The ability to screw-retain single implant-supported restorations in the anterior maxilla: A CBCT analysis.

STATEMENT OF PROBLEM: Evidence to validate the routine use of angled screw-channel abutments in the anterior maxilla is sparse. If properly planned, they might provide surgical and prosthetic benefits. PURPOSE: The purpose of this observational study was to determine the prevalence of digitally placed implants in the anterior maxilla that would allow screw-retained implant-supported restorations with either a straight or an angled screw-channel abutment. MATERIAL AND METHODS: Two hundred cone beam computed tomography (CBCT) scans met the inclusion criteria for retrospective analysis and digital implant planning. Virtual implants were planned for randomly selected anterior maxillary teeth by using the anatomic crown and root position. Virtual abutments of varying angulation were attached to the implants to determine the ability to screw retain a restoration with either a straight or an angled screw-channel abutment. RESULTS: One hundred fifty-two (76%) sites required an angled screw-channel abutment to enable screw retention. Forty-eight (24%) sites allowed screw retention with a straight abutment. The percentage of implants requiring angled or straight abutments varied significantly among anterior teeth (P<.005). One hundred nine (71.7%) angled screw-channel abutment sites required a 5-degree abutment, 41 (26.9%) required a 10-degree abutment, and 2 (1.3%) required a 15-degree abutment. Among the anterior teeth, lateral incisors presented a greater need for angled screw-channel abutments. None of the implants in the present study needed cement-retained restorations. CONCLUSIONS: Angled abutments allowed for screw-retained restorations on digitally planned implants in the anterior maxilla. The required angular correction to a screw-retained restoration was ≤15 degrees. Screw-retained restorations were frequently achievable (76%) with the use of angled screw-channel abutments or with straight abutments (24%), and lateral incisors presented a greater need for angled screw-channel abutments.

The effect of low-level diode laser on COX-2 gene expression in chronic periodontitis patients.

Adjunctive treatments to scaling and root planing (SRP) such as lasers, have been utilized in the treatment of chronic periodontitis, mainly aiming to suppress and eliminate the bacteria, as well as enhancing the healing response. Eighty gingival papilla biopsy samples were obtained from 60 patients diagnosed with chronic advanced periodontitis; randomly assigned to three treatment groups (n = 20), as well as 20 subjects with no periodontal disease [group A]. Group B received SRP on a single quadrant/day for four consecutive days. On day 5, all quadrants were rescaled. Groups C and D received the same treatment as group B plus laser application with the low-level diode laser (630-670 nm, 1.875 J/cm2) for five and ten consecutive days, respectively. Papilla biopsies were obtained from subjects and evaluated by RT-PCR for expression of COX-2. The values in the control group were 0.028 0.014 and baseline values for the examined groups were 0.16 0.18. Significantly decreased level of COX-2 expression for groups C and D was found after treatment, while lowest average expression was found in the group that had the 10 laser treatments supplemental to SRP (0,035 0,014). The results of this study show suppression of COX-2 in gingival tissue after low-level laser treatment as adjunct to SRP.

Temperature Changes (ΔT) in Correlation with Number of Implant Osteotomy Preparations in Human Cadaver Tibiae, Comparing Osseodensification (OD) Burs in Clockwise (CW) versus Counterclockwise (CCW) Mode.

(1) Background: OD burs are used in two different modes: (i) CW and (ii) CCW. The purpose of the study was to evaluate the ΔT during the preparation of implant osteotomies in a four-way interaction. (2) Methods: Three hundred and sixty osteotomies were prepared at 12 mm depth in human cadaver tibiae. The ΔT values were calculated similarly to the method used in two previous studies carried out by our group. Four different variables were evaluated for their effect on ΔT. (3) Results: A four-way interaction was observed in the CCW mode, allowing for 1000 RPM to have the least effect in both modes. However, in the CCW mode the use of 3.0 and 4.0 burs after 23 osteotomies showed a statistically significant increase in ΔT, and significant chatter, compared to the CW mode. In the CCW mode, the ΔT was increased significantly as the diameter of the burs increased in 800 and 1200 RPM. (4) Conclusions: The synergistic effect of drills' diameter, CCW mode, 800 and 1200 RPM, and bur usage (over 23 times) had a significant effect on ΔT, which exceeded 47 °C. One thousand (1000) RPM had the least effect in both modes. The 3.0 and 4.0 burs in the CCW mode drastically increased the temperature and produced significant chatter.

A retrospective analysis of the role of age and sex in outcomes of non-surgical periodontal therapy at a single academic dental center.

The present study examined the role of age and sex in the outcomes of non-surgical periodontal therapy (NSPT). De-identified demographic and periodontal characteristics of patients who presented for baseline periodontal evaluation, NSPT, and periodontal re-evaluation were abstracted from electronic health records. Independent associations of age and sex with severe periodontitis defined as ≥ 5 mm clinical attachment loss (CAL) and ≥ 6 mm probing depth (PD) were determined using multinomial logistic regression. The null hypothesis was rejected at α < 0.05. A total of 2866 eligible subjects were included in the analysis. Significantly lower odds of CAL ≤ 4 mm than CAL ≥ 5 mm (reference) were observed in adults aged 35-64 (odds ratio, OR, 0.19; 95% confidence interval, CI 0.13, 0.29) and ≥ 65 years (OR 0.13; 95% CI 0.07, 0.25) compared to those aged 18-34 years. Odds of PD < 4 mm versus PD ≥ 6 mm (reference) were lower in adults aged 35-64 years than those aged 18-34 years (OR 0.71; 95% CI 0.55, 0.90) and higher in females compared to males (OR 1.67; 95% CI 1.14, 2.44). These results suggest more compromised post-NSPT outcomes in older adults and males compared to the respective populations and highlight the need for personalized therapeutic strategies in these populations.

The Significance of Mylohyoid Muscle Release (MMR) in the Vertical and Horizontal Ridge Augmentation Surgeries; Clinical and Human Cadaver Analyses of the Techniques.

(1) Background: Ridge augmentations either horizontal (HRA) or vertical (VRA) in the posterior mandible are very challenging regenerative procedures. To attain and retain tension-free primary closure, buccal periosteal and mylohyoid muscle releases should be performed. The purpose of the present study was to review, analyze and discuss the three different techniques for the mylohyoid muscle release (MMR) in VRA and HRA surgeries on a clinical and human cadaver level. (2) Presentation of the techniques: Three different techniques are described in the literature regarding the lingual flap management: (i) the finger sweep technique (FST), (ii) the release of the mylohyoid muscle attachment on the lingual flap (MMALF), and (iii) the mylohyoid preservation technique (MPT) in three key anatomical zones. All three techniques, even though they use a different approach, can achieve similar amount of horizontal and vertical mylohyoid muscle release although MPT showed statistically significant higher flap advancement. The human cadaver analyses revealed that all three techniques are considered safe since they do not approximate vital anatomical structures. (3) Conclusions: All three techniques are considered safe, but they are not free of limitations or complications; therefore, they should be performed only by highly experienced and trained clinicians. MPT achieved statistically significant higher flap advancement.

Vertical Ridge Augmentation Around Dental Implants With the Use of a Dense PTFE Membrane to Correct Previously Failed Augmentations.

INTRODUCTION: Vertical ridge augmentation (VRA) is one of the most challenging procedures. This is the first case report to show 2-5 mm VRA after two unsuccessful GBRs around previously placed dental implants, with the use of an exposed d-PTFE membrane. CASE PRESENTATION: A 79-year-old ASA II Caucasian male presented after two previous GBR procedures on the LLQ. The second attempt left the site with two exposed implants, scar tissue, no keratinized tissue and lack of vestibular depth. VRA was attempted with the use of cortical perforations, tenting screws, dense PTFE membrane and a 50:50 mixture of anorganic bovine bone matrix and mineralized allograft. The site was left to heal in a secondary intention, leaving the d-PTFE membrane exposed. The membrane was removed 4 weeks postoperatively. The healing abutments were placed, the tenting screws were removed, and the site was allowed to heal for more than seven months. Radiographically, VRA was achieved ranging from 2 to 5 mm. A vestibuloplasty was performed using a diode laser and subsequent flap dissection. Four months after the vestibuloplasty, the tissue surrounding the implants showed adequate keratinization, and an elongated vestibular depth. In addition, in both implants, the emergence profile buccal and lingual was more than 3 mm and the patient was referred to his prosthodontist for the fabrication of the final restorations. CONCLUSIONS: VRA around dental implants was achieved with the use of a nonresorbable dense PTFE membrane, which was left exposed to heal in a secondary intention, tenting screws and a combination grafting technique to correct two previously failed GBRs.

The Surgical Anatomy of the Greater Palatine Artery: A Human Cadaver Study.

Identifying the accurate location of the greater palatine artery (GPA) can be challenging. The purpose of the present cadaver study was to determine the location of the GPA from the cementoenamel junction (CEJ) of the maxillary canine to second molar teeth and to define its relationship with the palatal vault height (PVH) in Caucasian cadavers. Sixty-six sections from fully or partially dentate cadavers were examined. The location of the GPA from the CEJ ranged from a minimum of 8.7 ± 2.1 mm at the canine to 14.5 ± 1.3 mm at the second molar. The minimum distance of the GPA to the CEJ in different PVH ranged from 6 to 12 mm. There was a significant difference between male and female cadavers regarding shallow PVH. Only the PVH as an independent variable had a significant correlation with the GPA location. The present study is the first to identify the different PVHs with customized stents and to correlate them with the distance of the GPA to the CEJ of maxillary teeth.

Temperature Changes during Implant Osteotomy Preparations in Human Cadaver Tibiae Comparing MIS® Straight Drills with Densah® Burs.

(1) Background: Several studies showed a sustained temperature of 47 °C or 50 °C for one minute resulted in vascular stasis and bone resorption with only limited bone regrowth over a 3-4-week healing period. The purpose of the present study was to evaluate the temperature changes (ΔΤ) that occur during the preparation of dental implant osteotomies using MIS® straight drills versus Densah® burs in a clockwise (cutting) drilling protocol. (2) Methods: Two hundred forty (240) osteotomies of two different systems' drills were prepared at 6 mm depth at 800, 1000, and 1200 revolutions per minute (RPM), in fresh, unembalmed tibiae, obtained by a female cadaver. ΔΤ was calculated by subtracting the baseline temperature on the tibial surface, from the maximum temperature-inside the osteotomy (ΔT = Tmax - Tbase). The variables were evaluated both for their individual and for their synergistic effect on ΔΤ with the use of one-, two-, three- and four-way interactions; (3) Results: An independent and a three-way interaction (drill design, drill width, and RPM) was found in all three RPM for the Densah® burs and at 1000 RPM for the MIS® straight drills. As Densah® burs diameter increased, ΔΤ decreased. The aforementioned pattern was seen only at 1000 RPM for the MIS® straight drills. The usage of drills 20 times more than the implant manufacturers' recommendation did not significantly affect the ΔΤ. A stereoscopic examination of the specimens confirmed the findings. (4) Conclusions: The independent and synergistic effect of drills' diameter, design and RPM had a significant effect on ΔΤ in human tibiae, which never exceeded the critical threshold of 47 °C.

Temperature Changes during Implant Osteotomy Preparations in Fresh Human Cadaver Tibiae, Comparing Straight with Tapered Drills.

The success of osseointegration depends on many factors. With temperatures beyond a 47 °C threshold over 1 min, bone survival may be impaired. The purpose of the study was to evaluate, in fresh human cadaver tibiae, the temperature changes during osteotomy preparations using two straight and two tapered implant systems' drills, external irrigation, and varying revolutions per minute (RPM). The tibiae from a fresh female cadaver were harvested bilaterally. Two tapered and two straight design drills were assessed. Two-hundred and forty osteotomies were prepared at 6 mm depth following the drill sequence of the manufacturers' protocol for each drilling speed. Difference in temperature (ΔΤ) was calculated by subtracting the baseline from the maximum temperature (ΔT = Tmax - Tbase). Drill design and drill diameter, as independent variables or synergistically, had a significant effect on ΔΤ. Tapered drills: As the drill diameter increased, ΔΤ increased at all RPM. Straight drills: As the drill diameter increased, ΔΤ remained constant or slightly decreased at all RPM. Drill diameter and design had a significant effect on ΔΤ in human tibiae, which never exceeded the critical threshold of 47 °C. Tapered drills caused significantly greater heat production compared to straight drills.

Vertical ridge augmentation (VRA) with the use of a cross-linked resorbable membrane, tenting screws, and a combination grafting technique: a report of three cases.

OBJECTIVE: The purpose of the present study was to present vertical ridge augmentation (VRA) with the use of cross-linked resorbable membrane, tenting screws, and a combination grafting technique. REPORT: Three cases are presented. Case 1: A 67-year-old ASA II patient required VRA at the areas of the mandibular left second premolar and first molar. Flap management was performed with the use of periosteal release on the buccal aspect and 23 mm of mylohyoid muscle release on the lingual aspect. VRA was completed with the use of four self-tapping tenting screws, and 1:1 mix of anorganic bovine bone matrix (ABBM) and particulate mineralized bone allograft. A cross-linked resorbable membrane was placed over the buccal and lingual aspect, and a double line of suturing was performed to secure the tension-free closure. Twelve months postoperatively, 4 mm of VRA was confirmed with CBCT. Two implants were placed with >35 Ncm primary stability. Case 2: A 64-year-old ASA I patient required VRA at the area of the maxillary first premolar. Flap management was performed with the use of periosteal release on the buccal aspect and VRA was performed with a 9-mm self-tapping screw, 1:1 mix of ABBM and particulate mineralized bone allograft, a cross-linked resorbable membrane, and a double line of suturing. Twelve months postoperatively, VRA of 6.2 mm on the buccal aspect and 7.9 mm on the lingual aspect were confirmed with CBCT. An implant was placed with > 35 Ncm primary stability in combination with horizontal ridge augmentation. Case 3: A 70-year-old ASA II patient required horizontal and VRA at the area of the mandibular left canine. Following extraction, a lateral pedicle sliding flap was completed to enhance the soft tissue volume of the site. After 6 weeks, flap management was performed with the use of buccal periosteal release, VRA was completed with two self-tapping screws, 1:1 mix of ABBM and particulate mineralized bone allograft, a cross-linked resorbable membrane, and a double line of suturing. Eight months postoperatively there was 5.3 mm of bone regeneration on the vertical dimension and 3.9 mm on the horizontal dimension. An implant was placed with primary stability of 45 Ncm. CONCLUSION: Successful VRA can be achieved with proper flap management to achieve tension-free closure, a cross-linked collagen membrane, tenting screws, and a combination grafting technique. The VRA ranged from 4.0 to 7.9 mm.

Evaluation of the need to prescribe opioid medication to control post-surgical pain of different periodontal/oral surgeries.

BACKGROUND: To determine the level of perceived pain after different types of periodontal/oral surgical procedures, and the differences in patients' selection of pain management, over the counter (OTC) versus opioid, based on procedure type. METHODS: Patients undergoing surgical procedures were asked to complete a pain questionnaire at four time points: 1) before surgery 2) first dose of analgesic at home, 3) 24 hours postoperatively, and 4) 72 hours postoperatively. The questionnaire consisted of numerical and descriptive scales to describe the perceived pain. RESULTS: A total of 198 patients completed the questionnaire. All surgical procedures were grouped into five major categories: bone augmentation procedures (11% BAP), teeth extractions (26% EXT), surgical implant placement (25% IP), mucogingival surgeries (21% MGS), and pocket elimination procedures (17%). IP surgery was associated with significantly less pain compared with MGS and EXT (P <0.05). There was a statistically significant difference for taking any medication based on type of surgical procedure at 24 hours (P <0.05). CONCLUSIONS: IP is associated with significantly lower perceived pain compared with EXT and MGS surgery. Analgesic consumption was generally parallel to pain perception. A considerable number of patients elected to control the post-surgical pain using OTC medication up to 72 hours. Periodontal/oral surgery procedures vary in the amount of perceived postoperative pain. Tailoring postoperative medications to the type of periodontal/oral surgery performed will help prevent overprescribing of opioids.

Mandibular implant-retained overdenture relining procedure with an attachment system: A step-by-step demonstration of the technique.

BACKGROUND AND OVERVIEW: Because of continuous alveolar bone resorption, implant-retained overdentures need to be relined. The purpose of this study was to describe a method for relining an implant-retained overdenture. CASE DESCRIPTION: The authors present a step-by-step technique. A 65-year-old patient sought care for trauma and pain in the oral mucosa underneath his mandibular implant-retained overdenture. The overdenture had been fabricated 4 years previously. In addition, the patient mentioned the denture's lack of stability during function. On the basis of the patient's dental history, and clinical and radiographic examination results, the authors found alveolar bone resorption. CONCLUSIONS AND PRACTICAL IMPLICATIONS: In this case report, the authors describe the technique, analyze the procedure of implant-retained overdenture relining with a Locator attachment system (Locator abutment, H3, SP MB SZL03 for internal hex implants; MIS Seven), and describe how to restore the contact of the denture base with the denture-bearing tissues. The goal of this technique for the general dentist is to eliminate patients' tissue trauma and pain and increase the stability and support of the prosthesis.

Survival of Dental Implants Replacing Previously Failed Implants: A Retrospective Study in a University Setting.

PURPOSE: The rate of dental implant failures ranges from 3% to 8%, with that number increasing as the number of implants placed increases. When an implant fails, the survival rate drops significantly when a second or third attempt is performed. The aim of this study was to evaluate the survival rate of an implant placed in a previously failed implant site and to explore the risk factors that might affect the outcome of the second procedure. MATERIALS AND METHODS: A retrospective chart review was conducted for patients receiving dental implants at the University of Texas, School of Dentistry from 1985 to 2017. Exclusion criteria included patients with genetic diseases, radiation and chemotherapy, or an age less than 18 years. Data on age, sex, race, tobacco use, diabetes, cardiovascular, osteoporosis, implant brand, anatomical location of the implant, implant length and width, respective information on the replacement implant, and professional maintenance were collected for analysis. RESULTS: A total of 1,234 patients with 2,742 implants were included. A chart review found that of the 247 failed implants, replacement of implants was performed in 85 patients with 99 implants. More than half of the initial implants failed within the first year of placement. Based on the 12-month performance of each brand, the initially failed implants were categorized as high, medium, or low survival rates. Based on this categorization, the replacement implants that belonged to the medium survival rate category showed higher survival rates than the high survival group of the initially failed implants. CONCLUSION: The cumulative survival rates of the replacement implants were 91% at 1 year, 88% at 5 years, and 83% at 10 years. Implant failures were more common prior to functional loading.

Management of Retrograde Peri-Implantitis Using an Air-Abrasive Device, Er,Cr:YSGG Laser, and Guided Bone Regeneration.

BACKGROUND: The placement of an implant in a previously infected site is an important etiologic factor contributing to implant failure. The aim of this case report is to present the management of retrograde peri-implantitis (RPI) in a first maxillary molar site, 2 years after the implant placement. The RPI was treated using an air-abrasive device, Er,Cr:YSGG laser, and guided bone regeneration (GBR). CASE DESCRIPTION: A 65-year-old Caucasian male presented with a draining fistula associated with an implant at tooth #3. Tooth #3 revealed periapical radiolucency two years before the implant placement. Tooth #3 was extracted, and a ridge preservation procedure was performed followed by implant rehabilitation. A periapical radiograph (PA) showed lack of bone density around the implant apex. The site was decontaminated with an air-abrasive device and Er,Cr:YSGG laser, and GBR was performed. The patient was seen every two weeks until suture removal, followed by monthly visits for 12 months. The periapical X-rays, from 6 to 13 months postoperatively, showed increased bone density around the implant apex, with no signs of residual clinical or radiographic pathology and probing depths ≤4 mm. CONCLUSIONS: The etiology of RPI in this case was the placement of an implant in a previously infected site. The use of an air-abrasive device, Er,Cr:YSGG, and GBR was utilized to treat this case of RPI. The site was monitored for 13 months, and increased radiographic bone density was noted.

Ridge Preservation Procedures after Tooth Extractions: A Systematic Review.

BACKGROUND: The purpose of this systematic review was to accurately assess the procedural success of ridge preservation technique through the application of strict inclusion and exclusion criteria. DATA SOURCES: A methodical search of PubMed of the US National Library of Medicine and the Cochrane Central Register of Controlled Trials was conducted for applicable articles. Only randomized controlled trials comparing ridge preservation treatment with a nongrafting control, ten-subject minimum sample size, and three or more months of follow-up were included in our study. TYPES OF STUDIES REVIEWED: In a screening between January 1980 and September 2017, articles meeting predetermined criteria were further examined in a qualitative data analysis. A thorough search of the databases provided 1876 articles. Of these records, 174 were assessed for eligibility through the systematic employment of inclusion and exclusion criteria. RESULTS: Two records were appropriate for further data analysis. One study used a mixture of a deproteinized cancellous bovine bone and porcine collagen fibers in a block form (DBB/CF), while the other study used leukocyte-platelet-rich fibrin (L-PRF). The use of DBB/CF reduced the magnitude of vertical bone resorption, yet the study showed high risk of bias. The use of L-PRF reduced the magnitude of both the horizontal and vertical crestal bone resorption; however, the low sample size created wide standard deviations between the test and control groups. Inherent weaknesses were present in both studies. Through methodical analysis of both records, the dissimilarities prevented the conduction of a meta-analysis. IMPLICATIONS OF KEY FINDINGS: Within the limitations of this systematic review, L-PRF reduced the magnitude of vertical and horizontal bone resorption, which places L-PRF as a potential material of choice for ridge preservation procedures. CONCLUSIONS: Within the limitations and weaknesses of both studies, the use of DBB/CF prevented the vertical crestal bone resorption while the L-PRF prevented both the horizontal and vertical crestal bone resorption. More randomized controlled clinical trials are needed to eliminate all the confounding factors, which bias the outcome of ridge preservation techniques.

Limitations and options using resorbable versus nonresorbable membranes for successful guided bone regeneration.

OBJECTIVE: Deficient bony ridges often complicate the implant treatment plan. Several treatment modalities are used to regenerate bone, including guided bone regeneration (GBR). The purpose of this study was to summarize the knowledge on different types of membranes available and currently used in GBR procedures in a staged approach or with simultaneous implant placement. The primary role of the membranes is to exclude epithelial and connective tissue cells from the wound area to be regenerated, and to create and maintain the space into which pluripotential and osteogenic cells are free to migrate. DATA SOURCES: A literature search was performed for articles that were published in English on the topic. A selected number of studies were chosen in order to provide a review of the main characteristics, applications, and outcomes of the different types of membranes. Resorbable membranes are made of natural or synthetic polymers like collagen and aliphatic polyesters. Collagens are the most common type used. They have similar collagen composition to the periodontal connective tissue. Other materials available include human, porcine, and bovine pericardium membranes, human amnion and chorion tissue, and human acellular freeze-dried dermal matrix. Nonresorbable membranes used in GBR include dense-polytetrafluoroethylene (d-PTFE), expanded-polytetrafluoroethylene (e-PTFE), titanium mesh, and titanium-reinforced polytetrafluoroethylene. CONCLUSIONS: The most common complication of nonresorbable membranes is exposure, which has detrimental effect on the final outcome with both types of membranes. For vertical bone augmentation procedures, the most appropriate membranes are the nonresorbable. For combination defects, both types result in a successful outcome.

A Novel Treatment Decision Tree and Literature Review of Retrograde Peri-Implantitis.

BACKGROUND: Although retrograde peri-implantitis (RPI) is not a common sequela of dental implant surgery, its prevalence has been reported in the literature to be 0.26%. Incidence of RPI is reported to increase to 7.8% when teeth adjacent to the implant site have a previous history of root canal therapy, and it is correlated with distance between implant and adjacent tooth and/or with time from endodontic treatment of adjacent tooth to implant placement. Minimum 2 mm space between implant and adjacent tooth is needed to decrease incidence of apical RPI, with minimum 4 weeks between completion of endodontic treatment and actual implant placement. The purpose of this study is to compile all available treatment modalities and to provide a decision tree as a general guide for clinicians to aid in diagnosis and treatment of RPI. METHODS: Literature search was performed for articles published in English on the topic of RPI. Articles selected were case reports with study populations ranging from 1 to 32 patients. Any case report or clinical trial that attempted to treat or rescue an implant diagnosed with RPI was included. RESULTS: Predominant diagnostic presentation of a lesion was presence of sinus tract at buccal or facial abscess of apical portion of implant, and subsequent periapical radiographs taken demonstrated a radiolucent lesion. On the basis of case reports analyzed, RPI was diagnosed between 1 week and 4 years after implant placement. Twelve of 20 studies reported that RPI lesions were diagnosed within 6 months after implant placement. A step-by-step decision tree is provided to allow clinicians to triage and properly manage cases of RPI on the basis of recommendations and successful treatments provided in analyzed case reports. It is divided between symptomatic and asymptomatic implants and adjacent teeth with vital and necrotic pulps. CONCLUSIONS: Most common etiology of apical RPI is endodontic infection from neighboring teeth, which was diagnosed within 6 months after implant placement. Most common findings, radiographically and clinically, are lesions around implant apex and sinus tract. A small number of implants did not improve with treatment. Decision tree provides a path to diagnose and treat lesions to facilitate their management. Further studies are needed to focus on histologic data around periapical microbiota to establish specific etiology and differential diagnoses compared with marginal peri-implantitis and other implant-related conditions.