deviations [37]. Nevertheless, despite reporting favourable means, substantial maximum deviations were also reported. Thus, clinicians must remain vigilant for potential inaccuracies and complications, regardless of the guiding modality employed.

1.3. Clinical Outcomes

1.3.1. Accuracy (Trueness and Precision)

The accuracy of implant placement is the most extensively investigated parameter in s‐CAIS, serving as the central focus of a substantial body of both clinical and preclinical research aimed at validating its reliability [7].

Accuracy is typically quantified as the deviation between the planned and actual three‐dimensional (3D) implant position, specifically at the platform, apex, and angulation [38]. Historically, the term “accuracy” has often been used interchangeably with “trueness”. However, as directed by the latest directive of the International Standardisation Organisation (ISO 5725) [39], both trueness (the closeness of agreement between the planned implant position and the achieved implant position) and precision (the closeness of agreement between repeated implant placement under the same conditions) would be required to define accuracy. Thus, the majority of published clinical and simulation research should be interpreted as assessment of trueness alone. Little is known with regard to precision as only a few studies truly assessed and reported on precision [40, 41, 42, 43] in simulation studies.

A large body of clinical studies, also analysed collectively at several meta‐analyses [44, 45, 46, 47], has confirmed beyond doubt the ability of s‐CAIS to deliver superior trueness of implant placement than non‐guided surgery. At least with regards to the average deviation, the outcomes of s‐CAIS are comparable to what is achieved using d‐CAIS. A recent meta‐analysis [48] employed K‐means clustering to analyse the deviation outcomes from comparative clinical trials evaluating guided versus non‐guided implant placement. The analysis identified three primary clusters based on deviation patterns:

• Low deviation (< 0.67 mm platform, < 2.2° angle), which was the outcome of robotic or hybrid CAIS,

• Medium Deviation (0.67–1.30 mm platform, 2.2°–5.1° angle) which was dominated by implants placed under s‐ or d‐CAIS, and

• High Deviation (> 1.30 mm platform, > 5.1° angle) which was the outcome of non‐guided controls.

Thus, based on the current literature, the best available benchmark for s‐CAIS trueness is the range presented in the medium deviation group. However, accuracy metrics presented as stand‐alone numerical values often lack clinical interpretability, as they obscure critical spatial patterns essential for troubleshooting and workflow optimisation. For example, some authors have documented systemic deviation towards a specific direction (e.g., mesial‐distal or buccal‐lingual) or a clustering effect when implants were placed using a surgical guide [49, 50, 51], which they attributed to the influence of systemic errors in planning or execution such as habitual operator factors or ergonomics, surgical site access, guide misalignment, and the built‐in tolerance of the GISS. These directional trends are “invisible” in analyses focused on average trueness but reveal important limitations of s‐CAIS technology, especially under real‐life clinical conditions. Furthermore, when the deviation was analysed as a distribution curve [52], it was shown that implants placed with d‐CAIS appear to be more frequently within a favourable deviation margin (angular and apical) than those placed with s‐CAIS. Finally, although individual studies have failed to show any difference, meta‐analysed large data have favoured d‐ over s‐CAIS with regard to the achieved angular deviation [53, 54, 55, 56].

It must be noted as well that s‐CAIS is not a singular technology, but rather a multifaceted workflow comprising multiple sequential steps and the integration of various software and hardware components. Each element within this workflow has the potential to influence the final clinical outcome. Several steps and devices of this workflow have been assessed for potential contribution to the final trueness (Figure 7; Tables 2 and 3).

FIGURE 7.

CAD‐CAM surgical guide standardised, step‐by‐step protocol.

TABLE 2.

Major steps of the digital workflow in s‐CAIS with potential risk to introduce errors, which could cumulatively contribute to the clinical outcomes, in particular adding up to deviation from the planned implant position.

Stage	Potential risk for errors/inaccuracies
CBCT	Scattering induced by metallic restorations Movement artefacts Low sensitivity in detecting thin bone
Optical Scan (Intraoral)	Intraoral conditions Lighting conditions Scanner displacement Operator experience Inability to capture Mobile soft tissue
Optical Scan (Extraoral)	Analogue model distortion of the impression being replicated in the model scan
Digital Implant Treatment Plan (DITP) and Implant Planning Software (CAD‐IPS)	Selection of CAD‐IPS (surgical or restorative functionality) Data Registration accuracy Selection of proper planes Reduced Field of View or insufficient landmarks for data registration Accuracy of data segmentation, in particular when algorithms are used (Over‐segmentation/under‐segmentation) Panoramic curve simulation
Guide design	Path of insertion, attention to undercuts Optimal kind of tissue support selection Material selection Material thickness Anchorage elements design and location
Guide fabrication and storage	Printing/milling errors/discrepancies Deficient curing of resin Storage & transport conditions Dimensional changes or structural deformation Sleeve insertion, cementation and stability
Guide seating	Misfit/improper fit Deficient stability Inadequate tolerance (too tight/too loose) Interference with soft tissue thickness
Guide use (Intraoperative)	Displacement Fracture Inability to insert/withdraw guided drills Systemic error due to ergonomic access

TABLE 3.

Factors of surgical guide design and drill support which can influence the trueness of the final implant position (or other outcomes, if specifically mentioned) as suggested by simulation and clinical trials.

Factors	Accuracy (trueness) level	Study types
Surgical guide support	‐ Teeth or implant > Mucosa > Bone [10, 38, 44, 49, 57, 58, 59] ‐ Mucosa = Bone [60] ‐ More teeth ↑ higher trueness [61] ‐ Posterior > Anterior teeth [62] ‐ Two teeth on each side = Full‐arch surgical guide covering seven teeth [63] ‐ 6 teeth > 4 teeth (single immediate placement) [61]	[10, 44, 49, 58] a [57] b [38, 60] c [59] d [61, 62, 63] e
Guide design/material	Rigid > Flexible [14] Sufficient thickness [14]	[14] d
Guide fabrication method	Accuracy: Additive = Subtractive [64, 65, 66]; Milling > 3D printing [67, 68] Cost‐effectiveness: 3D printed > Milled [59] * 3D printers have different manufacturing accuracy [68, 69, 70]	[67] a [59] e [64, 65, 66, 68, 69, 70] d
Size of edentulous space	Single tooth gap > Extended edentulous span [57, 62]	[57] b [62] d
Location of the gap	Bounded saddle > Distal extension [13, 57, 63, 71, 72, 73] Anterior implant > Posterior [12]	[13, 73] a [57] b [12, 71, 72] e [63] d
Immediacy	Healed sites > Fresh extraction sockets [74]	[74] e
Flap	Flapless > Flap [15, 75, 76]	[15, 75, 76] a
Implant design	Deep‐threaded tapered > Shallow‐threaded parallel‐walled [77]	[77] d
Sleeve	Sleeveless > Metal sleeve (for sleeve‐in‐sleeve system) [77, 78, 79] Metal sleeve = Sleeveless (for mounted or integrated sleeve‐on‐drill systems) [42, 80] Sleeveless > Metal sleeve (for mounted sleeve‐on‐drill and sleeve‐in‐sleeve drill systems) [74, 81] Sleeveless > Metal sleeve (for mounted sleeve‐on‐drill) [82]	[81] a [82] c [42, 74, 77, 78, 79, 80] d
Sleeve design	Closed sleeve > Open sleeve design > Freehand (in healed sites and immediacy cases) [83, 84]	[83] e [84] d
Sleeve height	Higher sleeve > shorter sleeve [85, 86, 87]	[85, 86, 87] d
Drill key design	Keyless > Sleeve‐in‐sleeve [74, 88] Sleeve‐in‐Sleeve > Keyless [80, 85]	[88] a [74, 80, 85] d
Drill key length	Longer drill key > Short drill key [87, 89]	[87, 89] e
Drill length	Short drills > Long drills [17, 62, 87]	[17] b [62, 87] d
Guide offset	Minimum essential guide‐to‐teeth offset: 0.1–0.15 mm [62, 77, 79, 90] Minimal bone offset or sleeve‐to‐bone distance ↑ higher accuracy [40, 62, 78, 86] Minimal sleeve‐to‐guide and drill‐to‐sleeve offset/tolerance ↑ stability [86, 87]	[40, 62, 77, 78, 79, 86, 87, 90] d
Guidance	Fully guided > Partially guided > Pilot guided [9, 10, 40, 46, 76]	[9, 10, 46, 76] a [40] e
Other elements	Fixation pins ↑ stability in mucosa‐ and bone‐supported guides [16, 91] and in edentulous cases [67, 92, 93] More fixation pins ↑ higher trueness [49] Cross‐arch support bar > No bar (↑rigidity, distortion [94, 95, 96] and ↑stability [97]) One‐piece guide > Stackable guide (↓cumulative errors) [19]	[49, 67] a [19] b [16, 92, 93, 94, 95] e [91, 96, 97] d

Note: “>” indicating superior outcome, “ = ” indicates comparable outcome, “↑” indicates positive association, “↓” indicates negative association.

^a Systematic review (in vivo, ex vivo, in vitro).

^b Critical review/scoping review.

^c Randomised Clinical Trial.

^d Simulation study.

^e Clinical Trial.

1.3.2. Time Efficiency and Cost‐Effectiveness

S‐CAIS has been shown to significantly reduce chairside time during complex interventions such as multiple implant placement in fully edentulous patients, particularly when performed using a flapless surgical technique [59, 98]. In partially edentulous patients, the evidence regarding surgical time remains inconsistent. While some studies have reported shorter surgical time with fully guided and pilot guided s‐CAIS compared to non‐guided placement [99, 100], others have demonstrated similar results between the approaches [101, 102]. However, in cases of single gap, non‐guided CAIS or conventional surgery appears consistently faster, especially in simple, straightforward cases [8, 103, 104]. Seating and removal of surgical guide may prolong the duration of the surgery, particularly when intraoperative adjustments are needed to enhance guide fit. Although such modifications are generally infrequent, reported adjustment times vary considerably, ranging 1–17 min [23].

1.3.3. Teeth‐In‐a‐Day (Immediate Loading)

It is not surprising that immediate loading was the indication that introduced the concept of guided implant placement as early as 1999 [6], as accurate placement of the implants is essential to allow immediate restoration with prefabricated prostheses (Figure 8). The time required to fit the temporary prosthesis was found to be significantly shorter when surgical guides were used [99], while patient satisfaction with the overall treatment is shown to be more influenced by the presence of immediate restoration than by the extent of post‐operative discomfort [99, 105], particularly in the aesthetic zone, where patients' expectations are higher.

FIGURE 8.

Immediate pick up for full‐arch restoration. Immediate fixed prosthesis enables better control of loading forces and directions on the implants and provides cross‐arch stabilisation for the implants. (Photo courtesy of Dr. Peiman Yazdani).

1.4. Patient Reported Outcomes

Few studies have investigated patient‐reported outcomes (PRO) and patient‐reported experience (PRE) with the use of s‐CAIS [106, 107]. A randomised study by Amorfini et al. showed that patients expressed significantly higher confidence in s‐CAIS compared to the non‐guided group prior to the surgery, although both groups reported similar overall satisfaction afterwards [99]. A retrospective study by Youk et al. showed that s‐CAIS patients reported less discomfort, reduced emotional distress, and higher satisfaction compared to free‐hand surgery but brought up the issue of financial burden associated with the cost of CAIS [108].

Studies including both flap and flapless implant surgeries have found no statistically significant difference in intraoperative pain between patients operated on with s‐CAIS and those undergoing the free‐hand procedure [109, 110, 111]. However, when flapless surgery was combined with s‐CAIS, patients reported lower intra‐operative and post‐operative pain levels and consumed less post‐operative analgesic compared to conventional, open flap approaches [59, 75, 112, 113, 114]. Furthermore, higher patient satisfaction with overall treatment outcomes appears to be associated more with the presence of immediate restoration [99, 105], especially in the aesthetic zone.

1.5. Education and Training

Clinicians need to undergo specific training to effectively apply the s‐CAIS workflow in practice, which extends from the data collection to digital treatment planning and execution of guided implant surgery including troubleshooting and quality assurance of all stages. The actual execution of surgery using a surgical guide does not appear to be a highly demanding task, often depicted with a learning curve of increasing returns [115], suggesting that clinicians can reach the accuracy “plateau” after relatively little training and time on task. s‐CAIS has the potential to narrow the performance gap in implant placement accuracy between experienced and novice surgeons. A number of small sample studies found no difference in the accuracy with s‐CAIS regardless of the experience level of the surgeon, while some showed higher deviation in inexperienced surgeons in the coronal, bucco‐lingual direction and implant angulation [116, 117, 118]. Nevertheless, even if s‐CAIS can help inexperienced operators reach higher accuracy [111], it should not be perceived as compensation for the lack of experience or spatial representation ability [119] but rather as the means to increase reproducibility and efficiency of a procedure the surgeon is fully competent to design and perform freehand if needed [120]. In addition, as s‐CAIS limits the tactile proprioception of the operator and the visualisation of anatomy, it is also reported to be an inferior learning experience for the novice practitioners compared to freehand surgery [121]. Therefore, s‐CAIS might provide greater clinical value at a more advanced stages of training, particularly after proficiency in freehand implant placement is established and procedural optimisation becomes the primary focus.

1.6. Advantages and Limitations

1.6.1. Advantages of s‐CAIS Over Non‐Guided

Compared to conventional techniques, s‐CAIS can significantly improve the trueness of implant placement and reduce the duration of complex surgeries, potentially contributing to increased patient satisfaction. By enhancing accuracy and predictability, s‐CAIS could reduce surgical risks and morbidity in anatomically critical regions, such as nerves, vessels, maxillary sinus, and adjacent tooth roots. With a preceding meticulously crafted bio‐restorative digital treatment plan, guided placement could empower immediacy protocols with prefabricated prosthesis, facilitate the use of minimally invasive protocols (e.g., flapless approach) [59, 101, 106, 112, 113, 114], as well as avoid short‐and long‐term complications [122].

1.6.2. Advantages of s‐CAIS Over d‐CAIS

Currently, the primary comparative advantages of s‐CAIS over d‐CAIS include a significantly smaller initial investment, simpler device componentry, and the relatively easier training and mastery. S‐CAIS is widely adopted and available at a lower cost for patients. Having a surgical guide in place expedites the determination of the entry point of the pilot drill and subsequent drills and increases implant platform accuracy compared to d‐CAIS [46]. The combination of s‐ and d‐CAIS techniques may help to ease the learning curve process for dynamic navigation while the operator achieves the level of hand‐eye‐screen coordination required.

1.6.3. Limitations

S‐CAIS comes with an array of contraindications and limitations. The use of s‐CAIS is contraindicated in cases with restricted mouth opening, patients with excessive gag reflex, or limited interocclusal space, where the insertion of the surgical guide with the drill and handpiece simultaneously might be challenging or impossible. Further limitations might include the application in narrow gaps (< 5 mm, typical diameter of sleeve) or where an unusually long implant has been planned (14 mm or more). The surgical guide may also restrict the access of irrigation to the osteotomy site [123, 124, 125] (Figure 9). Using drills with internal irrigation, incorporating a buccal opening near the sleeve, or employing a separate irrigation syringe with the tip positioned between the guide and the bone may help deliver irrigation better to the osteotomy site.

FIGURE 9.

Mucosa‐supported surgical guide retained by pins—note how a well‐fitted drill in the metal sleeve prevents irrigation from the handpiece from reaching the other side of the stent.

Furthermore, there is no real‐time visualisation of the implant trajectory or surgical site. Likewise, the operator's tactile sensitivity and proprioception of the bone quality may decrease, which might conceal bony defects such as dehiscence, low bone density, or reduced primary stability [7]. In addition, intraoperative adjustments of the implant position or angle are not possible unless the surgical guide is abandoned [126]. Reportedly, implants placed with static surgical guides tend to be inserted 0.5–1.5 mm shallower than planned, particularly when following the fully guided protocol. This could result in a wide emergence angle, impairing oral hygiene and affecting marginal bone levels [127].

Cost may also be a barrier for s‐CAIS uptake among clinicians and patients. S‐CAIS requires the use of implant planning software usually available with a licensing fee, intraoral or lab scanners, a guided surgery kit, and the cost of the surgical guide, all of which would be transferred to the patient and reflected in higher treatment costs.

Most importantly, the benefits of s‐CAIS are only relevant if the planning of the implant surgery has been carried out correctly; otherwise, the accuracy and benefits afforded by s‐CAIS would be rendered meaningless.

1.7. Future Directions and Potentials

Although s‐CAIS has evolved significantly since its inception, its fundamental principles remain unchanged; progress has been driven mainly by incremental refinement of the componentry. The use of GISS and GISK has reached the level of an affordable, accessible, and predictable technology to assist accurate implant placement. At the same time, the absence of a qualitative breakthrough and the relative paucity of evolution and development in this field speaks of a technology that has reached its peak potential. Incremental improvements in accuracy or efficiency are still possible through the evolution of 3D printing technology and improvements in the printable materials; however, these developments are unlikely to produce transformative changes in the clinical performance of static guides.

The field of digital treatment plan is undergoing rapid transformation, with artificial intelligence‐powered software demonstrating significant potential to automate repetitive tasks such as 3D image segmentation and alignment while actively generating treatment plans and customised components. Importantly, these advancements are applicable to enhance all CAIS workflows, beyond static guidance. At the same time, the seamless execution of the digital treatment plan is hampered by the limited interoperability between different software and devices [120].

Manufacturers of digital services, software and devices should prioritise open and collaborative workflows which enable seamless integration of implant planning into broader treatment workflows; for example, by accommodating orthodontic tooth movement projections during implant space planning. Cross‐platform interoperability, elimination of proprietary barriers that currently fragment comprehensive treatment workflows and clinician ownership of the digital treatment plan will allow the true multi‐disciplinary approach, essential in complex cases.

Recent clinical trials [52, 128, 129, 130], including a network meta‐analysis [56], have demonstrated that a surgical guide, when combined with a navigation system, could further reduce implant position deviation as compared to the use of either technology alone. Still, it is doubtful if this combination would have indications in mainstream clinical practice, as this incremental increase in trueness comes at a significant cost in terms of time in preparation and on task, costs, and facilities. Furthermore, patient‐specific factors and clinical indications may exclude a higher proportion of cases from s‐CAIS suitability compared to the d‐CAIS alternative.

Following known paths of maturation of innovative technologies, navigation systems are bound to become more affordable, more compact, and expand their scope of indications. While these advancements may decrease the overall reliance on s‐CAIS, it is anticipated that s‐CAIS will continue to serve as the primary modality of guided implant placement in the foreseeable future.

2. Discussion

After development of 25 years since its initial inception, s‐CAIS has been established as a reliable and affordable workflow for placing dental implants with high accuracy. Its use can increase the efficacy and efficiency of dental implant therapy, facilitate treatment protocols of higher complexity, and improve treatment outcomes and patient experience. At the same time, it is currently difficult to envision significant improvements in the devices or protocols of s‐CAIS, which is suggestive of a technology that has reached its maturity.

Accuracy of implant placement has been the most studied outcome with regards to s‐CAIS, but also any other technology of guided implant surgery. Nevertheless, despite the plethora of research on accuracy, the actual threshold at which accuracy translates to substantial clinical benefits for the intended treatment remains unclear. Increasing accuracy is an important clinical parameter for the success of well‐planned interventions, as accurately placed implants as part of a bio‐restorative, prosthetically driven treatment plan have better marginal bone stability, aesthetics and long‐term prognosis with lower rates of biological and mechanical complications [122]. At the same time, the relentless drive towards zero deviation might be more of an academic pursuit, especially when the critical thresholds of accuracy essential for the desired clinical outcomes are largely unknown. Future studies in CAIS might need to divert focus from the accuracy achieved to the actual clinical outcomes [7], for example how frequently the use of s‐CAIS allows the seamless placement of prefabricated prosthesis or how frequently extensive modifications are required. Future research should also investigate education and training efficiency, as well as patient experience with the actual clinical outcomes that s‐CAIS can empower, rather than comparing isolated surgical procedures [107].

With multiple implant companies offering guided surgery systems featuring subtly different surgical kits, it can be confusing even for experienced clinicians to choose a system to adopt. Since the core workflow concept is consistent across systems, clinicians would benefit from structured training on the s‐CAIS workflow, including its potential and limitations. Experimenting with different GISS would then allow for a more informed selection and adaptation of the proper tools. While s‐CAIS could increase efficiency and shorten the duration of surgical intervention, the on‐screen time spent on digital implant treatment plan and guide design is often overlooked. This process requires training and could be time‐consuming; thus, it is often a deterrent for experienced clinicians who have been achieving consistently good results with non‐guided surgery. Mastering digital implant treatment planning requires different levels of effort for each clinician, influenced by their personal motivation and the intuitiveness of the software used. Artificial intelligence and algorithms based on machine learning are envisioned to undertake much of the digital treatment planning in the near future, automating the process and reducing the burden for the clinician. It is recommended to try out a few software solutions [131] before investing in one and incorporating it into the workflow. It is also crucial to choose an open platform to enable collaboration in cases involving a more complex workflow and to keep abreast of the latest developments in digital technologies in general. Outsourcing the task of digital treatment plan and guide design to a laboratory or a central production facility [131] might be a viable option, albeit with cost implications. Even so, the clinician maintains full responsibility for the plan and designs; thus, one should be at least competent to review the treatment plan and guide designs, confirm the level of quality, and adherence to biological principles and technical standards. Since patients ultimately bear these costs, the anticipated benefits must clearly justify them, and the parameter of cost‐effectiveness requires further investigation.

3. Conclusion

Despite its limitations, s‐CAIS has become the established standard for guided implant placement, serving as the benchmark for comparison for all other technologies. Although technologies and workflows such as d‐CAIS and r‐CAIS have shown promising results in terms of the accuracy of implant placement, each comes with its own challenges and limitations. Thus, s‐CAIS is anticipated to remain the dominant modality for guided implant placement in the foreseeable future, albeit with declining importance.

Conflicts of Interest

The authors declare no conflicts of interest.

Data Availability Statement

Data sharing not applicable to this article as no datasets were generated or analysed during the current study.