Digital Workflow for Implant Placement and Immediate Chairside Provisionalization of a Novel Implant System without Abutment—A Case Report

Dental implants have been placed millions of times worldwide, and the surgical procedure and implant design have steadily improved. The basic prosthetic connection, which makes use of an abutment, has changed little over the past decades. These days, implant placement with immediate provisionalization is an essential stage in implant dentistry and interdisciplinary treatment strategies. Temporary computer-aided design and computer-aided manufacturing (CAD/CAM) of implant-supported crowns restore esthetics and guarantee function during the restoration process and the osseointegration of the dental implant. This case report describes the digital planning; the immediate, static, computer-assisted implant surgery, and the immediate chairside provisionalization of a novel implant system that is directly screw-retained without an abutment.


Introduction
The CAD/CAM (computer-aided design/computer-aided manufacturing) systems used for decades in restorative dentistry have expanded their applications to implant dentistry. Today, these systems enrich the dental implant treatment with the diagnosis and planning as well as in the actual surgical and prosthetic procedures [1,2]. With continuous improvements in intraoral scanning technology, material innovations, and new software updates, this technique is becoming increasingly prevalent [3][4][5][6]. However, the implant interfaces have remained unchanged for the past decades. The innovation of the novel implant system (Matrix Implant, TRI Swiss Implants, Hünenberg, Switzerland) is the implant-prosthetic connection: due to CAM processing, no abutment is needed for the prosthetic construction, and the restoration is directly connected with the implant. Singleunit restorations with a corresponding implant-prosthetic connection can be milled in one piece from prefabricated temporary blocks or zirconiumoxide for definitive solutions. The bonding to a titanium base is, therefore, no longer necessary. According to the manufacturer, there is no limitation in angulation (up to 100 • between implants), and it allows for direct restorations from screw-retained, fully anatomic CAD/CAM crowns to multi-unit bars and bridges, which can be planned and placed directly on the implant. The digital planning enables a patient-specific, individual emergence profile. The pink anoidized neck optimizes translucency in the gingival tissue. The geometry of the interface in the shape of an open circle can be produced with any kind of suitable CAD/CAM material without the necessity of an opening of a prefabricated protection against rotation. In addition to the Tooth 14 had been extracted 4 years ago, and teeth 13 and 15 had already been prepared for an FDP. The patient did not accept the foreign body sensation of the temporary bridge pontic and requested implantological treatment ( Figure 1). Implant diameter platform 3.7 mm Implant diameter enossal 3.3 mm Implant length 11.5 mm Tooth 14 had been extracted 4 years ago, and teeth 13 and 15 had already been prepared for an FDP. The patient did not accept the foreign body sensation of the temporary bridge pontic and requested implantological treatment (Figure 1).
A radiological image of tooth 15 showed an insufficient root canal treatment with apical extrusion of the root canal filling and an apical translucency, PAI = 3. The patient was referred for endodontic revision treatment. Teeth 13 and 15 received new long-term temporaries (LTT) (Telio CAD, Ivoclar Vivadent, Schaan, Liechtenstein). The bone height was sufficient (measured on a CBCT scan). Suitable anatomical conditions (mesial-distal, buccal-palatal, and interocclusal space) to place an anatomically designed screw-retained restoration were present and complied with good oral hygiene practices. The patient had no medical and general contraindications for the surgical procedure and did not smoke or show severe bruxism with dysfunctional tendencies. The presence of acute untreated periodontitis in the implant bed or adjacent tissue could be excluded. Written informed consent was obtained from the patient before being enrolled for implant treatment. The patient underwent implant placement and chairside provisionalization according to the treatment procedures described in Table 2.  A radiological image of tooth 15 showed an insufficient root canal treatment with apical extrusion of the root canal filling and an apical translucency, PAI = 3. The patient was referred for endodontic revision treatment. Teeth 13 and 15 received new long-term temporaries (LTT) (Telio CAD, Ivoclar Vivadent, Schaan, Liechtenstein). The bone height was sufficient (measured on a CBCT scan). Suitable anatomical conditions (mesial-distal, buccal-palatal, and interocclusal space) to place an anatomically designed screw-retained restoration were present and complied with good oral hygiene practices. The patient had no medical and general contraindications for the surgical procedure and did not smoke or show severe bruxism with dysfunctional tendencies. The presence of acute untreated periodontitis in the implant bed or adjacent tissue could be excluded. Written informed consent was obtained from the patient before being enrolled for implant treatment. The patient underwent implant placement and chairside provisionalization according to the treatment procedures described in Table 2.

Diagnostic and Planning Procedures
Prior to the implant treatment, intraoral scans of the upper jaw, lower jaw, and a lateral bite registration (CEREC Primescan SW 5.2. Dentsply Sirona, Charlotte, USA) as well as a cone beam computed tomography (CBCT) scan were made ( Figure 2). sionalization Placement of the chai

Diagnostic and Planning Procedures
Prior to the implant treatment, intraoral scans of the uppe lateral bite registration (CEREC Primescan SW 5.2. Dentsply Sir well as a cone beam computed tomography (CBCT) scan were m The intraoral scans and CBCT Digital Imaging and Commun COM) file were superimposed with an implant planning software Dental Wings, Chemnitz, Germany) to create an individualized d

Diagnostic and Planning Procedures
Prior to the implant treatment, intraoral scans of the uppe lateral bite registration (CEREC Primescan SW 5.2. Dentsply Sir well as a cone beam computed tomography (CBCT) scan were m The intraoral scans and CBCT Digital Imaging and Commun COM) file were superimposed with an implant planning software Dental Wings, Chemnitz, Germany) to create an individualized d The prosthetically driven implant position was decided by de and the natural bone width in a palatal position with a ≥2 mm d plant and the buccal crest and a depth of 3-4 mm apical of the zenith point [32]. The implant length was chosen based on the a The prosthetically driven implant position was decided by determining the tooth axis and the natural bone width in a palatal position with a ≥2 mm distance between the implant and the buccal crest and a depth of 3-4 mm apical of the prospective restorative zenith point [32]. The implant length was chosen based on the available bone height. A pilot-drill surgical template to facilitate static, computer-assisted implant surgery was designed with the implant planning software and printed (SolFlex, W2P; Austria) ( Figure 4).

Surgical Procedures
The surgical procedure was performed using local anesthesia (Ultracain D-S Sanofi-Aventis Deutschland GmbH, Frankfurt am Main, Germany). A marginal inc with mesial and distal relief to expose the bone and prepare a minimal mucoperio flap was made in order to obtain an intraoperative overview and to assess the bone qu ( Figure 5). In order to gain proper primary stability, a pilot drill (Tri Swiss Implants, Hünen Switzerland) with the use of a surgical template was utilized ( Figure 6).

Surgical Procedures
The surgical procedure was performed using local anesthesia (Ultracain D-S forte, Sanofi-Aventis Deutschland GmbH, Frankfurt am Main, Germany). A marginal incision with mesial and distal relief to expose the bone and prepare a minimal mucoperiosteal flap was made in order to obtain an intraoperative overview and to assess the bone quality ( Figure 5).

Surgical Procedures
The surgical procedure was performed using local anesthesia (Ultracain D-S forte Sanofi-Aventis Deutschland GmbH, Frankfurt am Main, Germany). A marginal incisio with mesial and distal relief to expose the bone and prepare a minimal mucoperiostea flap was made in order to obtain an intraoperative overview and to assess the bone qualit ( Figure 5). In order to gain proper primary stability, a pilot drill (Tri Swiss Implants, Hünenberg Switzerland) with the use of a surgical template was utilized ( Figure 6). In order to gain proper primary stability, a pilot drill (Tri Swiss Implants, Hünenberg, Switzerland) with the use of a surgical template was utilized ( Figure 6).
A second drill (Tri Swiss Implants, Hünenberg, Switzerland) was used to prepare the coronal third of the alveolus. The neck area was prepared with a countersink drill. A tissue-level tapered implant (Matrix Tissue-Level Implant, TRI Swiss Implants, Hünenberg, Switzerland) with a Ø 3.3 mm enossal (Ø 3.7 mm platform) and a length of 11.5 mm was inserted according to the manufacturer's instructions (Figures 7-9). A second drill (Tri Swiss Implants, Hünenberg, Switzerland) was used to prepa coronal third of the alveolus. The neck area was prepared with a countersink drill. sue-level tapered implant (Matrix Tissue-Level Implant, TRI Swiss Implants, Hünen Switzerland) with a Ø 3.3 mm enossal (Ø 3.7 mm platform) and a length of 11.5 mm inserted according to the manufacturer's instructions (Figures 7-9).  (a) (b) Figure 6. (a) Surgical cassette TRI dental implants; (b) implant bed preparation with tape using a surgical template.
A second drill (Tri Swiss Implants, Hünenberg, Switzerland) was used to pr coronal third of the alveolus. The neck area was prepared with a countersink dr sue-level tapered implant (Matrix Tissue-Level Implant, TRI Swiss Implants, Hü Switzerland) with a Ø 3.3 mm enossal (Ø 3.7 mm platform) and a length of 11.5 inserted according to the manufacturer's instructions (Figures 7-9).  (a) (b) Figure 6. (a) Surgical cassette TRI dental implants; (b) implant bed preparation with tapere using a surgical template.
A second drill (Tri Swiss Implants, Hünenberg, Switzerland) was used to prep coronal third of the alveolus. The neck area was prepared with a countersink drill sue-level tapered implant (Matrix Tissue-Level Implant, TRI Swiss Implants, Hüne Switzerland) with a Ø 3.3 mm enossal (Ø 3.7 mm platform) and a length of 11.5 m inserted according to the manufacturer's instructions (Figures 7-9).  Primary implant stability was attained with a maximum insertion torque of 45 Ncm, verified with a manual torque controller to check if the implant stability was sufficient for immediate temporalization. The scanbody was screwed onto the implant and closed using sutures (5-0 polytetrafluoroethylene) to complete the treatment. The surgical procedures were performed by one oral and maxillofacial surgeon. Primary implant stability was attained with a maximum insertion torque of 45 Ncm, verified with a manual torque controller to check if the implant stability was sufficient for immediate temporalization. The scanbody was screwed onto the implant and closed using sutures (5-0 polytetrafluoroethylene) to complete the treatment. The surgical procedures were performed by one oral and maxillofacial surgeon.

Restorative Procedures
The implant situation was digitalized using a scanbody (TRI Swiss Implants, Hünenberg, Switzerland; Cerec Primescan, SW 5.2., Charlotte, USA) (Figures 10 and 11). Primary implant stability was attained with a maximum insertion torque of 45 Ncm, verified with a manual torque controller to check if the implant stability was sufficient for immediate temporalization. The scanbody was screwed onto the implant and closed using sutures (5-0 polytetrafluoroethylene) to complete the treatment. The surgical procedures were performed by one oral and maxillofacial surgeon.

Restorative Procedures
The implant situation was digitalized using a scanbody (TRI Swiss Implants, Hünenberg, Switzerland; Cerec Primescan, SW 5.2., Charlotte, USA) (Figures 10 and 11).  The screw-retained temporary crown was designed with a CAD/CAM using a dental CAD Software (exocad, SW 3.0 Galway, Darmstadt, German etry had been stored in the CAD Software catalog with default settings for high-density polymer blocks (Telio CAD, Ivoclar vivadent, Schaan, Liechte 12Error! Reference source not found.) and fabricated utilizing a five-ax (imes icore 350i, Eiterfeld, Germany). Consequently, materials without a screw channel can be used. The final restoration was tightened onto the implant with a torque va using a manual torque controller ( Figure 13). The screw access hole was se ytetrafluoroethylene (PTFE) tape and composite resin. The restoration was tric and eccentric movements, and the patient was instructed to avoid exces the healing period. Oral hygiene instructions were given. The dental imp was checked using X-ray ( Figure 14). All the laboratory procedures were one dental laboratory. The restorative procedures were performed by one d The screw-retained temporary crown was designed with a CAD/CAM screw channel using a dental CAD Software (exocad, SW 3.0 Galway, Darmstadt, Germany). The geometry had been stored in the CAD Software catalog with default settings for PMMA-based, highdensity polymer blocks (Telio CAD, Ivoclar vivadent, Schaan, Liechtenstein) ( Figure 12) and fabricated utilizing a five-axis milling unit (imes icore 350i, Eiterfeld, Germany). Consequently, materials without a prefabricated screw channel can be used. The screw-retained temporary crown was designed with a CAD/CAM screw c using a dental CAD Software (exocad, SW 3.0 Galway, Darmstadt, Germany). The etry had been stored in the CAD Software catalog with default settings for PMMAhigh-density polymer blocks (Telio CAD, Ivoclar vivadent, Schaan, Liechtenstein) ( 12Error! Reference source not found.) and fabricated utilizing a five-axis millin (imes icore 350i, Eiterfeld, Germany). Consequently, materials without a prefab screw channel can be used. The final restoration was tightened onto the implant with a torque value of 1 using a manual torque controller ( Figure 13). The screw access hole was sealed wi ytetrafluoroethylene (PTFE) tape and composite resin. The restoration was free fro tric and eccentric movements, and the patient was instructed to avoid excess force the healing period. Oral hygiene instructions were given. The dental implant's p was checked using X-ray ( Figure 14). All the laboratory procedures were carried one dental laboratory. The restorative procedures were performed by one dentist. The final restoration was tightened onto the implant with a torque value of 15 Ncm using a manual torque controller ( Figure 13). The screw access hole was sealed with polytetrafluoroethylene (PTFE) tape and composite resin. The restoration was free from centric and eccentric movements, and the patient was instructed to avoid excess force during the healing period. Oral hygiene instructions were given. The dental implant's position was checked using X-ray ( Figure 14). All the laboratory procedures were carried out by one dental laboratory. The restorative procedures were performed by one dentist.

Discussion
Implant treatment planning has changed in recent years from a surgical approach that focused mainly on bone availability to prosthetic-oriented planning with 3D imaging and CAD software. CBCT has ushered in a new era of diagnostic capabilities in the dental office. Nowadays, a major advantage of implant surgery is the computer-guided, template-assisted surgery, especially in complex situations. Better clinical experiences and evidence-based improved outcomes can be offered to patients with confidence when CTguided dental implant surgery is used [33,34].
The implant placement and the immediate provisionalization require accurate treatment planning. The preoperative digital planning aided in choosing an implant length and diameter that fit within the biologic boundaries position [35,36] and was based on the prosthetic requirements. Assessing the three-dimensional alignment and depth of the first drill, using a pilot-drill surgical template, are crucial steps in the preparation of the implant site. This approach is very helpful for single implants with narrow conditions, as the diameter of the sleeve is reduced, and it can be positioned between two adjacent teeth. The static, computer-assisted immediate implant surgery with the pilot-drill surgical template allowed the clinician to perform the rest of the procedure using freehand techniques and resulted in the present case of a correct three-dimensional implant placement. It must be discussed that a fully guided surgical technique can offer more accuracy and that a certain degree of deviation from the digital planning should be taken into consideration when using a pilot-drill surgical template [37,38]. Primary stability of the implant was reached, which allowed immediate provisionalization in the same appointment.
The aims of fixed immediate prostheses include patient comfort, proper management of soft tissue, and elimination of second-stage surgery [39]. Especially in the field of

Discussion
Implant treatment planning has changed in recent years from a surgical approach that focused mainly on bone availability to prosthetic-oriented planning with 3D imaging and CAD software. CBCT has ushered in a new era of diagnostic capabilities in the dental office. Nowadays, a major advantage of implant surgery is the computer-guided, template-assisted surgery, especially in complex situations. Better clinical experiences and evidence-based improved outcomes can be offered to patients with confidence when CTguided dental implant surgery is used [33,34].
The implant placement and the immediate provisionalization require accurate treatment planning. The preoperative digital planning aided in choosing an implant length and diameter that fit within the biologic boundaries position [35,36] and was based on the prosthetic requirements. Assessing the three-dimensional alignment and depth of the first drill, using a pilot-drill surgical template, are crucial steps in the preparation of the implant site. This approach is very helpful for single implants with narrow conditions, as the diameter of the sleeve is reduced, and it can be positioned between two adjacent teeth. The static, computer-assisted immediate implant surgery with the pilot-drill surgical template allowed the clinician to perform the rest of the procedure using freehand techniques and resulted in the present case of a correct three-dimensional implant placement. It must be discussed that a fully guided surgical technique can offer more accuracy and that a certain degree of deviation from the digital planning should be taken into consideration when using a pilot-drill surgical template [37,38]. Primary stability of the implant was reached, which allowed immediate provisionalization in the same appointment.
The aims of fixed immediate prostheses include patient comfort, proper management of soft tissue, and elimination of second-stage surgery [39]. Especially in the field of Figure 14. Dental X-ray after dental implantation.

Discussion
Implant treatment planning has changed in recent years from a surgical approach that focused mainly on bone availability to prosthetic-oriented planning with 3D imaging and CAD software. CBCT has ushered in a new era of diagnostic capabilities in the dental office. Nowadays, a major advantage of implant surgery is the computer-guided, template-assisted surgery, especially in complex situations. Better clinical experiences and evidence-based improved outcomes can be offered to patients with confidence when CT-guided dental implant surgery is used [33,34].
The implant placement and the immediate provisionalization require accurate treatment planning. The preoperative digital planning aided in choosing an implant length and diameter that fit within the biologic boundaries position [35,36] and was based on the prosthetic requirements. Assessing the three-dimensional alignment and depth of the first drill, using a pilot-drill surgical template, are crucial steps in the preparation of the implant site. This approach is very helpful for single implants with narrow conditions, as the diameter of the sleeve is reduced, and it can be positioned between two adjacent teeth. The static, computer-assisted immediate implant surgery with the pilot-drill surgical template allowed the clinician to perform the rest of the procedure using freehand techniques and resulted in the present case of a correct three-dimensional implant placement. It must be discussed that a fully guided surgical technique can offer more accuracy and that a certain degree of deviation from the digital planning should be taken into consideration when using a pilot-drill surgical template [37,38]. Primary stability of the implant was reached, which allowed immediate provisionalization in the same appointment.
The aims of fixed immediate prostheses include patient comfort, proper management of soft tissue, and elimination of second-stage surgery [39]. Especially in the field of esthetic surgery, such as in the anterior or premolar region, the immediate temporary restoration also offers advantages from an esthetic point of view. The emergence profile is optimally formed by conditioning the peri-implant tissue, and papillae are, thus, formed at an early stage; a clear line between the subgingival and supragingival areas can be seen [40]. The restorations of the novel implant system directly planned on the implant (without abutment) also enable an individual emergence profile for definitive solutions. Although almost all dental implant systems have prefabricated provisional abutments for the fabrication of the fixed interim, these components are time-consuming and costly to handle manually.
In the past, implants were restored using metal abutments and porcelain fused to metal crowns. The use of metal-ceramic components leads to higher material and processing costs. Veneered crowns do not achieve the esthetic perfection of all-ceramic crowns. The trend towards materials with improved biomimetic properties, such as all-ceramic restorations, has enabled us to deliver better esthetic results in terms of the appearance of our restorations [41][42][43][44][45][46][47][48]. Even though modern restoration modalities promise a fully digital workflow, such as scanned implant situations and CAM-fabricated restorations, the latter still needs to be manually cemented or bonded. Today, titanium bases bonded on CAM ceramic abutments or crowns are frequently used. Prefabricated titanium base abutments are adhesively connected to a ceramic abutment (=hybrid abutment) or to a full contour crown (=hybrid abutment crown) [49]. Due to these hybrid abutments, deep submucosal abutment shoulders are avoided and, thus, also excess cementum, which can lead to inflammatory reactions of the gingival tissue with adjacent marginal bone loss [50][51][52].
Although titanium and ceramics are known for their high biocompatibility, the adhesive luting agent may cause irritation, is susceptible to aging [53], and may develop defects at the interface, which, in turn, are susceptible to bacterial colonization [54]. Unpolymerized monomer of the bonding material may have a negative effect on the peri-implant tissue health.
In this context, the idea of a directly screwed interface of the novel implant without adhesive luting seems tempting. However, it should be considered that the direct connection between the implant and the build-up shows always a microgap, even if they are connected correctly [55]. The gap can enlarge over time due to masticatory loading, which can lead to micromovements of the prosthetic components [54][55][56][57]. The microleakage caused by the microgap allows the passage of acids, enzymes, and bacteria [58]. The accumulation of microorganisms around the implant can cause soft tissue infections and bone loss around the implant, which can lead to implant failure [54,56,59].
The fabrication of the provisional restoration from tooth-colored composite or PMMA materials or the definitive restoration with zirconiumoxide of the novel implant system promise an esthetically pleasing restoration. The pink anodized implant surface has a positive effect on gingival esthetics and prevents dark margins. It masks any flashing through the mucosa, which can be confirmed in the present case. The concave design of the implant shoulder may have a positive effect on the surrounding soft tissue. The tapered implant design is suitable for immediate implant placement. As in the present case, it is well designed for narrow gaps with root proximity of the adjacent teeth to avoid injuring anatomical structures [60]. Due to its screw design, it offers a high primary stability even in soft bone situations (D4) as it condenses bone locally, resulting in more implant stability [61,62].
Comparing conventional and digital prosthetic working methods, a reduction in working time can be seen [71]. The intraoral scanning lowers the patient discomfort and procedure time compared to conventional impression taking [72]. Furthermore, the CAM process can reduce the production time and fabrication costs of the restorations [73]. The absence of the abutment of the novel implant system eliminates the step of bonding the restoration in the laboratory and further shortens the working time by using internal computerized techniques even more. In the long run, the supply will be cheaper due to fewer materials and work steps. However, it has to be considered that initial operating expenses are very high. The financial investments for intraoral scanners, CAD/CAM software, license fees, and the milling unit are high in comparison with conventional workflows [5].
In the past, the literature showed that the geometry of the abutment and the presence of a screw channel are critical factors for the success of a fixed dental restoration [74][75][76][77].
Chewing forces might be directly transferred from the crown to the abutment, leading to a higher stress on the screw and the implant-abutment interface [78], whereas another study, examining restorations with Ti-Base abutments, showed that the presence of a screw channel had no clinically relevant impact on the stability of the crown. In this context, the author suspects that the Ti-Base abutment with comparatively sharper edges, a smaller diameter, protection against rotation, and a steeper preparation angle is responsible for this [50]. Therefore, it remains to be seen how the novel implant system behaves in the absence of an abutment and with a direct screw-retained connection between the restoration and the implant.
A limitation of the case report is the narrow diameter of the implant. Narrow diameter implants provide a reduced surface area for osseointegration; they may be at increased risk of overload due to occlusal forces [79,80]. Choosing a 3.3 mm enossal diameter (and 3.7 mm platform diameter) of the implant in the present case should be mentioned. The narrow diameter has been proven to be useful in challenging indications where the width of the alveolar ridge or the interdental space is insufficient. The implant provides more space for the bone and soft tissue in tight conditions [79,81,82]. However, the distance to the adjacent teeth was maintained in this case.
An alternative treatment option for the patient could have been a removable prosthesis. In view of the patient's age, a fixed restoration was agreed upon. The shortened dentition is to be restored at a later date by another implant placement with bone augmentation measures in the molar region. The outcome of the revision treatment of tooth 15 remains to be seen.
Nevertheless, it is a limitation of this novel implant system that data from clinical studies are missing.

Conclusions
The single-unit restorations of the novel implant system can be milled under additional polishing (temporary restorations, e.g., PMMA) or crystallization (final restoration with zirkoniumdioxide) without a time-consuming mechanical attachment to a titanium base. The absence of the cement may have a positive effect on the surrounding tissue and healing. Due to its tooth-colored restoration and the pink anoidized implant surface, they are interesting for highly esthetic situations with fully digital treatment paths. Results from additional clinical studies are required to validate the positive results from these initial clinical experiences.