Dr. Dimitar Filtchev
• Dr. Dimitar Filtchev obtained his degree in Dental Medicine from the Faculty of Dental Medicine in Sofia, in 1998.
• Since then, he has been running a successful private practice in Sofia, focused on Implantology and Esthetic Dentistry.
• He has more than 80 publications in scientific journals, many scientific presentations at international dental congresses, numerous participations as an invited speaker at national and international congresses.
• He is also a DDS Ambassador.
Dr. Elitsa Ruseva, Dr. Metodi Abadzhiev Jr.
introduction
Restoring a lost tooth in the frontal area is a great challenge for every dentist. There are many different approaches according to the initial clinical situation. We often need to deal with bone defects and dehiscences. The risk of losing soft tissue volume and vestibular bone height is unacceptable due the high aesthetic requirement. Patient compliance is always important for achieving long-term success.
Preserving the alveolar ridge is one of the primary goals of immediate implant placement. A number of studies, Bäumer D, Hürzeler M, Zuhr O (2017)(1)(9), have shown that immediate implantation in fresh extraction sockets yields a prognosis similar to that of implants placed in healed extraction sites.
The combination of the retained buccal root fragment of the extracted tooth with immediate implant placement may be an effective means of alveolar ridge preservation.
One of the challenges in prosthetic dentistry and implantology is the restoration of a lost tooth in the frontal area due to the soft and hard tissues remodeling after tooth extraction. The rapid loss of bone height and soft tissue volume is a constant threat. That’s why conventional immediate implant placement in the frontal area was the gold standard for decades in such cases. To keep the volume of the tissues, Hürzeler et al, 2010(2) published the “socket shield” technique where a tooth root section is prepared simultaneous to immediate implant placement. This has demonstrated histologic and clinical results that are highly promising for esthetic implant treatment. In their 2018 study, Gluckman H, Salama M(3) showed high success rates in analogical cases with PET (Partial Extraction Technique). Lately, with the development of surgical templates, guided implant placement can be combined with the socket shield technique to obtain long lasting and predictable results.
“One of the challenges in prosthetic dentistry and implantology is the restoration of a lost tooth in the frontal area due to the soft and hard tissues remodeling after tooth extraction.”
Clinical research conducted by Gluckman H, Salama M, et al.(4) suggests that retaining roots of teeth deemed hopeless may prevent tissue alterations following tooth extraction. Consequently, this proof-of-principle experiment aimed to histologically evaluate the effectiveness of a partial root retention technique (known as the socket shield technique) combined with immediate implant placement which was proven by Bäumer D, Zuhr O et al.(5) showing histological evidence.
According to the findings of that study, the outcomes are promising: the implants successfully fused with the bone tissue without eliciting any histologic inflammatory reactions, and there were no indications of resorption processes in the tooth fragment. Moreover, on the outer side (buccal) of the tooth fragment, it adhered to the buccal bone plate through a natural periodontal ligament. Additionally, on the inner side (lingual) of the fragment, the presence of newly formed cementum was observed. In regions where the implant intersects with the fragment, newly formed cementum was directly observed on the implant surface.
the case
In January 2023, a 29-year-old male patient in good general health came in the office with pain in the central left incisor. The intraoral examination showed noun in the area of tooth 21. On the buccal-cervical surface an old composite restoration was found.
The initial radiographic examination and cone beam computed tomography (CBCT) analysis conducted before treatment indicated insufficient external root resorption of the same tooth. Following this assessment, various treatment options were subsequently discussed.
After case planning, it was decided to go for a socket shield technique and immediate implant placement using a surgical guide instead of extraction.
The treatment plan involved conservatively removing the palatal root fragment along with the remaining buccal part of the root. The pulp chamber served as an initial guide to ensure maximum control and simplify the osteotomy process. Once the implant site was fully prepared to the required depth, 0.5mm above the bone level, the remaining root was carefully sectioned both mesially and distally using a Lindemann Bur (Hu-Friedy) and then removed, leaving only the 2/3 buccal aspect intact. This preserved buccal part of the root was then prepared using the Touati bur vestibular with a BOPT(11).
The surgery was performed using an implant surgical and prosthetic guide. The digital planning was done by our team according to the prosthetically driven implantology concept.
By utilizing the RealGuide software (3Dieme, Italy) and merging the .dicom (Digital Imaging and Communications in Medicine) and .stl (Standard Tessellation Language) files, we generated 3D printed surgical and prosthetic guides. The main purpose of the prosthetic guide is to validate the right prosthetic position of the implant during surgery and to be used as an immediate provisional restoration.
The implant used was the TSV (ZimVie, USA) with dimensions of 4.1x16mm. It was placed through the surgical guide according the fully guided protocol using the usage of RealGUIDE Z3D Guided Surgery Kit. The implant was placed slightly palatal, to avoid contact with the shield, 1mm more apical from the remaining root structure.
Following placement, the implant was covered with a customized healing abutment. This customized abutment ensured a proper emergence profile, eliminating the need for implant uncovering and promoting improved healing.
“The main purpose of the prosthetic guide is to validate the right prosthetic position of the implant during surgery and to be used as an immediate provisional restoration.”
During the initial healing phase and osseointegration, a prosthetic guide was utilized as a temporary Maryland bridge. This temporary bridge was designed to be out of occlusion to ensure minimal disturbance during this critical period.
After three months of healing and osseointegration, the implant was scanned using an iTero Element™ 5D Plus scanner (Align, USA) along with a Zfx screw-retained scanbody (ZimVIE,USA). The scan focused on the emergence profile and the implant itself. Based on the scan data, a screw-retained provisional crown was made, then placed, using exocad software (Align, USA).
The temporary restoration remained in place for two months to allow for the final shaping of the soft tissue profile. Subsequently, the next step involved scanning for the permanent crown, following the 3 scan technique: first scan of the provisional restoration, second scan of the emergence profile and third scan of the scanbody.
The final restoration procedure was carried out by MDT Vincent Fehmer in Geneva, Switzerland. A single screw-retained monolithic stained zirconia crown (Prime, Ivoclar Vivadent, Liechtenstein) was crafted on a Ti Base with 0.3mm height (Gentec, ZimVie, USA).
After 1 year of function, there was no chipping or cracking found.
discussion
The suggested method shows a modification of the socket shield technique approach for a compromised maxillary central incisor.
Changes to the alveolar ridge typically occur following tooth extraction in infected sites, necessitating tissue grafting once the infection has been completely eradicated. This grafting procedure is often performed as part of a second surgery several weeks after the extraction. However, this waiting period can be inconvenient for the patient due to the necessity of the grafting procedure and the compromised nature of the provisional restoration, which may be a denture or an Essix retainer.
Various studies have explored different techniques for preserving ridge volume after tooth extraction. Some authors propose submerging part of the roots, even vital ones, to aid in maintaining the ridge’s volume and supporting future prosthetic solutions, such as pontic site development. One notable technique gaining attention is the Partial Extraction Therapy (PET) approach, Gluckman H, Salama M et. al(6). This method aims to conserve the periodontal ligament to prevent resorption of the buccal bone plate, thereby preserving the natural contour of the alveolar process. By retaining a portion of the tooth root structure, PET may offer advantages in preserving bone and soft tissue architecture for future implant placement or other restorative procedures.
Moreover, research has investigated the long-term outcomes of dental implants inserted through impacted teeth. Remarkably, studies with follow-ups of up to 8 years have reported no signs of inflammation or bone resorption around these implants. Histological analysis of these implants has shown intimate contact between the implant surface and the retained root structure, with the formation of cementum on the implant surface indicating a favorable healing response. These findings collectively suggest that techniques like PET and socket shield procedures do not negatively impact the function or biology of titanium oral implants, at least in the short term. Such insights are crucial for advancing dental treatment approaches aimed at preserving natural tooth structures and optimizing outcomes for patients undergoing implant therapy(7)(8)(9)(10).
The technique used in this clinical case involves drilling through the root to position the implant palatally. This allows for the creation of a screw-retained crown and helps preserve the buccal part of the root, reducing the risk of cortical bone changes.
“The technique used in this clinical case involves drilling through the root to position the implant palatally. This allows for the creation of a screw-retained crown and helps preserve the buccal part of the root, reducing the risk of cortical bone changes.”
In cases like these, preserving tissue over time becomes paramount to avoid the need for tissue augmentation. The bundle, the shield with the whole root periodontal structure gives stability to the vestibular bone and soft tissue, keeping the same structure, like it was before extraction, making the long-term result very predictable. The BOPT technique [11] prepares the buccal wall, allowing the tissues to additionally grow on the vestibular surface of the root, making the vestibular stability of the tissue thicker and avoiding the chance of exposing the shield. The technique applied in this case allowed us to maximize tissue stability and minimize surgical intervention. Utilizing surgical templates, we have the possibility to plan our perfect implant position in the narrow space palatal to the shield. The preciseness of the 3D printed templates has been shown through various studies, measuring the deviation between the actual implant position and the planned one.
According to Colombo et al.’s 2017 study [12], the use of surgical templates is still not proven, with no statistically significant differences between conventional and computer-guided implant placement procedures, both for patient outcomes and implant survival rate. However guided implant surgery may be recommended in cases where minimally traumatic or flapless surgery is desired – optimal positioning of the implant is crucial. Another big advantage of guided surgery is the stability of the drill. Some of the complications with this technique occur after an undesired pressure on the shield with either the drill or the implant. The stability of the drill that the guide gives to the clinician makes the execution of that technique much more predictable. The almost parallel, non-aggressive shape of the implant, also minimizes the possibility of touching and breaking the shield or the bundle structure.
Thanks to the utilization of intraoral scanning (IOS) and the 3 scan protocol, the technician achieved a precise replication of the emergence profile attained with the provisional restoration. This allowed for the creation of a perfect coping, ensuring seamless integration with the surrounding tissues. The control visit after 1 year showed perfect stability of the bundle structure, having the same vestibule profile like the adjacent teeth, which would have been very difficult to achieve with predictability using any other technique.
In this case report, a maxillary central incisor deemed unsalvageable was replaced by immediately placing an implant using the socket shield technique and a surgical template. A Ti-base with a monolithic Zirconia crown was utilized. Despite a thin biotype, the peri-implant tissues were well preserved over time, resulting in a successful outcome to the patient’s satisfaction. With certain limitations and careful case selection, this treatment approach appears promising for addressing aesthetically challenging anterior single implant restorations.
conclusion
This case report presents a modified socket shield technique for a compromised maxillary central incisor. After tooth extraction, preserving ridge volume becomes crucial, often necessitating tissue grafting. Techniques like Partial Extraction Therapy (PET) aim to maintain ridge volume by conserving the periodontal ligament. Long-term studies show positive outcomes for implants placed through retained roots. The technique described involves drilling through the root to position the implant palatally, preserving tissue and minimizing surgical intervention. Surgical templates ensure precise implant placement, though studies on their efficacy show mixed results. In this case, an unsalvageable incisor was replaced using the socket shield technique with a surgical template, resulting in successful
REFERENCE NOTES
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