Digital design of a hybrid bone and tooth-supported surgical guide in patients with unilateral few remaining natural teeth: a dental technique.

A technique for the design of a hybrid tooth and bone-supported implant drilling guide is described. The patient was scanned using cone beam computed tomography and an optical intraoral scanner. The dicom file was segmented according to the area of interest composed of bone and the remaining natural teeth. The Standard Tessellation Language (STL) file was trimmed to only the teeth providing support, followed by merging between the bone and teeth files in one STL. The implant drilling guide was designed with the Real Guide software program, and the file was 3-dimensionally printed in clear surgical guide resin. This technique offers an accurate, cost-effective digitally designed implant placement guide for patients with long-span distal extension edentulous areas and few remaining natural dentitions providing distal bone support. It can also be used in patients with hemi maxillectomy for zygomatic implant placement. This type of surgical guide provides more accuracy in implant surgeries that require flab elevation by gaining more support from the remaining natural dentition.

Guided immediate implant with and without using a mixture of autogenous and xeno bone grafts in the dental esthetic zone. A randomized clinical trial.

PURPOSE: This in vivo study aims to assess the pink esthetic score in the anterior maxilla after computer-guided immediate implant installation and fully digital immediate temporalization with and without grafting the jumping gap with a mixture of 1:1 autogenous and xenograft particulates. MATERIALS AND METHODS: Twenty-four patients with non-restorable upper anterior teeth in the aesthetic zone have undergone a traumatic extraction for the non-restorable tooth followed by immediate implant placement using a 3D-printed surgical guide according to prosthetically driven implant placement. The patients were divided into two groups. The study group received the dental implant after grafting the jumping gap with 1:1 autogenous and xenograft particulates, while the control group received the dental implant without grafting the jumping gap. Each patient received a digitally fabricated, immediate, nonfunctional temporary prosthesis. The esthetic outcome was compared between the two groups using the pink esthetic score at implant insertion and after 6 months of follow-up. Statistical comparisons were carried out between the studied groups using the Mann-Whitney U test. RESULTS: Immediately postoperatively, there was no statistically significant difference between the median PES in the two groups (P-value = 0.746). After six months, the study group showed a statistically significantly higher median PES than the control group (P-value = 0.048). CONCLUSIONS: Grafting the jumping distance in the immediate implant protocol helps achieve a better esthetic outcome. CLINICAL RELEVANCE: The use of immediate guided implant placement along with grafting the jumping gap followed by immediate digital temporalization guarantees a better esthetic outcome while preserving time, cost, and the number of clinical visits. TRIAL REGISTRATION: The study was registered on clinicaltrials.gov with registration number NCT04096209. (19/9/2019).

Novel CAD-CAM fabrication of a custom-made ball attachment retentive housing: an in-vitro study.

PURPOSE: This study aims to evaluate the digitally designed ball attachment housing in its initial retentive force and after 2 years of simulated clinical use and to compare it with the regular nylon ball attachment housing. MATERIALS AND METHODS: Twenty implants with their corresponding ball abutments (diameter 4.5 × 4.0 mm) were inserted in resin blocks. They were divided into two groups. In Group I, ten ball abutments each received their corresponding conventional attachment with nylon rings. In Group II, ten ball abutments received the novel CAD-CAM polyetheretherketone ball attachment housing. A universal testing machine was used to measure the retention force. The achieved maximum values of retention force were recorded at the beginning of the study (initial retention) and after 2 years of artificial ageing (2000 cycles of insertion and removal). Results were statistically analyzed using an independent sample T test. RESULTS: The PEEK attachment housing showed high retention forces (25.12 ± 0.99 N) compared to the conventional attachment with a nylon ring (15.76 ± 0.93 N) in the initial dislodgement test. There was a statistically significant difference in mean retention at the initial retention test and after 2 years of stimulated usage between the two studied groups, p = 0.000. CONCLUSIONS: Within the limitations of this study, the novel CAD-CAM-PEEK attachment showed high retention characteristics compared to the conventional attachment with nylon rings, initially and after simulated long-term use.

Augmentation of single tooth extraction socket with deficient buccal walls using bovine xenograft with platelet-rich fibrin membrane.

BACKGROUND: Different techniques and materials such as bone grafts and bioactive agents have been used for alveolar ridge augmentation in extraction sockets with a defective wall, there is not a specific material or technique that has resulted in superior outcomes or prevented total bone loss. OBJECTIVES: This clinical study aims to evaluate radiographically the effectiveness of using bovine xenograft with platelet-rich fibrin (PRF) membrane on vertical and horizontal alveolar ridge dimensional changes following tooth extraction that are complicated by buccal bone loss. MATERIALS AND METHODS: This study was conducted in Egypt on fourteen patients with a single posterior tooth indicated for extraction. A preoperative cone-beam computed tomography (CBCT) scan confirmed more than 50% loss in buccal bone in each tooth. Extraction sockets were packed with minced PRF clots mixed with a bovine xenograft. Each extraction socket was sealed by PRF membranes. CBCT scans, performed before tooth extraction and after 6 months, were used to assess alveolar ridge changes both vertically and horizontally. RESULTS: There was a significant gain in the buccal and middle of the extraction socket bone height, recording 86.01% (6.33 mm) and 206.45% (9.6 mm), respectively. There was an insignificant bone loss in the lingual bone height and width, recording - 8.49% (-1.06 mm) and - 13.39% (1.05 mm), respectively. The results also showed a non-significant decrease in alveolar bone density (-14.06%) between pre-operative bone present apical to the extraction socket and newly formed bone inside the socket. CONCLUSIONS: Ridge preservation/augmentation techniques using a bone graft mixed with PRF and covered by PRF membranes in fresh extraction sockets complicated by the loss of buccal bone result in buccal bone augmentation and a reduction in horizontal and vertical ridge collapse after tooth extraction. CLINICAL RELEVANCE: The bovine xenograft in conjunction with PRF can be used immediately after extraction for ridge preservation, providing adequate bone width and height for implant placement.

Fabrication of a reverse-engineered custom scan body as a digital solution for recording implant position: A dental technique.

A technique for the reverse engineering of the implant-abutment connection to fabricate a custom scan body is described. The implant-abutment connection was designed using the exocad software program, the scan body with screw channel was designed with the Blender software program, and the file was either 3-dimensionally printed in definitive tooth-colored resin with ceramic filler material or milled in polyetheretherketone (PEEK). This technique offers an accurate, cost-effective digital solution for implant optical scanning that can replace prefabricated scan bodies that may not be available for all implants. (J Prosthet Dent xxxx;xxx:xxx-xxx).

Retrospective digital study of mandibular flexure in patients with long-span fixed restorations supported by natural teeth.

PURPOSE: This retrospective study aims to evaluate the mandibular flexure on a long-span rigid fixed prosthesis supported by natural teeth. MATERIALS AND METHODS: Nine patients (five males and four females) were included in this study who had long-span rigid mandibular fixed prostheses for long-term (10-15 years) that have led to radiographic changes around the supporting teeth. The mandibular flexure was measured digitally after adhering reference markers to the prostheses. Intraoral scans were obtained at the minimum and maximum mouth openings before and after splitting the preexisting prostheses. The distances between the markers were measured, and mandibular flexure was calculated. RESULTS: This study showed a significant deviation (narrowing) of the mandible before and after splitting the rigid fixed prostheses (P value < 0.05). CONCLUSION: Digital analysis of the data collected from the patients in this retrospective study indicated that deviations occur during mandibular flexure. CLINICAL RELEVANCE: Splitting the full arch prosthesis could prevent the negative consequences of mandibular flexure on restorations. Trial registration The study was registered on clinicaltrials.gov with registration number NCT05617274 (15/11/2022).

Digital design and manufacture of a stackable implant surgical guide for immediate loading in completely edentulous full-arch cases: a dental technique.

The design and manufacture of a stackable surgical guide for implant placement with immediate prosthetic loading of completely edentulous cases is described in this dental technique. To achieve this, the stackable attachment is designed using free-form designing software, which is later joined to the implant placement guide and the dental prosthesis. This technique should provide the patient with a same-day implant and an esthetic restoration accurately placed in the predesigned position of the centric occluding relationship. It also reduces the number of visits and prosthetic complications related to the improper implant position.

Digital duplication of maxillary complete denture: A dental technique.

OBJECTIVE: This technique aims to construct a virtual, well-adapted maxillary denture from an existing, ill-fitting denture in completely edentulous patients. CLINICAL CONSIDERATIONS: A functional impression is made using the loose maxillary denture, and a cone beam computed tomography (CBCT) of the entire old denture is carried out. The obtained digital imaging and communication in medicine (DICOM) file was segmented using an image computing platform software (3D slicer). The resultant Standard Tessellation Language (STL) file was 3D printed in porcelain white-like resin, then colored and characterized. CONCLUSIONS: The technique introduces a high-quality digital denture replicate with good retention, that can replace the traditional duplication technique. It can also be used as a relining method for old dentures. This proposed digital technique reduces the number of clinical appointments while also providing a digital library for future denture manufacture. CLINICAL SIGNIFICANCE: The proposed technique offers a high-quality digital denture replicate that can replace the traditional duplication technique. This digital technique also reduces the number of clinical appointments required for denture duplication.

Retention of Different Attachment Systems for Digitally Designed Mandibular Implant Overdenture.

PURPOSE: Primary retention and gradual loss of retention of different attachment systems are important key factors in proper attachment selection; however, studies on attachment retention show a wide range of retention values concerning the same attachment system. This in vitro study uses a novel approach that utilizes a digitally designed and 3D-printed reinforced overdenture, which has a digitally determined geometric center, in order to standardize results for future research and clinical work. This study aims to evaluate initial retention along with the gradual loss of retention at different time intervals between three types of stud attachments, retaining a digitally designed, reinforced mandibular overdenture after 5475 cycles simulating 5 years of attachment usage. MATERIALS AND METHODS: An epoxy model of an ACP Class I (American College of Prosthodontists) edentulous mandible was constructed. A fully computer-designed surgical guide was employed after virtual denture design to place two implants according to prosthetically driven implant placement protocol. A metal meshwork with tissue stops was designed digitally to reinforce the denture and to carry the geometric center. The meshwork was incorporated into the denture-intaglio surface, which was planned for attachment pickup. Forty-eight digitally designed and metal-reinforced 3D-printed dentures were divided into four groups (12 dentures for each group). Loss of retention was measured to compare two novel Locator attachments (12 pairs of Locator R-TX, 12 pairs of Locator F-TX medium and low retention, with 12 pairs of ball and socket). Each group was subjected to an insertion and removal fatigue test resembling 5 years of patient usage. Retention values were recorded using a universal testing machine. RESULTS: Locator F-TX medium and low retention showed loss of retention by 91.93% and 92.91%, after fatigue testing equivalent to 2 and 3 years of use, respectively. Ball and socket and Locator R-TX showed loss of retention by 19.87% and 26.31%, respectively, after fatigue testing equivalent to 5 years of use. CONCLUSIONS: Locator R-TX attachment systems showed promising retention for implant overdentures compared to ball and socket attachments. The proposed digital technique of denture reinforcement is capable of standardizing results for research and clinical work.

Digital Designing of a 3D-Printed Stackable Ear Mold for Auricular Rehabilitation: A Technical Note.

A technique for the virtual design of a three-piece stackable auricular mold for unilateral auricular defect rehabilitation using an open-source software program is described. An optical intraoral scanner is used to scan the patient's ear on both the affected and unaffected side. To maintain the relationship between the mold parts, a stackable attachment is designed and joined to the mold. The mold is 3D printed in resin. This technique provides the patient with a precise auricular prosthesis with perfect thickness, adaptation, and appearance. The workflow introduced in this technique could be considered as an alternative way to fabricate auricular prostheses in a much shorter clinical and laboratory time compared to the conventional workflow. Int J Prosthodont 2023;36:637-641.

Digital assessment of the accuracy of implant impression techniques in free end saddle partially edentulous patients. A controlled clinical trial.

OBJECTIVES: This in vivo study aims to assess the accuracy of the digital intraoral implant impression technique, the conventional closed-tray impression technique, and open-tray impression techniques in a standardized method of data segmentation along with the best-fit algorithm to overcome the inconsistency of results of previous studies regarding implant impression techniques. MATERIALS AND METHODS: Sixteen implants were placed in eight patients. Each patient has undergone four impression techniques: direct intraoral scanning of the stock abutment, intraoral scanning using a scan body, conventional closed tray impression technique, and the conventional open tray impression technique. The conventional impressions were poured into stone casts with analogues and stock abutments and scanned using a desktop scanner. In intraoral scanning of the scan body, computer-aided design software was used for the replacement of the scan body with a custom-made abutment that is identical to the stock abutment, allowing comparison with the other impression techniques. The deviation in implant position between the groups was measured using special 3D inspection and metrology software. Statistical comparisons were carried out between the studied groups using a one-way analysis of variance (ANOVA) test. RESULTS: The total deviation between groups was compared to the reference group represented by the intraoral scanning of the abutment. The total deviation was statistically significantly different (P = 0.000) among the different studied groups. The mean deviation was recorded as 21.45 ± 3.3 µm, 40.04 ± 4.1 µm, and 47.79 ± 4.6 µm for the intraoral scanning of the scan body, the conventional closed, and open tray, respectively. CONCLUSION: For implant impressions in partially edentulous patients, intraoral oral scanning using a scan body significantly improves scanning and overall accuracy. Regarding conventional impressions, the closed-tray impression techniques showed more accuracy than conventional open-tray impressions. CLINICAL RELEVANCE: Intraoral digital implant impression using scan body offers more accuracy than conventional implant impression techniques for recording posterior implant position in free-end saddle partially edentulous patients.

Accuracy of digital auricular impression using intraoral scanner versus conventional impression technique for ear rehabilitation: A controlled clinical trial.

PURPOSE: This research aims to compare the accuracy of different auricular impression techniques used to produce either a mirror image of the unaffected ear or a surgical stent and template for auricular rehabilitation. The research compares two digital ear impression techniques using an Intra-Oral digital Scanner (IOS) (with /without markers) versus a traditional technique using hydrocolloid impression materials. MATERIAL AND METHODS: Eight participants were selected with intact right ears. Patients' right ears were digitally scanned with an IOS, once with resin markers and once without markers. A conventional auricular impression was taken for each participant, which was then scanned using a desktop scanner. The digital IOS technique with markers was set as a reference model. Total 3D deviations between the study groups were calculated using Geomagic control software (software for 3D coordinate measuring technology). An independent sample t-test was used to make comparisons between the two tested groups. RESULTS: The conventional impression and the intraoral scan without markers recorded a mean of 1.4057 ± 0.3581 and 0.7605±0.1469, respectively, of total 3D deviation from the intraoral scan with markers. There was a significant difference in auricular impression accuracy between conventional and intraoral scans without markers. CONCLUSIONS: Using intraoral scanners facilitates impression acquisition and increases the accuracy compared to traditional hydrocolloid impression techniques, which may affect the shape of tissue due to its liability to be compressed by the impression material. Using markers allows for very precise data collection, reducing stitching complications that affect the accuracy of scans taken without markers. CLINICAL SIGNIFICANCE: The proposed technique for auricular digital impression using an intraoral scanner guarantees a fast technique with accurate results in acquiring anatomical data for the rehabilitation of ear defects. This research was registered on clinicaltrials.gov with the following registration number: NCT04893902.

Retention of bar clip attachment for mandibular implant overdenture.

OBJECTIVES: The aim of the present study was to evaluate the retention and loss of retention after fatigue testing at different time intervals between two types of bar clip materials (digitally designed PEEK bar clip and regular Nylon bar clip). MATERIALS AND METHODS: An epoxy model was constructed for a completely edentulous mandible. Two implants were placed according to prosthetically driven implant placement by a computer-guided surgical stent. Bar clips were digitally designed, 3D printed, and pressed into Poly Ether Ether Ketone (PEEK). Pick up of PEEK and nylon clips was performed on the dentures fitting surface using self-cured acrylic resin. Each study group was subjected to an insertion and removal fatigue test simulating 3 years of patient usage. Retention values were recorded using the universal testing machine at initial retention and after 1, 2, and 3 years of simulated usage. For proper sample sizing, 24 models and dentures (12 for each group) were used. An independent sample t-test and repeated measures analysis of variance were used to compare the data. RESULTS: There were statistically significant differences in retention between the PEEK and nylon bar clips at the beginning of the experiment (p = 0.000*). But after 3 years of simulated use, there was no significant difference in retention between the test groups (p = 0.055, NS). After 3 years of simulated use, the retention of PEEK clips decreased by - 58.66% recording 17.37 ± 1.07 N, while the retention of nylon clip increased by + 2.99% recording 16.56 ± 0.88 N. CONCLUSION: The digitally designed PEEK clip showed comparable retention results to the nylon clip after 3 years of simulated use. CLINICAL RELEVANCE: Maintenance of bar attachment with PEEK clip offers a clinical solution after the wear of normal plastic clips, which is a cheap solution that is easily fabricated and picked up into the denture. Digital fabricated PEEK bar retentive inserts can be used in cases of bar attachment wear.

Digital fabrication of polyetheretherketone retentive bar attachment inserts as overdenture maintenance: A dental technique.

A technique for the virtual designing of retentive attachment inserts for bar-retained 2-implant mandibular overdentures is described. The bar attachment is scanned intraorally, the retentive insert designed with the MESHMIXER software program, and the file 3D printed in resin, which is replicated in polyetheretherketone (PEEK). The technique offers high-quality inserts with good retention that can replace the conventional nylon inserts and reduce the number of maintenance visits and the frequency of changing the bar attachment.