Assessment of Narrow-Diameter Implants Placed in the Posterior Region for Rehabilitation with a Single Crown: A Retrospective Cross-Sectional Clinical Study.
Aug 2026· The International Journal of Oral and Maxillofacial Implants· Vol 0 0, pp.
1-23
· 0 citations
Medicine
TL;DR
NDIs in the posterior regions rehabilitated with a single-unit crown are a reasonable, reliable, and feasible option for oral rehabilitation.
Abstract
Objective
Alveolar ridge atrophy is the result of extensive bone resorption. In cases where the available bone does not allow placement of standard-diameter implants without grafting, short and extra-short implants or narrow-diameter implants (NDI) may be used. NDIs exhibit high survival rates, reaching 95.5% after a nine-year follow-up. Thus, the goal of the present study was to evaluate outcomes of NDIs rehabilitated with a single crown in the posterior regions of the maxilla and the mandible.
Materials And Methods
Patients treated with Ti-Zr NDIs in the posterior region with single crowns were screened. Radiographic and clinical examinations were performed to evaluate marginal bone loss (MBL), peri-implant probing depth (PPD), bleeding on probing (BoP), mobility, palpation, and percussion. Digital images were analyzed to measure and evaluate proximal bone loss. The implants were divided into groups: Group I (Success), II (Satisfactory), III (Compromised), and IV (Failure). The Kruskal-Wallis test was used (p=0.05).
Results
A total of 25 patients (56 Ti-Zr NDIs) were evaluated (mean follow-up: 3.3±1.1 years), with 100% survival rate; no mobility or pain was observed. The mean PPD was 2.11±0.65 mm, and BoP was present in 79.2% of cases. Radiographic analysis showed a mean mesial MBL of 0.83 ± 0.64 mm and a distal MBL of 0.91±0.78 mm. No significant correlation was found between MBL and PPD (p=0.45) or BoP (p=0.26). According to the success criteria, 91% (n=49) of implants were classified as successful (Group I), 7% (n=4) as satisfactory (Group II), and 2% (n=1) as compromised (Group III), with no failures recorded.
Conclusion
NDIs in the posterior regions rehabilitated with a single-unit crown are a reasonable, reliable, and feasible option for oral rehabilitation.
Immediate placement of extra-wide diameter implants in posterior molar sites demonstrated high survival rates and maintenance of crestal bone levels above the implant platform, suggesting this approach is a predictable treatment option.
Katherine Sue Hanser, D. Miley, Robert L. Blackwell et al.· Journal of Advances in Denta...· 0 citations
Conventional screw- and cement-retained single implant restorations are associated with biological and technical complications. Friction-retained conometric concepts have been proposed as an alternative; however, clinical evidence for single crowns, particularly from prospective multicenter studies, remains limited. This study evaluated the 1-year clinical performance of a conometric retention system for implant-supported single crowns. This prospective multicenter study was conducted at nine clinical centers in Europe and North America. Subjects requiring single-tooth replacement in the maxilla or mandible received one implant restored with a prefabricated 5.9° conometric abutment and a titanium nitride–coated coping. All-ceramic crowns were extraorally bonded and seated without cement or screws. Radiographs were obtained at implant placement, delivery of the permanent restoration, and after 1 year. Primary outcomes were implant and prosthetic survival. Secondary outcomes included marginal bone level (MBL) changes, bleeding on probing, plaque, probing pocket depth, and complication rates. Descriptive statistics and confidence intervals were calculated. A total of 144 implants were included in the per-protocol analysis. Three implants failed after delivery of the permanent restoration, resulting in a 1-year implant survival rate of 96.7%. Of 131 restorations evaluated at 1 year, 4 showed irreversible loss of conometric retention and were classified as prosthetic failures. In total, 22 prosthetic complication events were recorded, including 18 reversible technical complications (12.5%) and 4 irreversible failures, corresponding to an overall complication rate of 15.3%. Mean MBL change was − 0.11 mm from implant placement to PR and − 0.02 mm from PR to 1 year. Within the limitations of this 1-year analysis, the investigated conometric retention system demonstrated high implant and prosthetic survival rates and limited marginal bone changes. However, a clinically relevant incidence of technical complications, including irreversible loss of conometric retention, was observed during the first year of function. These findings suggest that the conometric concept may require careful case selection and clinical monitoring. Long-term follow-up is required to further evaluate the clinical stability and prosthetic reliability of this retention concept over time. Trial registration: ClinicalTrials.gov, ID, NCT04063878, August 20, 2019.
Peter Gehrke, Octavio Weinhold, Pelayo Antuna et al.· International Journal of Imp...· 0 citations
Insufficient bone width is a common obstacle when placing dental implants. Numerous methods have been devised to enhance bone thickness. Autogenous bone is considered the benchmark material owing to its superior properties. The split bone block technique showed favorable results in bone gain, although donor site morbidity and the need for a second surgical site were major concerns. The study aimed to assess bone augmentation in the anterior mandible, using the symphysis as both the donor and recipient site, while the original technique required two surgeries. This prospective, single-center, formal consecutive case series study focused on outcomes and involved 11 patients, each having a bone width of less than 4 mm in the anterior mandibular area. Patients underwent a procedure for horizontal ridge augmentation, with implants being placed after a four-month interval. The study assessed the healing of the surgical site, reported complications, and measured pain levels using a visual analogue scale. It evaluated bone gain in width, primary stability, secondary stability of implants, short-term implant success, and augmented bone stability. The current study revealed postoperative swelling occurred in 45.5% of patients, while hematoma and flap dehiscence were each observed twice. Visual Analog Scale pain scores decreased over two weeks (P < 0.001). Mean radiographic bone width increased from (3.27 ± 0.80 mm) preoperatively to (5.88 ± 0.82 mm) at 4 months (P < 0.001). Furthermore, mean implant stability quotient scores improved from 72.80 (3.94) to 88.90 (2.10) (P < 0.001). The short-term implant success was 90.9%, and the mean linear augmented bone stability was 88.41% ± 6.24% (median: 90.57%), with individual values ranging from a minimum of 74.39% to a maximum of 94.57%. The findings of this preliminary case series suggest that the auto-augmentation technique from the mandibular symphysis is a technically feasible protocol for horizontal ridge augmentation. By confining the surgery to a single localized window, it achieves adequate bone gain while minimizing donor-site trauma and optimizing patient recovery profiles. The trial was registered on 12/09/2024 at clinicaltrials.gov (ID: NCT06727591).
Hossam Saleh, R. Eldibany, Dina M N Metawie· BMC Oral Health· 0 citations
BACKGROUND
Rehabilitation of the atrophic posterior maxilla presents a significant clinical challenge. While standard implants combined with sinus floor elevation (SFE) represent a highly predictable treatment modality, they are often associated with increased surgical morbidity, longer treatment times, and higher costs. Consequently, short implants (≤ 8 mm) have emerged as a promising, minimally invasive alternative.
OBJECTIVE
To systematically evaluate and compare the clinical outcomes of short implants (≤ 8 mm) versus standard implants with SFE in the severely atrophic posterior maxilla.
METHODS
This systematic review and meta-analysis was conducted in strict accordance with the PRISMA guidelines. A comprehensive literature search yielded 517 records, from which eligible randomized controlled trials (RCTs) were identified. The primary outcomes evaluated were implant failure rates and marginal bone loss (MBL). Statistical analyses were conducted utilizing a random-effects model, and risk of bias was assessed using the Cochrane RoB 2.0 tool.
RESULTS
A total of 8 RCTs were included in the meta-analysis. Pooled data revealed no statistically significant difference in overall implant failure rates between the short implant group and the standard implant with SFE group (RR = 1.05, 95% CI: 0.68 to 1.75, P=0.83),with low heterogeneity (I2 = 0%). Furthermore, short implants exhibited significantlyless marginal bone loss (MD = -0.15 mm, 95% CI: -0.26 to -0.04, P = 0.008), withan I2= 0%.
CONCLUSIONS
Short implants (≤ 8 mm) serve as a predictable and reliable alternative to standard implants with SFE in the atrophic posterior maxilla. They achieve comparable implant survival rates while offering the distinct clinical advantage of significantly reduced marginal bone loss, supporting their use as a primary minimally invasive treatment option.
Chao Wang, Ce Xin, Naixuan Zhang et al.· Journal of Stomatology Oral...· 0 citations
AIM
To compare the clinical outcomes of digitally assisted immediate implant placement in the posterior mandible using immediate (Type A) and delayed (Type C) loading protocols.
METHODS
Eighty-two patients requiring five-unit fixed partial dentures supported by three implants were consecutively enrolled. All cases were planned using a fully digital workflow integrating CBCT, intraoral scanning, and static computer-guided surgery. Only implants achieving adequate primary stability (insertion torque ≥25 Ncm and/or ISQ ≥60) were included. Patients were assigned to either immediate or delayed loading protocols. Implant survival, marginal bone loss (MBL), plaque index (PI), bleeding on probing (BOP), and probing depth (PD) were evaluated over variable follow-up periods according to the timing of patient enrollment and treatment completion.
RESULTS
A total of 246 implants were placed, yielding an overall survival rate of 97.5% with no significant differences between loading protocols. Mean MBL was 0.7 mm and remained comparable between groups. Peri-implant parameters, including PI, BOP, and PD, were stable throughout follow-up. Regression analysis identified restorative angles >30° as the only significant predictor of increased MBL.
CONCLUSION
Digitally guided immediate implant placement in the posterior mandible demonstrated high survival rates and favorable peri-implant outcomes with both Type A and Type C loading protocols.
CLINICAL SIGNIFICANCE
Type A loading may provide a predictable and time-efficient alternative to conventional delayed loading without compromising clinical outcomes.
Mohammed A. Elsawy, Mohammed T. Khater, Islam Kandil et al.· E -journal of dentistry· 0 citations
BACKGROUND
This study aimed to describe changes in marginal bone levels (MBL) and peri-implant trabecular radiomorphometric patterns during the osseointegration period in posterior mandibular implants healed with either healing abutments or cover screws.
METHODS
This retrospective radiographic cohort study included 53 posterior mandibular implants in 36 patients, classified into the healing abutment group (n = 22) and the cover screw group (n = 31), based on the immediate postoperative panoramic radiographs. Digital panoramic radiographs obtained before implant placement (T0), immediately after implant placement (T1), and after a 3-month osseointegration period (T2) were analyzed. Marginal bone level (MBL) changes and radiomorphometric indices, including fractal dimension (FD), lacunarity, bone area fraction (BAF), and mean gray value (MGV), were calculated.
RESULTS
MBL values decreased significantly from T1 to T2 in both groups (p < 0.05). No statistically significant between-group difference in MBL change was detected at either the mesial or distal surface (p > 0.05). In the overall cohort, mean lacunarity decreased, whereas mean FD, BAF, and MGV increased. Group-based analyses showed significant longitudinal changes in all radiomorphometric parameters in the cover screw group, while only FD changed significantly in the healing abutment group (p < 0.05). For the overall mean radiomorphometric values, no statistically significant between-group differences were detected at T2 (p > 0.05).
CONCLUSIONS
Posterior mandibular implants showed MBL reductions and radiomorphometric changes during the 3-month osseointegration period. MBL changes did not differ significantly between groups, while radiomorphometric trajectories differed descriptively. These findings provide descriptive radiographic information on early peri-implant bone changes and should be interpreted within the limitations of the retrospective cohort design.
