Patient-centered outcome measures comparing the autogenous and allogenic bone blocks in the augmentation of deficient alveolar ridges: A pilot study

Abstract

Background:

The aim of the present study was to evaluate and compare the patient-reported experience and outcome measures (PREMS and PROMS) and three-dimensional augmentation efficacy of the autogenous and allogenic bone block grafts in deficient alveolar ridges through cone beam computed tomography (CBCT).

Materials and Methods:

Twenty patients were equally divided into Groups I and II treated with autogenous and allogenic bone block grafts for ridge augmentation, respectively. The radiographic parameters including the apico-coronal defect height (DH) as well as buccolingual defect depth (DD) and mesiodistal defect width (DW) at apical, middle, and cervical zone were measured using CBCT at baseline, 6 months and 1 year. The PREMS and PROMS were evaluated using Visual analogue scale (VAS) scale and questionnaire method.

Results:

The mean DH, apical DD and DW, middle and cervical zone DW were significantly different between two study groups (P < 0.05). The mean apical 11.6 ± 1.91 and middle zone 9.43 ± 0.89 DD were significantly higher (in Group I as compared to Group II, with P values 0.016 and 0.004, respectively). The mean bone gains in apico-coronal DH and mesio-distal DW dimension in the apical and middle zone was significantly higher in Group I (P < 0.0001). The comparison of PROM revealed better patient satisfaction in Group II as depicted by significantly higher VAS score (P < 0.0001).

Conclusion:

Superior bone gain and reduced graft resorption was observed in Group I when compared to Group II. On the contrary, better PROMs and PREMs were obtained with the allogenic bone block augmentation.

INTRODUCTION

Patient-reported experience measures (PREMs) are indications of a patient’s impression of qualitative components of their health-care experience. These are elements that patients either directly or indirectly notice throughout their therapy. Alongside, patient-reported outcome measures (PROMs) are the objective assessments of a patient’s understanding of their health state and associated quality of life which offer data on clinical outcomes related to a certain treatment method.[1] Darzi[2] claimed that PREMs and PROMs are two of the greatest measures of quality which is essential to be evaluated on a routine basis but unfortunately ignored by clinicians. The use of PROMs in general medicine has attaining importance in the recent times and is emerging method to assess various treatment modalities, leading to a paradigm shift to “patient- centered care.”[3,4]

The use of dental implant has become a standard treatment in many clinical situations however, in order to achieve optimal functional and esthetic results the clinician has to assess the complexity and risks associated with the implant therapy before starting the treatment. Patients frequently present with ridge atrophy, which might obstruct the implant placement in prosthetically correct position. The clinicians must be aware of postextraction dimensional changes of the alveolar ridge since the quantity and quality of bone is a critical predictor of implant success. Vertical bone resorption is dependent on the phenotype of the buccal bone wall; it is greater and extensive in amount in patients with thin-walled phenotypes than in thick-walled phenotypes.[5–7] Insufficient bone at the site of implant placement has been attempted to be restored with augmentation techniques with different graft materials including particulate as well as bone blocks.

Guided bone regeneration enables the clinician to accomplish reconstruction of deficient sites for a successful dental implant installation. The most widely used bone graft material for such reconstruction is autogenous bone, which is currently considered the gold standard due to its osteoconductivity, osteoinductivity, and osteogenecity.[8,9] Symphyseal region offers a large amount of cortico-cancellous autograft and easy access for procurement among all the intraoral sites. Convenient surgical access, low morbidity, elimination of hospital stay, minimal donor site discomfort, and avoidance of cutaneous scars are the added advantages of this treatment modality. Often-quoted disadvantages of harvesting bone from the intraoral donor sites are the need for a secondary surgical site, risk of vascular and neurologic injury, and postoperative morbidity. The reluctance of patients to undergo an additional surgical procedure is also cited by some of the clinicians as a major drawback to such procurement.

On the other hand, allografts appear to be a reasonable alternative of bone graft material that may be used to avoid most of the aforementioned disadvantages. Additional advantages include a ready availability of large volumes of material, extremely low antigenic potential, decreased operative trauma and blood loss, absence of donor site morbidity, and osteo-conductivity along with the possession of bone-inductive/morphogenetic proteins (BMP).

Previous studies[10–12] have reported high clinical performance of processed de-cellularized block allografts for alveolar ridge augmentation. Although these studies provide a considerable amount of data on the effectiveness of allogeneic bone blocks, patient groups and the quality of evidence in most individual publications are poor, leaving an urgent need for greater verification of this information.[13] As mineralized bone allograft represents the only grafting material which has been demonstrated to function analogous to traditional autogenous block grafting by multiple authors, comparative studies on their clinical performance in horizontal and vertical bone augmentation are of high scientific relevance.[14–16]

Furthermore, there is a paucity of literature evaluating PREMs and PROMs comparing the autogenous bone block and allogenic bone blocks in the augmentation of maxillary edentulous alveolar ridges. Consequently, the aim of this clinical study was to compare patient-centred outcome measures and efficacy of autogenous and allogenic bone blocks in the augmentation of deficient alveolar ridges for the placement of dental implants.

MATERIALS AND METHODS

The present pilot study was conducted from January 2020 to June 2021 at the outpatient Department of Periodontology, of our institute in accordance with the Helsinki Declaration of 1975, as revised in 2013 and was registered at Clinical Trial Registry of India. A written informed consent was obtained from all the participating patients. The study was also approved by Institutional Ethics Committee.

A total of 20 patients in the age range of 20–50 years were enrolled for the study and were fully informed about the surgical procedure and treatment alternatives. Patients were randomly divided into two groups using simple randomization method by computer-generated numbers to reduce potential bias involved.

• Group I – Patients treated using autogenous bone block graft (n = 10)

• Group II –Patients treated using allogenic DFDBA bone block graft (n = 10).

The inclusion criterion mandated systemically healthy patients requiring dental implant placement, presence of a clinically relevant bone atrophy of the alveolar ridge in the predominantly horizontal and/or vertical plane as identified by cone beam computed tomography (CBCT). The minimum defect size of ≤3 mm at crestal and middle sites of bucco-palatal dimension of residual alveolar ridge, edentulous space of a single tooth missing in the maxillary anterior region were included. The exclusion criteria consisted of a history of radiotherapy in the head and neck region, existing severe periodontal disease, bruxism, smoking habit or alcoholism, pregnancy, psychiatric problems, and/or use of medications known to alter bone healing.

After screening, radiographic examination including CBCT analysis was carried out before undergoing the surgical procedure. The patients underwent a thorough initial periodontal examination including the plaque index, gingival index, and probing depth. The preoperative CBCT measurements are as follows:

The alveolar bone levels were measured in their height, width, and depth at the cervical, middle, and apical level taking adjacent teeth as reference [Figure 1].

Figure 1.

(a) CBCT image showing Preoperative defect depth at Cervical (CDD), Middle (MDD) and apical level (ADD); (b) CBCT image showing Post-operative defect depth augmentation site after 6 months at CDD, MDD and ADD levels; (c) CBCT image showing Post-operative defect width augmentation site after 6 months at Cervical (CDW), Middle (MDW) and apical (ADW) level after 6 months. CBCT – Cone beam computed tomography

Defect height

Apico-coronal distance between the crestal and apical bone level in the middle of the defect region.

Defect width

Mesio-distal distance between the neighboring teeth at the apical (ADW), middle (MDW). and cervical level (CDW).

Defect depth

Buccolingual distance between the labial/buccal and palatal edges of the edentulous ridge at the apical (ADD), middle (MDD), and cervical (CDD) level of the root of the neighboring mesial tooth.

The postoperative CBCT analysis was performed after 12 months for radiographic assessment of the bone augmentation. Readings were repeated by the same examiner (PB) to perform intra-observer reproducibility analysis.

The symphysis graft was harvested using the surgical technique (rule of 5’s) proposed by Misch et al.[17] A full-thickness mucoperiosteal flap was raised by crestal incision up to the inferior border to expose the symphysis. The superior osteotomy cut was placed at least 5 mm inferior to the apex of the mandibular teeth and the inferior cut was placed approximately 5 mm superior to the inferior border of the mandible and a safe distance of 5 mm was maintained from mental foramen.

Micro osteo-perforations were incorporated at the recipient site to initiate the regional acceleratory phenomenon. A cortico-cancellous bone block was harvested and screwed at the required site using osteosynthesis titanium screws (Ortho Max, Gujarat, India). Both the donor and recipient sites were sutured to obtained tension free primary closure with some cases requiring coronal advancement of the soft tissue.

The cortico-cancellous allogeneic blocks (DFDBA) were obtained from the tissue bank (TATA Memorial Hospital, Mumbai, Maharashtra, India). Full-thickness mucoperiosteal flap was raised and micro osteoperforations were performed at the recipient site after which the onlay grafts were adapted to the defect site and fixed onto the ridge with osteosynthesis screws and sutured. In both the groups, the defect was covered with a bioresorbable chorion membrane (Tata Memorial Hospital Tissue Bank, Mumbai, Maharashtra, India) to avoid the epithelial cells migration into the defect [Figure 2].

Figure 2.

(a) Intra-oral Preoperative clinical photograph showing the ridge defect; (b) Intra-operative Block graft fixation; (c) Follow up after 6 months (d) Implant placed at the augmented site

PREMs and PROMs were evaluated using a questionnaire and Visual Analog Scale[18] immediately after each procedure in both the groups. The responses were recorded on the Likert scale. The completed questionnaires and contact details of each patient were stored securely in a box only accessible to the authors at all times. For each surgical technique the following domains were used to evaluate the VAS Score (a) opinion on treatment length (1 = unsatisfactory to 10 = excellent), (b) comfort level during procedures (1 = unsatisfactory to 10 = excellent), (c) anxiety level before procedures (1 = high to 10 = low), (d) unpleasant experience during/after procedures (1 = worst to 10 = none), and (e) pain during procedures (1 = painful to 10 = none). The PREMs questionnaire [Figure 1] consisted of five questions while the PROMs [Figure 2] consisted of ten questions related to outcome measures.

After 6 months, a second CBCT scan was taken to assess the amount of bone augmentation achieved for the placement of implant of appropriate diameter followed by subsequent implantation.

The DD and DW parameters were summarized in terms of mean and standard deviation. The comparison of means of different parameters between two groups was performed using t-test for independent samples. This analysis was performed at all the three time points. Further, the within group comparison for each parameter across times was performed using repeated measure analysis of variance. The pair wise comparison of each parameter between two time points was performed and P values were adjusted using Bonferroni multiple testing correction method. The mean bone gain and graft resorption corresponding to each parameter were compared between the two groups using t-test for independent samples. Furthermore, the proportion of cases with graft exposure was determined at each time point in the groups. Comparison of the mean VAS score of patients was obtained using Mann–Whitney U-test while the comparison of PREM and PROM responses was obtained using the Chi-square test. All the analyses were performed using the SPSS software ver. 26 (IBM Corp., Armonk, New York, USA) software and the statistical significance was tested at 5% level.

RESULTS

Table 1 provides the comparison of various parameters between the two groups at three time points. At baseline, the mean DH, ADD, ADW, MDW, and CDW were significantly different between the two study groups (P < 0.05). The apico-coronal DH was significantly smaller in Group I as compared to Group II, while other parameters were significantly higher in Group I as compared to Group II. At 6 months, apico-coronal DH continued to be significantly different between two groups (P < 0.0001); however, the mean in Group I was significantly higher than that of Group II. The mean ADD and MDD were significantly higher in Group I as compared to Group II, with P values 0.016 and 0.002 respectively. These three parameters differed significantly even at 1 year, with higher means in Group I as compared to Group II. Table 2 shows within group comparison of parameters across time. In Group I, the parameters DH, ADD, MDD, and CDD showed statistically significant increase with time (P < 0.0001). The pair wise comparison between times for each parameter revealed that the mean difference of apico-coronal DH and mean difference of various defect depths (DD) between baseline and 6 months were significantly different than zero. Later, the mean difference between 6 months and 1 year was insignificantly different than zero (P > 0.05). The mean ADW, MDW, and CDW showed statistically significant decrease with time (p < 0.0001). The pair wise analysis revealed that for all the three defect widths (DW), the mean difference between baseline and 6 months was statistically significant; however, subsequently, the mean difference between 6 months and 1 year was insignificantly different than zero.

Table 1.

Comparison of various parameters between two groups at three time points

Time	Parameter	Mean±SD (mm)		P*
		Group I	Group II
Baseline	DH (apical - coronal)	6.79±0.56	7.55±0.83	0.028
	ADD (bucco - lingual)	7.53±0.68	5.56±0.85	<0.0001
	MDD (bucco - lingual)	4.17±0.75	4.53±0.76	0.299
	CDD (bucco - lingual)	3.25±0.68	3.15±0.38	0.69
	ADW (mesio-distal)	4.3±0.7	0.57±0.77	<0.0001
	MDW (mesio-distal)	7.01±0.87	1.38±0.36	<0.0001
	CDW (mesio-distal)	8.53±0.9	6.1±1.62	0.001
6 months	DH (apical - coronal)	11.09±1.18	8.94±0.94	<0.0001
	ADD (bucco - lingual)	11.6±1.91	9.85±0.82	0.016
	MDD (bucco - lingual)	10.77±2.23	7.72±1.32	0.002
	CDD (bucco - lingual)	6.04±0.82	6.75±1.2	0.141
	ADW (mesio - distal)	0.63±0.62	0.77±1.22	0.75
	MDW (mesio - distal)	1.45±0.55	1.61±1.3	0.725
	CDW (mesio - distal)	3.62±1.12	3.9±1.94	0.697
1 year	DH (apical - coronal)	11.09±1.18	8.94±0.94	<0.0001
	ADD (bucco - lingual)	11.6±1.91	9.43±0.89	0.004
	MDD (bucco - lingual)	10.07±2.4	7.2±1.35	0.004
	CDD (bucco - lingual)	5.98±0.8	6.48±1.03	0.243
	ADW (mesio-distal)	0.41±0.5	1.08±1.34	0.155
	MDW (mesio - distal)	1.34±0.48	1.98±2.07	0.354
	CDW (mesio - distal)	3.48±2.16	3.3±2.66	0.87

*Obtained using t-test for independent samples; Bold P values indicate statistical significance; Significant difference (P<0.05). P – Probability value; SD – Standard deviation; DH – Defect height; DD – Defect depth; ADD – Apical DD; MDD – Middle DD; CDD – Cervical DD; DW – Defect width; ADW – Apical DW; MDW – Middle DW; CDW – Cervical DW

Table 2.

Comparison of parameters across time points in each group

Parameter	Time	Group I		Group II
		Mean±SD (mm)	P*	Mean±SD (mm)	P*
DH (apical - coronal)	Baseline	6.79±0.56	<0.0001	7.55±0.83	0.001
	6 months	11.09±1.18		8.94±0.94
	1 year	11.09±1.18		8.94±0.94
ADD (bucco - lingual)	Baseline	7.53±0.68	<0.0001	5.56±0.85	<0.0001
	6 months	11.6±1.91		9.85±0.82
	1 year	11.6±1.91		9.43±0.89
MDD zone (bucco - lingual)	Baseline	4.17±0.75	<0.0001	4.53±0.76	<0.0001
	6 months	10.77±2.23		7.72±1.32
	1 year	10.07±2.4		7.2±1.35
CDD (bucco - lingual)	Baseline	3.25±0.68	<0.0001	3.15±0.38	<0.0001
	6 months	6.04±0.82		6.75±1.2
	1 year	5.98±0.8		6.48±1.03
ADW (mesio-distal)	Baseline	4.3±0.7	<0.0001	0.57±0.77	0.253
	6 months	0.63±0.62		0.77±1.22
	1 year	0.41±0.5		1.08±1.34
MDW (mesio-distal)	Baseline	7.01±0.87	<0.0001	1.38±0.36	0.365
	6 months	1.45±0.55		1.61±1.3
	1 year	1.34±0.48		1.98±2.07
CDW (mesio-distal)	Baseline	8.53±0.9	<0.0001	6.1±1.62	0.027
	6 months	3.62±1.12		3.9±1.94
	1 year	3.48±2.16		3.3±2.66

*Obtained using repeated measure analysis of variance; paired comparisons performed after adjusting with Bonferroni correction; Bold P values indicate statistical significance. Significant difference (P<0.05). P – Probability value; SD – Standard deviation; DD – Defect depth; DW – Defect width; DH – Defect height; ADD – Apical DD; MDD – Middle DD; CDD – Cervical DD; ADW – Apical DW; MDW – Middle DW; CDW – Cervical DW

In Group II, the parameters DH, ADD, MDD, and CDD showed statistically significant increase with time (P < 0.0001). The pair wise comparison showed that the mean difference between baseline and 6 months was statistically significant for all the DD parameters. The difference of apico-coronal DH and CDD between 6 months to 1 year was statistically insignificant; however, the difference of ADD and MDD, between 6 months to 1 year, differed significantly than zero. The ADW and MDW showed statistically insignificant difference, while CDW showed significant difference (P = 0.027) across times. The difference of CDW between baseline and 6 months was statistically insignificant, but at 1 year, the difference was significant as compared to baseline and 6 months.

Table 3 shows the comparison of mean bone gain between two groups with respect to each parameter. The mean bone gain was significantly different corresponding to apico-coronal DH (P < 0.0001), MDD (P = 0.002), and ADW (P < 0.0001) DW in the middle zone (P < 0.0001). A greater amount of vertical and horizontal bone gain was evident in Group I as compared to Group II.

Table 3.

Comparison of mean bone gain between two groups

Parameters	Group, mean±SD (mm)		P*
	I	II
DH (apical - coronal)	4.30±1.32	1.39±0.94	<0.0001
ADD (bucco - lingual)	4.07±2.08	3.87±1.30	0.8
MDD (bucco - lingual)	5.90±2.32	2.67±1.48	0.002
CDD (bucco - lingual)	2.73±0.89	3.33±0.98	0.17
ADW (mesio-distal)	−3.89±0.82	0.51±1.23	<0.0001
MDW (mesio-distal)	−5.67±0.93	0.60±1.96	<0.0001
CDW (mesio-distal)	−5.05±2.30	−2.80±3.50	0.107

*Obtained using t-test for independent samples, Bold P values indicate statistical significance; Significant difference (P<0.05). P – Probability value; SD – Standard deviation; DD – Defect depth; DW – Defect width; DH – Defect Height; ADD – Apical DD; MDD – Middle DD; CDD – Cervical DD; ADW – Apical DW; MDW – Middle DW; CDW – Cervical DW

Table 4 shows the comparison of graft resorption between two groups with respect to each parameter. The mean graft resorption was significantly different corresponding to ADD (P < 0.0001) and ADW (P = 0.015). Table 5 provides the number of cases with graft exposure at different time points in two groups. At baseline, none of the cases in either group had exposure. At 6 months, 3 (30%) cases in each group had exposure; and the proportion continued till 6 months. There was no increase in the number of cases with graft exposure.

Table 4.

Comparison of mean graft resorption between two groups

Parameters	Group, mean±SD (mm)		P*
	I	II
DH (apical - coronal)	0±0	0±0	-
ADD (bucco - lingual)	0±0	0.42±0.26	<0.0001
MDD (bucco - lingual)	0.70±0.30	0.52±0.27	0.174
CDD (bucco - lingual)	0.06±0.10	0.27±0.35	0.086
ADW (mesio-distal)	0.22±0.36	−0.31±0.51	0.015
MDW (mesio-distal)	0.11±0.33	−0.37±0.81	0.1
CDW (mesio-distal)	0.14±1.87	0.60±1.63	0.565

*Obtained using t-test for independent samples, Bold P values indicate statistical significance Significant difference (P<0.05), P – Probability value; SD – Standard deviation; DD – Defect depth; DW – Defect width; DH – Defect height; ADD – Apical DD; MDD – Middle DD; CDD – Cervical DD; ADW – Apical DW; MDW – Middle DW; CDW – Cervical DW

Table 5.

Graft exposure at different time points in two groups

Graft exposure at	Status	Group
		Group 1		Group 2
		n	Column n %	n	Column n %
Baseline	No	0	0.0	0	0.0
	Yes	0	0.0	0	0.0
6 months	No	8	80.0	9	90.0
	Yes	2	20.0	1	10.0
1 year	No	8	80.0	9	90.0
	Yes	2	20.0	1	10.0

n – Number of patients

Table 6 shows statistically significant difference of VAS score distribution between two groups. The median score was higher in Group 2 as compared to Group 1. For all VASs, the higher the scores, the greater the satisfaction with the procedure. Table 7 shows the comparison of the PREMs and significant differences were found among both the groups. Table 8 gives the comparison of the PROMs and significant differences were found. The global satisfaction score was significantly better in Group II as compared to Group I.

Table 6.

Descriptive statistics for visual analogue scale score of subjects in two groups

VAS score	Group		P
	I	II
n	10	10	<0.0001*
Mean	33.40	42.70
Median	34.50	42.50
SD	4.48	2.91
Minimum	26.000	38.000
Maximum	39.000	47.000

*Obtained using Mann–Whitney U-test. Bold P values indicate statistical significance; Significant difference (P<0.05); P – Probability value; VAS – Visual analogue scale; n – Number of patients; SD – Standard deviation

Table 7.

Comparison of patient reported experience measures responses between two groups

	Group		P*
	I, n (%)	II, n (%)
Q1
Agree	5 (50.0)	4 (40.0)	0.999
Strongly agree	5 (50.0)	6 (60.0)
Q2
Agree	9 (90.0)	2 (20.0)	0.007
NAND	0	1 (10.0)
Strongly agree	1 (10.0)	7 (70.0)
Q3
Agree	8 (80.0)	6 (60.0)	0.476
Disagree	0	1 (10.0)
Strongly agree	2 (20.0)	3 (30.0)
Q4
Agree	4 (40.0)	1 (10.0)	0.015
Disagree	5 (50.0)	1 (10.0)
NAND	1 (10.0)	3 (30.0)
Strongly agree	0	5 (50.0)
Q5
Agree	7 (70.0)	5 (50.0)	0.675
Disagree	0	1 (10.0)
NAND	1 (10.0)	1 (10.0)
Strongly agree	2 (20.0)	3 (30.0)

*Obtained using Chi-square test with correction for continuity; Bold P values indicate statistically significant difference between the responses of two groups; Significant difference (P<0.05). P – Probability value; n – Number of patients; NAND – Neither agree nor disagree; Q – Question

Table 8.

Comparison of patient-reported outcome measures responses between two groups

	Group		P*
	I, n (%)	II, n (%)
Q11
Normal movement of jaw	0	8 (80.0)	0.001
Restricted jaw movements	6 (60.0)	2 (20.0)
Slightly restricted jaw movements	4 (40.0)	0
Q12
Ability to eat	0	7 (70.0)	0.0002
Disability to eat	0	2 (20.0)
Disability to eat	10 (100.0)	0
limited ability to eat	0	1 (10.0)
Q13
Disturbed sleep	3 (30.0)	0	0.051
Fatigue	3 (30.0)	3 (30.0)
General weakness	2 (20.0)	0
Normal	2 (20.0)	7 (70.0)
Q14
Absolutely not anxious	0	5 (50.0)	0.003
Anxious	7 (70.0)	2 (20.0)
Depressed	3 (30.0)	0
Slightly anxious	0	3 (30.0)
Q15
No social interaction	10 (100.0)	3 (30.0)	0.005
Social interaction	0	7 (70.0)
Q16
Confusion	4 (40.0)	3 (30.0)	0.001
Impaired alertness	6 (60.0)	0
No psychological impairment	0	7 (70.0)
Q17
Feeling of sickness & malaise	4 (40.0)	0	0.093
Overall health normal	6 (60.0)	10 (100.0)
Q18
Satisfied with bodily appearance	2 (20.0)	10 (100.0)	0.001
Unsatisfied with bodily appearance	8 (80.0)	0
Q19
Employment affected	6 (60.0)	0	0.015
Resumed work	4 (40.0)	10 (100.0)
Q20
Extremely satisfied	2 (20.0)	0	0.107
Neither satisfied nor dissatisfied	2 (20.0)	2 (20.0)
Not satisfied with care	0	1 (10.0)
Satisfied with care	3 (30.0)	7 (70.0)
Unsatisfied with care	3 (30.0)	0

*Obtained using Chi-square test with correction for continuity; Bold P values indicate statistically significant difference between the responses of two groups; Significant difference (P<0.05). P – Probability value; n – Number of patients; Q – Question

DISCUSSION

The present study evaluated horizontal and vertical bone gain at 6 and at 12 months after alveolar ridge augmentation with both autogenous bone blocks harvested from the symphysis of the mandible and with allogeneic bone blocks and the overall patient-reported outcomes. The results of the present study revealed that in both the groups the regenerative techniques improved the morphology of the edentulous ridge, thus allowing for a more ideal implant placement, better emergence profiles, and thereby enhancing the overall harmony of the implant-supported prosthesis in relation to the adjacent and opposing dental elements.

The results of the present study indicate that there is significant increase in the apico-coronal DH in both the groups demonstrating successful vertical augmentation of the bony defect. However, the amount of apico-coronal bone gain was significantly greater in Group I as compared to Group II (P < 0.0001). The enhanced osteogenesis by inductive and conductive processes and early revascularization of the autogenous block is possible explanation for the improved maintenance of graft volume.

Resorption of the alveolar ridge is a multifactorial and biomechanical problem resulting from a combination of anatomical, metabolic, and mechanical factors. These factors vary from person to person, and the various contributions from multiple different factors account for the differences in resorption between individuals.[19–22] No vertical graft resorption was observed in either groups. This finding is in contrast with the results by Aslan et al.[23] where they found a mean percentage of vertical graft resorption of 5.4% following the use of a cortical block allograft for augmentation of the alveolar ridge after 5 months of healing. Also Kloss et al.[16] reported the vertical graft shrinkage of about 5.7% ± 5.6% with autogenous while 5.9% ± 6.1% with allogeneic block in ridge augmentation procedures.

In the present study, it was also found that the bucco-lingual ADD and MDD was significantly improved, thereby implying bone fill in the apical and middle area. This actively indicates better revascularization and perfusion in the apical and the middle areas as compared the crestal level in case of both types of grafts. However, the results were more pronounced in the middle zone of the buccolingual aspect of autogenous graft as opposed to allograft (P < 0.002). This is in contrast with previous results.[16]

The graft resorption at the apical level was found to be 4.26% in Group II while no resorption was observed in Group I. This particularly may be attributed to the fact that the mandibular bone blocks are more resistant to resorption owing to the vast amount of cortical bone; however, this advantage may hold a risk in terms of integration of the block and natural bone, due to the limited revascularization and poor regeneration potential of the block many a times leading to graft exposure.

Pereira et al.[24] found that the mean horizontal bone resorption of cortico-cancellous fresh-frozen allogeneic bone blocks between the augmentation procedure and re-entry was approximately 7.1%. Spin-Neto et al.[25] reported an average horizontal graft resorption of 8.3% at 6–8 months after cortico-cancellous fresh-frozen block bone allograft placement. These values are considerably higher than the values we found for the freeze-dried cancellous allogeneic bone blocks (4.26%) and the autogenous bone blocks (0%). The graft resorption in the middle and cervical areas did not differ significantly in both the groups. These results are along the lines of the findings by Kloss et al.[16] The mean cervical and apical bucco-lingual bone gain was not significant when compared in both the groups. Nevertheless, these measurements are near to those found in the previous studies.[16,26,27] Comparable results were found in the mean bone gain in the cervical zone (bucco-lingually) in both the study groups strengthening the credence that allograft can be a suitable substitute to gold standard autogenous bone block. This outcome is in accord with the previous studies.[16,28]

In the present study, we found graft exposures predominantly from the cervical and middle zone of bucco-lingual aspect at the site of the ossteosynthesis screws in about 20% of cases in Group I and 10% of cases in the Group II. This could be the probable cause of the minimal bone gains in the cervical and the mid buccal region as compared to the apical region of the defect area. The particular reason for the circumstance is that the graft exposures are more prevalent with the autogenous symphyseal grafts.[29]

In both the groups, GBR membrane was used to cover the defect site in the sense of guided bone regeneration and to stabilize the augmentation material to prevent micro-movement. The resorbable chorion membrane was chosen because of its space-maintaining properties in these challenging defect morphologies. The chorion membrane becomes very pliable when hydrated and closely adapts to the contours of the underlying surface. Owing to its self-adherent property, it does not easily displace from underneath the over laying flap and does not need to be fixed into place using sutures or tacks.

To the best of our knowledge, this is the first ever study of its kind evaluating PREMS and PROMS in autogenous and allogenic block grafting procedures. These questionnaires provide adjunct outcomes assessment of the quality of care that can add to the evidence-based knowledge and ultimately best practice. PROMS most likely makes us understand the trajectory of events from pretreatment to different time periods posttreatment thereby facilitates our understanding of what and when this is preferable to do.

In the present trial, besides the clinical outcomes the patient-centred outcomes were also assessed in both the groups. The VAS score obtained from Group II was significantly more as compared to Group I illustrating greater satisfaction and comfort with the operative procedure. Similar results were reported by Andersson in 2008.[30] Furthermore, the patients responded favorably to the PROMS questionnaire in favor of allogenic block. Significantly higher number of patients from Group I experienced restricted jaw movements, disability to eat, disturbed sleep and fatigue, more anxiety owing to the thought of two operating site morbidity, etc., Furthermore, all of the Group I patients had no social interaction soon after the procedure for a few days. A significantly greater number of Group I patients suffered from impaired alertness and mental confusion and were unsatisfied with facial appearance which affected their employment. However, majority of study participants were satisfied with the care provided pre, intra and postoperatively by the investigators. This implies that the allogenic block bone grafting is a more acceptable alternative to autogenous block bone with increased patient compliance, acceptability and satisfaction.

Due to the cost of the treatment as well as patient reluctance, there was a limit in the number of patients included in this study. Furthermore the defect volume was not exactly determined, but it was approximated. More confirmatory results can be obtained with larger sample size and long term follow-up periods to evaluate the effectiveness of this method for patients with alveolar ridge defects in need of dental implant placement.

CONCLUSION

Within the limitations of the study, it can be concluded that the apico-coronal bone gain is better achieved with the autogenous bone blocks though with lesser resorption rates as compared to the allogenic counterparts. However, a greater patient satisfaction and acceptance with less discomfort has been observed with allogenic bone blocks. Better PROMS and PREMS are reported when allogenic bone is used for bone augmentation procedures.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.